# 2002 25oohd engine oil question?



## buckhigh (Oct 21, 2008)

Just bought the truck at 44k miles and have put nothing but synthetic in it ever since. I'm on my 3rd oil change. 1st one Mobil truck synthetic, the last 2 Quaker 4x4 synthetic. I usually run Mobil 5w30 or Quaker 5w30 both synthetic depending whats on sale or in stock. I notice when I refill the empty quarts, I'm about a half a quart shy of the full 6 quarts. Am I burning oil? Rings bad? Or is that about normal with Chevys? I change the oil every 3k miles to keep her happy. Thanks for all the insight guys!


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## TEX (Nov 24, 2003)

remember your oil filter holds prob close to a qt of oil. i wouldnt worry about it. i would stick with the mobil 1


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## alivings (Jan 9, 2008)

I have an '02 2500hd with the 8.1 and I run Shell Rotela T synthetic. It burns about a 1/2 - 1 quart every 3000 - 4000 miles. I asked the dealer about it and they told me that because of the piston size some oil will be burnt off over time.


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## naturalgreen (Dec 6, 2008)

pretty standard 
oil filter maybe
half a quart out of 6 is nothing


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## brad96z28 (Aug 21, 2005)

alivings;670811 said:


> I have an '02 2500hd with the 8.1 and I run Shell Rotela T synthetic. It burns about a 1/2 - 1 quart every 3000 - 4000 miles. I asked the dealer about it and they told me that because of the piston size some oil will be burnt off over time.


What weight is that 5 w 40? Lol piston size.


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## alivings (Jan 9, 2008)

brad96z28;670938 said:


> What weight is that 5 w 40? Lol piston size.


Yeah, its 5w40


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## brad96z28 (Aug 21, 2005)

Why 40 weight Did it use alot of oil or have low pressure?


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## alivings (Jan 9, 2008)

Thats the only weight the Rotela T synthetic comes in. The guy that I bought the truck from was running conventional Rotela 15w40 so I kept using the Shell but went synthetic. Pressure is normal.


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## buckhigh (Oct 21, 2008)

Thanks guys for the reassurance. I've been through hell with this truck since I've bought her this past March. She only had 44k miles on her and Chevy has done nothing but take my check book to the bank. I just switched to the Quaker 5w30 4x4 synthetic and probably will switch back to the Mobil 1 synthetic on the next oil change. It feels like she had a more of a kick to her running the Mobil 1.


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## aeronutt (Sep 24, 2008)

It's probably not a bad idea to stick with the Mobil 1 over Quaker. Not sure if the synthetic Quaker is going to be comparable, but a machine shop owner showed me an engine he just got in for a rebuild that was completely packed full of sludge that you could scoop out like axle grease. The engine had only 30K on it and always ran Quaker 10W-30. He said it was because Quaker is parafin based. Ever since then I've never bought anything that says Quaker on it! I use and highly recommend Amsoil products. I'm not a dealer, just a really happy customer. I even use Amsoil lubricants in my lawn mowers and chainsaws. Since switching, I haven't experienced a single failure related to wear of lubricated parts. I wore out a lot of parts before switching.


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## RichG53 (Sep 16, 2008)

If you change the oil when It is hot (warm).. It should all run out ...Preventing any build up ....I have used Quaker for ever never had any problems...I change mine every 2,000 mi's.....Oil & Filter...


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## brad96z28 (Aug 21, 2005)

alivings;671302 said:


> Thats the only weight the Rotela T synthetic comes in. The guy that I bought the truck from was running conventional Rotela 15w40 so I kept using the Shell but went synthetic. Pressure is normal.


You guys are nuts running 15w 40 and 5w 40 In a gas engine.
That motor will be junk! An 8.1 calls for 5 w 30.


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## brad96z28 (Aug 21, 2005)

alivings;670811 said:


> I have an '02 2500hd with the 8.1 and I run Shell Rotela T synthetic. It burns about a 1/2 - 1 quart every 3000 - 4000 miles. I asked the dealer about it and they told me that because of the piston size some oil will be burnt off over time.


No wonder it uses oil !!!!!!!!!!!!


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## alivings (Jan 9, 2008)

How will it be junk?


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## brad96z28 (Aug 21, 2005)

Its way to thick! Do u know what 15w 40 looks like at 0 deg? Viscositly of mud. 5w 40 is better but still no need unless u have really high miles or major oil consumption. The 15W 40 that someone had used is more then likely why it uses oil now.


