# Blowing smoke on startup only?



## kbsnow (Oct 22, 2009)

OK, heres the issue. I just changed intake manifold gaskets on my 91 5.7 tbi and no leaks, BUT, I am now blowing a puff of smoke on startup after it sits for a while. Now, I always used Mobil Clean 5000 and NEVER blew smoke. After the gasket job, I bought 5 qts of Oreilly's 5-30 for $1.99 each to run through and clean any gunk from the engine. 

Could it be the cheap oil? Do you think this will go away if I switch back to my regular oil? The truck has 172,000 miles and runs like a clock.


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## 2COR517 (Oct 23, 2008)

Sounds like valve seals


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## streetsurfin' (Jan 22, 2004)

Are you sure you didn't drop any old gasket material or other debris that may have plugged an oil drain gally at the back of the heads? Old valve seals on high mileage engines can degrade and chunk apart, leaving pieces partially plugging the drains. Oil builds up on top of the head. Whether drains are restricted or not it could still be bad seals.


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## theplowmeister (Nov 14, 2006)

2COR517;1040763 said:


> Sounds like valve seals


Ditto

OK message to short to post


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## kbsnow (Oct 22, 2009)

Yea I figured its probably the valve seals. I kept everything clean, and used my shop vac to catch any gasket material when I was scraping. I plugged all the head openings real well, and never had the valve covers off...didn't need to. $10 for Felpro seal kit, plus whatever valve cover gaskets cost. Oh well, got all summer to do it.


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## theplowmeister (Nov 14, 2006)

What color is the smoke?


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## 2COR517 (Oct 23, 2008)

theplowmeister;1040841 said:


> What color is the smoke?


Oooooh. Good question


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## kbsnow (Oct 22, 2009)

Blue..its oil..and you can smell the oil...


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## kbsnow (Oct 22, 2009)

The HECK with changing the seals. I'm just gonna put some high mileage oil in it, 10w-30, and hope for the best. Its a plow truck only, gets very little summer use