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## brad96z28 (Aug 21, 2005)

Its one thing if u have a tired worn out engine and ur trying to mask oil consumption with thicker oil.But fuel economy and the engine tolerances where designed for 5w30.


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## alivings (Jan 9, 2008)

brad96z28;671997 said:


> Its way to thick! Do u know what 15w 40 looks like at 0 deg? Viscositly of mud. 5w 40 is better but still no need unless u have really high miles or major oil consumption. The 15W 40 that someone had used is more then likely why it uses oil now.


I bought the truck with 40,000 miles on it and now its about to turn over 80,000. I changed it to the 5w 40 the first oil change I did. It used more oil at first then it does now, but according to the dealer the use is normal. I'm due for an oil change so I'm gonna try the M1 5w 30 and see how it does. Thanks for the input on this, I'd think the dealer would have said something about this oil being to heavy but they didn't.


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## brad96z28 (Aug 21, 2005)

alivings;672035 said:


> I bought the truck with 40,000 miles on it and now its about to turn over 80,000. I changed it to the 5w 40 the first oil change I did. It used more oil at first then it does now, but according to the dealer the use is normal. I'm due for an oil change so I'm gonna try the M1 5w 30 and see how it does. Thanks for the input on this, I'd think the dealer would have said something about this oil being to heavy but they didn't.


 See how it goes It may use more oil though. let us know. Sometimes syitching to synthetic can cause oil consumption. Dont tell the dealer it had 15w 40 in it. They will probally thow away warranty papers.


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## B&B (Nov 4, 2006)

Brad how many 8.1's have you personally owned or oversaw the maintenance on in a fleet environment?


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## bridge577 (Sep 30, 2005)

I called the dealer with same queston, I have two that I bought brand new from factory one with 6.0 other with 8.1 since the day I bought them they have always eatin 1/2 to 1 quart between changes. The dealer claims that's the design and the were made that way on purose. It didn't didn't really satisfy my nerves but everyone I've taked to says same thing, both mine know have ove 150,000 miles on them and run great.


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## buckhigh (Oct 21, 2008)

bridge577;673153 said:


> I called the dealer with same queston, I have two that I bought brand new from factory one with 6.0 other with 8.1 since the day I bought them they have always eatin 1/2 to 1 quart between changes. The dealer claims that's the design and the were made that way on purose. It didn't didn't really satisfy my nerves but everyone I've taked to says same thing, both mine know have ove 150,000 miles on them and run great.


Why would GM design an engine on purpose to eat oil? I can understand at 250k miles you'll see some oil consumption, but why at 50k miles let alone brand new? I don't see how a brand new engine that burns oil is beneficial? Feel free to chime in on this one B&B as I see you really know your engines. Thanks!


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## brad96z28 (Aug 21, 2005)

B&B;673148 said:


> Brad how many 8.1's have you personally owned or oversaw the maintenance on in a fleet environment?


My uncle had an 8.1. With regular oil changes of 5w30 his did not seem to use any oil to speak of between oil changes. I dont see a ton of them compared to the 6.0,Just a few here and there there not popular around here anyway.


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## brad96z28 (Aug 21, 2005)

alivings;670811 said:


> I have an '02 2500hd with the 8.1 and I run Shell Rotela T synthetic. It burns about a 1/2 - 1 quart every 3000 - 4000 miles. I asked the dealer about it and they told me that because of the piston size some oil will be burnt off over time.


I did find out a ton of real good info about oil consumption with the 8.1. Alivings if u want to pm me. I cant send u some good info On some things to try.Im not gona post it on here to have people question it, but most of the info is str8 from gm.:salute:


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## B&B (Nov 4, 2006)

brad96z28;674206 said:


> I did find out a ton of real good info about oil consumption with the 8.1. Alivings if u want to pm me. I cant send u some good info On some things to try.Im not gona post it on here to have people question it, but most of the info is str8 from gm.:salute:


Funny, didn't realize the 8.1's were such a big secret. 

The reason I asked Brad was because your reference to "late model gas engines". While technically yes the 8.1 is a gas engine and yes its a late model they don't adhere to the same design as the others; like the 4.8, 5.3, 6.0 LS family stuff for example and don't have the close tolerances that those engines do. Basically the 8.1's are still like the big block GM's of yearsteryear, namely their not nearly as precision tight on their machined clearances, and do not use a gearator style oil pump like the LS engines do....and its normal for them to use oil.

And the two main reasons they do are the fact that GM spec-ed them for 5W-30 along with the fact that they also use a LOW TENSION OIL RING PACKAGE. And the reasons for both of those details is due to GM trying like gangbusters in an attempt to increase the MPG's on these engines in any way they could when they were released in 2000. Low tension oil rings reduce reciprocating drag, the thinner oil also reduces drag. Those two attributes combined were to increase MPG's...but at a sacrifice of oil consumption.

In real world conditions oil viscosity isn't as critical in the 8.1's as it is in the LS based engines as far as engine longevity is concerned. Those LS engines truly are a tight clearances engine and running too high an oil viscosity can cause them issues, but it doesn't apply to the 8.1's....5W-30 is not thick enough in most situations and will in most cases cause excessive oil consumption.

Under most conditions, and when running dino oil...10W-40 is the best all around viscosity summer AND WINTER viscosity if the truck is worked hard during the winter months. Now in extreme cold conditions such as where the truck is often cold soaked in temps well below 0* then the 5W-30 is better...but thats the ONLY conditions where it's best.

If your using synthetic then use either 5W-50 under ALL conditions, or 15W-40 in conditions where the ambient temp will stay above 0*. After running these 8.1's for years and keeping a very close eye on oil consumption, along with detailed oil analysis on a regular basis this is the "real world" cold hard solution to the best protection with the least amount of oil consumption.


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## brad96z28 (Aug 21, 2005)

B&B;674391 said:


> Funny, didn't realize the 8.1's were such a big secret.
> 
> The reason I asked Brad was because your reference to "late model gas engines". While technically yes the 8.1 is a gas engine and yes its a late model they don't adhere to the same design as the others; like the 4.8, 5.3, 6.0 LS family stuff for example and don't have the close tolerances that those engines do. Basically the 8.1's are still like the big block GM's of yearsteryear, namely their not nearly as precision tight on their machined clearances, and do not use a gearator style oil pump like the LS engines do....and its normal for them to use oil.
> 
> ...


Funny thats not what gm or gm tech say. I have read over 18 posts most form gm tech saying to never ever use 15w40 in an 8.1 it was designed for 5w30 If u could show me some where where gm would recomend using anything but I would love to see that. The only tsb that gm has ever put out concerning a 2002 and changing what oil they recomend is for the 6.6 tsb00-06-0125a It states not to use 15w40 in cold weather below 0 That u should use 5w40. Out of the 1254 currnet tsbs for a 2002 gm truck that is the only one that pertains to what oil grade they goofed up on. And from what I have read, there are many people that use the propper recomended oil weight of 5w30 year round and have no oil consumption issues! And if they do it has absolutely nothing to do with piston rings! There are many other tsb for the 8.1 the pertains to oil consumption. If u are a member of iatn I can send a link to what I am talking about but I am not allowed to re distribute any of the info posted on there.Until gm comes out with a tsb saying that they made a mistake on what grade oil to use I will always continue to go by what the factory recomends to use as im sure they know more then u and me combined.Im trying to help the guy fix his oil comsumption problem the correct way.If u work on these on a regular basis why did u not care to comment on the real world common problems for oil consumption? Oil grade is not the problem atleast according to factorm gm techs.


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## brad96z28 (Aug 21, 2005)

I did pm some things for Alivings to try that gm recomends for oil comsumption. We will see how he makes out.


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## B&B (Nov 4, 2006)

I know all about GM's cheat sheets as I have unlimited access to them myself, and sure your can follow them to the "T" as thats your prerogative to do so, so no impressions there as I'm not basing my comments on cheat sheets that I simply read anyway, I'm biasing them on 8 years of personal experience with a fleet of 34 8.1 equipped trucks that are used throughout different parts of the country that we've been doing maintenance and regular oil analysis on since their very first oil changes when new. In fact it was Blackstone laboratories (who was doing our analysis's) that first recommend to increase the viscosity on them after only the first 6 oil analysis they originally did on these 8.1's after finding unreasonable amount of aluminum present in the samples across the board. They made it quite clear that this unreasonable amount of aluminum stemmed directly from excessive piston scuffing under normal temp running conditions due to thermal shear/breakdown from THE LACK OF OIL VISCOSITY...and yes, at that time we we're running the GM RECOMMENDED 5W-30. Shortly thereafter we switched 4 of them to 5W-50 synthetic and again closely monitored the wear through oil analysis as well as oil consumption between changes for the next 25,000 mi. At the next service interval the lab interestingly found that their recommendation was spot on. Aluminum content had dropped below 5 PPM (parts per million) in every engine, which is much less than the previous 14 PPM that those 4 previously tested at. Oil consumption had also lessened to 1 qt or less per 4000 mi across the board...which the drivers were graciously happy to see as well. And these findings continue to hold true throughout the life span of the engines.

We also used the Rotella 15W-40 in 7 of the new at that time 2003 model year trucks after running them their first 36,000 mi on GM's recommended 5W-30. Although one of them didn't make it to 36,000 mi before it had a short block replaced under warranty due to as GM put it in the repair order "severe position scuffing/bore wear due to _inadequate_ oil viscosity". They claimed that the engine hadn't received the correct oil maintenance or viscosity. But after showing them the very detailed service records that clearly indicated that it was in fact used with the oil viscosity that THEY RECOMMENDED and included the oil analysis that were done on the engine at regular intervals since it was new. They then immediately changed their tune and quietly replaced the short block under warranty with no questions asked. Oh and the GM rep also recommended running 10W-40 instead of 5W-30. But of course we already knew what the answer was there. 

Four of those 2003 trucks now have OVER 220,00 mile's on them. And of those four, the oil analysis are still falling well below the max limit on wear particulates in the oil, and still use 1 qt or less per 4000 mi.

The 2001-2002 trucks running the 5W-50 synthetic that are still currently in the fleet are scheduled to be replaced in the spring. None of which have ever had an internal engine issue.

Bottom line, before you make a comment that someone is going to turn their 8.1 "into junk" by running something other than your beloved Generals recommendations, try to get yourself some hands on real word experience with them first rather than depending on cheat sheets. Because as we all well know, GM's been wrong before.


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## brad96z28 (Aug 21, 2005)

How do u explain all the people that run 5 w30 and have no oil consumption problems at all?


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## brad96z28 (Aug 21, 2005)

And when someone goes back to the dealer with engine problems and u tell them U have been using 15w40 and they take ur warranty papers tear them up and laugh in ur face u can give them that speach and see how far u get.


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## brad96z28 (Aug 21, 2005)

And since when is publicly released tsb's from gm cheat sheets?


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## Sydenstricker Landscaping (Dec 17, 2006)

Good posts B&B!!!! Although I do not own the 8.1, that seems to be true. I remember the 454's and their oil issue that some were having. Throw in 10w40 or thicker, problem went away. Here for instance my Saturn. It is a 1995 1.9L 4 banger with 150K on the clock. I was running what mr general said, 5w30 in it. That SOB burned oil like no tomorrow. Lifters always clacked, etc. This last oil change, 10w30 dino juice, no more consumption. At this interval in the oil life, I would have added a quart by now. The oil hasnt even discolored. I think alot of it boils down to environment factors. Some trucks run great on what is recommended, others you gotta do a little experiment and find out for yourself.


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## B&B (Nov 4, 2006)

Calm down there big boy. First of all I never said changing oil viscosity would fix all the issues common to the automotive world as you seem to want to believe that I'm attempting to do. Some engines use oil, some don't, and as Tom mentioned it can depend on the environment that their run in. But regardless some that are well known to use oil can be lessened with different oils regardless of the family or brand of engine...and the 8.1 is one of them.

The common misconception about automatically voiding a warranty simply because your running an unapproved VISCOSITY would be on a case by case basis just as any possibility such as that. But be sure to recall that if someone is to deny a warranty claim due to the incorrect viscosity of oil, they first have to identify and then PROVE that it was the direct cause of the failure...which is tough to do on a failed engine. Few will even take the bother to do an oil analysis regardless.


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## brad96z28 (Aug 21, 2005)

U really think someone should be running 15w40 in one of these in 0 deg like I stated many many posts ago.Please no round about answer.


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## brad96z28 (Aug 21, 2005)

And u have not heard of using heavier weight oil In the 8.1 causing the oil rings to stick either?


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## B&B (Nov 4, 2006)

brad96z28;675442 said:


> U really think someone should be running 15w40 in one of these in 0 deg like I stated many many posts ago.Please no round about answer.


There's plenty of 8.1 owners out there Brad that are running 15W-40 with excellent results so don't simply base it only on my own personal findings.

Never had any oil ring sticking issues on any GM big block engine that were related to oil viscosity. Ring contamination problems are normally due to coking from lack of maintenance, lack of proper running temps, or excessive rod side clearance...or a combination of, rather than simply oil viscosity.


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## brad96z28 (Aug 21, 2005)

I most definitly wont, I just wanted ur opinion.


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## brad96z28 (Aug 21, 2005)

here is what Workhorse has to say.

Note: SAE 10W-40 has been removed from all
Workhorse recommendations. Research Laboratories
have found generally a 1.2% fuel economy penalty
compared to 10W-30. Of the oils surveyed some
contained inadequate additives and some did not
meet the 10W-40 viscosity requirements. Testing
showed 10W-40 oils tended to be more prone to high
mileage ring sticking. These problems appeared more
frequently in 10W-40 oils. Workhorse also does not
recommend SAE 20W-50 viscosity oils. 
This is from 8.1s in rv's. Maybe relavent maybe not.


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## B&B (Nov 4, 2006)

And I won't take your own personal comment that "You guys are nuts running 15w 40 and 5w 40 in a gas engine" will reduce an 8.1 to junk status either...so we're all good. :salute:


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## brad96z28 (Aug 21, 2005)

Nope did not say that u may want to read a bit closer. see post 15.


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## B&B (Nov 4, 2006)

brad96z28;675528 said:


> Nope did not say that u may want to read a bit closer. see post 15.


All fixed.


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## buckhigh (Oct 21, 2008)

B&B;675565 said:


> All fixed.


Question for you B&B...the first oil change I performed since I recently bought her was 6qts of Mobil 1 5W30 synthetic. When I drained her, she emptied into 5.5 quarts using a K&N oil filter. The half missing quart I'm assuming is still in the oil filter, plus the misc that spilled during drainage. Don't ask me why, but for some reason I switched to Quaker 5W30 synthetic oil and she emptied 5 even quarts. Now I did drop a towel in the oil drainage pan as I was cleaning the underneath. Not sure if what the towel soaked up is my missing oil? So my question to you is; do you think she's burning? Should I switch back to the Mobil 1? What are your thoughts on the Valvoline 5W30 synthetic? Thanks for all your responses guys/gals...great info in this thread!


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## B&B (Nov 4, 2006)

Based on your less than accurate calculations that would be a tough call to say 100% without a shadow of a doubt...especially with the towel involved  but I'd say your fine.

Your first calculation of 5.5 qts was likely more accurate...most filters will hold a pint or so right after removal so I wouldn't be at all concerned with a missing 1/2 qt at the first change. And if you would have kept your calculations more accurate at the second change I'd have to say you would have discovered you had the same quantity as the first, and a pint of consumption between changes on the 8.1's is nothing to be concerned with...it's well within normal spec that's for sure. 

But if it still concerns you, a little more accuracy during your next few changes to keep better tabs on any possible consumption will tell you for sure. But also be aware that how you use the truck can and will effect oil consumption or lack of. The harder you run it the more it may use...  

Of the three brands you mentioned and if your sticking with 5W-30 then use the Mobile 1 as it has the highest burn off rating spec of those three brands in that grade, which can definitely be helpful specific to these 8.1's.


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## 70monte (Feb 5, 2008)

I used to run 5W-30 Mobil 1 in my 98 K1500. I ran it from about 1,500 miles until about 35,000 miles. The 5.7L vortec in this truck didn't seem to like this oil as my wear metals(according to Blackstone Labs) were not that great and my oil consumption was about 1 qrt every 3,000 miles. I switched to 5W-30 Havoline and my wear metals improved and oil consumption was reduced. I tried 10W-30 Mobil 1 a few times in this truck but it seemed to run better on the 5W-30.

B&B,
Is the use of 5W-30 oils mainly for an increase in MPG? What viscosity would you recommend for a 5.7 & 7.4 Vortec with both having around 100,000 miles on them? Thanks.

Wayne


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## B&B (Nov 4, 2006)

Yes it's a well known fact that the lower the viscosity the oil, the less reciprocating drag you'll have which slightly affects the EPA MPG averages for the manufacturer's across the board (in their favor  ), which of course is what they're after.


As for viscosity's on your higher mileage 5.7 and 7.4, generally as the older engines age you want to increase the viscosity. Since I'm sure your aware clearances have a tendency to open up as the engines accumulate miles.

The 5.7's with 100,000 mi or more on them work well with 10W-30 (dino) all year round. But with full synthetic,10W-40 works best. Cuts down on consumption while providing more than enough cold weather protection since it's a synthetic based oil.

The 7.4 is a little different. 10W-40 on dino oil, and either 10W-40, 5W-40 (<--can be tough to find), or 15W-40 synthetic works best in the high mileage big blocks as per careful oil analysis and oil consumption monitoring. As you increase the viscosity, the big blocks graciously reward you with less oil consumption and if you do an oil analysis you'll also find higher TBN's since you'll have less oil dilution from the bigger bore sizes that you have on the 7.4's (applies to the 8.1's too).


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## 70monte (Feb 5, 2008)

B&B,
Thanks for the info. I will try your suggestions. The 7.4L is due for an oil change soon. When I first got it about a year ago, I think it had a thicker oil in it because when I did change it, I used 5W-30 Havoline and I had some tapping from the engine until it started warming up which I didn't have before. I run 10W-40 in the 396 BB in my 70 Monte Carlo. I tried 10W-30 in it initially but it didn't like it.

I have not done an oil analysis on the 7.4L yet. I need to do a few to see how its wearing. I haven't done one on the 5.7L in about three years but I haven't drove it much either. I did oil analysis on the 5.7L for about three years and it was pretty interesting to see the results. It told me when my intake manifold gasket began to leak the last two times even though you couldn't tell by looking at the oil. It also showed me I wasn't getting my money's worth with the Mobil 1.

Just out of curiousity, if I was ever to rebuild or install a new engine in either of these trucks, do you recommend starting out with the recommended 5W-30 or stepping up to something higher?. Thanks again for all of your help.

Wayne


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## B&B (Nov 4, 2006)

Oil analysis's are quite beneficial aren't they Wayne? They'll tell you much more about the correct oil for your application than any owners manual or oil advertisement ever will. Adds a few dollars to the maintenance on a vehicle but will give you way more back in info into the health of the engine, as well as info on the best oil to run in the application. Money well spent as far as I'm concerned. Factory recommendations are just that, a recommendation. Doesn't in any way mean "the best" for the application. 

I'm not a bit surprised that the 5W-30 didn't work so well in your vintage big block. The old school engines were never designed to run modern low viscosity oils. In fact if you do a little research on what was recommended back then for you 396 (for example) you'll discover that straight 30 wt was one of the viscosity choices back then..totally different than today's oils. So the 10W-40 is a good choice. In fact 15W-40, 15W-50 are also good choices on the old big blocks since they're very loose on their intended running clearances by design. 


As for a fresh 5.7 or 7.4, start the 5.7 on 10W-30 dino oil until its accumulated some miles....approx 5-10,000 or so. And then go back to the 10W-30 synthetic from there until it again gets near the 100,000 mile mark, and then switch to one of the viscosity's I detailed before if deemed beneficial via analysis.

The 7.4's I never run 5W-30 dino oil in them no matter it's age or mileage. Oil analysis' have clearly shown me that 5W-30 in most engines that have a bore size larger than about 4 1/8" isn't ideal as far as wear, oil consumption, or final TBN's at analysis time. Start with 10W-30 (again dino) for its first 5-10,000 miles and then switch to either the 10W-40 or 15W-40 synthetic from there. 

This is all for 0* or above ambient temps.


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## 70monte (Feb 5, 2008)

Yes, oil analysis is interesting. It also can help you discover a potential engine problem. Have you ever been to the bobistheoilguy.com website? There is a section where people post their oil analysis results. Its a pretty good oil based website.

My 396 has only about 15,000 miles on the rebuild. I never did try to use 5w-30 in it as I figured it would be too light.

Thanks for all of the info. I appreciate it.

Wayne


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## RichG53 (Sep 16, 2008)

GEEE B B You got me all confused again ... I have an 01 2500 HD with about 120,000 + mi's. I bought it used With about 115,000 ... I have been using 10w30 which in an earlier post you said It would be fine...I did notice some oil loss..I have switched to 5w30 for winter it clacks about the same on start up ...But so far a couple hundred mi's. on the 5w30 oil change and don't see any oil use (yet).... So I ask can you please set the RECORD straight ....??? What is best... Thank you.. !!!!!


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## B&B (Nov 4, 2006)

RichG53;679009 said:


> GEEE B B You got me all confused again ... I have an 01 2500 HD with about 120,000 + mi's. I bought it used With about 115,000 ... I have been using 10w30 which in an earlier post you said It would be fine...I did notice some oil loss..I have switched to 5w30 for winter it clacks about the same on start up ...But so far a couple hundred mi's. on the 5w30 oil change and don't see any oil use (yet).... So I ask can you please set the RECORD straight ....??? What is best... Thank you.. !!!!!


Your truck is 6.0 equipped right Rich? If so then either viscosity should be fine with the mileage that you have on it. Never saw much of a differences between 5W-30 and 10W-30 on the 6.0's as far as through oil analysis anyway. But the differences between synthetic and dino based oil does make a difference.


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## B&B (Nov 4, 2006)

70monte;678622 said:


> Yes, oil analysis is interesting. It also can help you discover a potential engine problem. Have you ever been to the bobistheoilguy.com website? There is a section where people post their oil analysis results. Its a pretty good oil based website.
> 
> Wayne


 Forgot about that site since I had run across it once a long time ago, some good stuff on there. His gear oil tests are interesting indeed. :salute:


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## buckhigh (Oct 21, 2008)

B&B;676813 said:


> Based on your less than accurate calculations that would be a tough call to say 100% without a shadow of a doubt...especially with the towel involved  but I'd say your fine.
> 
> Your first calculation of 5.5 qts was likely more accurate...most filters will hold a pint or so right after removal so I wouldn't be at all concerned with a missing 1/2 qt at the first change. And if you would have kept your calculations more accurate at the second change I'd have to say you would have discovered you had the same quantity as the first, and a pint of consumption between changes on the 8.1's is nothing to be concerned with...it's well within normal spec that's for sure.
> 
> ...


Thanks B&B...she's actually the 6.0 Vortec, not the 8.1. Is the burn ratio the same b/w the 2 engines and would you still recommend the Mobil 1 for the 6.0?


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## RichG53 (Sep 16, 2008)

*Dino---Synthetic*



B&B;679779 said:


> Your truck is 6.0 equipped right Rich? If so then either viscosity should be fine with the mileage that you have on it. Never saw much of a differences between 5W-30 and 10W-30 on the 6.0's as far as through oil analysis anyway. But the differences between synthetic and dino based oil does make a difference.


B B Could you please explain what the difference is or the better of the the two and why ???? By dino I believe you mean regular oil correct... !!!!! Thanks ! !


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## B&B (Nov 4, 2006)

RichG53;680138 said:


> Could you please explain what the difference is or the better of the the two and why ???? By dino I believe you mean regular oil correct? Thanks ! !


Synthetic has shown time and time again to reduce or eliminate issues that are common to the regular old "dino" (conventional) oil. Like for example reduced wear, higher TBN's at oil change time (which indicates better protection capability over the life of the oil), improved cold flow and starting, as well as a small improvement in MPG. The slight extra MPG won't normally offset the extra cost of the synthetic but it will reward you with better engine protection and less wear.


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## B&B (Nov 4, 2006)

neols;680109 said:


> Is the burn ratio the same b/w the 2 engines and would you still recommend the Mobil 1 for the 6.0?


 I feel the Mobil 1 is the better of those two specific choices yes. I've had QS come back with some strange results that were cleared up simply by changing brand in the same engine. One reason why I'm not a big QS fan. 

Usage rates are very different between the 6.0 and the 8.1. The 6.0's are generally a very low oil consuming engine. Many out there won't use a drop between changes. The 8.1's on the other hand are well known for liking their oil, and oil type and viscosity are some of the ways to slow it down or eliminate it altogether. Not usually an issue on the 6.0's.


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## RichG53 (Sep 16, 2008)

B B--TBN's ?????


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## RichG53 (Sep 16, 2008)

What weight of synthetic oil to run in a 6.0 ???? with 120,000 mi's.....


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## B&B (Nov 4, 2006)

TBM = Total Base Number

The TBN of oil is the measure of an oils alkaline reserve, or in other words the ability of the oil to neutralize acids from the normal combustion process. Severe depletion of the TBN results in acidic corrosion within the engine, which of course you definitely don't want.

Maintaining a correct alkaline reserve is critical in preventing unnecessary corrosion of the upper piston, piston rings (helps to prevent sticking  ) and bearings. Additionally, low TBN numbers are indicative of reduced oil detergency which at the end of the oils life means that it wasn't the right oil for the job at hand. The higher the oil's TBN, the more effective it is in suspending wear-causing contaminants as well as reducing the corrosive effects of acids created from combustion over an extended period of time...namely until the next oil change.

120K on a 6.0 I'd start with 10W-30 synthetic Rich, and after the second oil analysis go from there (if deemed necessary). But 10W-30 synthetic has always shown good results from all of my findings so it's likely it's also the best oil for your application. :salute:


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## buckhigh (Oct 21, 2008)

B&B;681011 said:


> I feel the Mobil 1 is the better of those two specific choices yes. I've had QS come back with some strange results that were cleared up simply by changing brand in the same engine. One reason why I'm not a big QS fan.
> 
> Usage rates are very different between the 6.0 and the 8.1. The 6.0's are generally a very low oil consuming engine. Many out there won't use a drop between changes. The 8.1's on the other hand are well known for liking their oil, and oil type and viscosity are some of the ways to slow it down or eliminate it altogether. Not usually an issue on the 6.0's.


Thanks for your time and education on this. Sorry for seeming anal about this truck, but she's been nothing but a money pit since I've bought her. Now that I know the 6.0 shouldn't eat a drop of oil, I will definitely monitor the usage from here on out. I checked the dipstick the other day and its is right on the max fill line, so knock-on-wood it will stay there. What do you recommend to help monitor usage? Filling up the empty quarts or weekly checking of the dipstick? Or are both practical? I bought her at 44k miles, so i'm praying the 6.0 is still solid even with all the other problems I've had to deal with. I've checked over and over for signs of oil leaks around the engine and don't see a drop anywhere. The exhaust fumes even look/smell normal. So maybe its just me second guessing myself on this...


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## RichG53 (Sep 16, 2008)

B B Thanks A Lot your knowledge is priceless....!!!!!!!


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## B&B (Nov 4, 2006)

You'll find using reusing the oil containers is about the most accurate way to check for consumption as long as you allow plenty of time for the filter to expel it's contents...at least over night at the minimum but you still won't get 100%. So be sure to take that little bit of loss into your calculations. You'll also want to monitor it over a few oil changes, not simply on a single one if you want the most accuracy.

But bottom line, if your running 3 or 4 thousand miles between changes and you discover it uses a 1/2 qt or less...consider it just fine as a 1/2 qt is nothing to be concerned with.


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## Rhyno6 (Dec 20, 2008)

The other day I stopped in at GM dealer and there serice department showed me the spec tollerance sheet for my 8.1 because I was worried about it using Oil. Get this anyone that don't believe me can call there dealer and they'll so you. The 8.1 can use 1 quart per 100 gallons of gas before they will even consider it for warranty. I KID YOU NOT... I can give you the dealers number for any doubters


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## Doom & Gloom (Mar 2, 2008)

aeronutt;671441 said:


> It's probably not a bad idea to stick with the Mobil 1 over Quaker. Not sure if the synthetic Quaker is going to be comparable, but a machine shop owner showed me an engine he just got in for a rebuild that was completely packed full of sludge that you could scoop out like axle grease. The engine had only 30K on it and always ran Quaker 10W-30. He said it was because Quaker is parafin based. Ever since then I've never bought anything that says Quaker on it! I use and highly recommend Amsoil products. I'm not a dealer, just a really happy customer. I even use Amsoil lubricants in my lawn mowers and chainsaws. Since switching, I haven't experienced a single failure related to wear of lubricated parts. I wore out a lot of parts before switching.


That motor might have had 30K on it but with only 1 oil change, the day it was built! LOL If you change your oil every 3000-4000 it doesnt matter what you use, it wont sludge up like that. None of my vehicles ever have.


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## RCsLawncare (Oct 24, 2008)

my 8.1 uses oil, but was told it was normal. It does have low oil pressure though and did not know until I changed the oil. It still runs fine, just have to be on top of checking and I always run Lucus oil stabilizer.


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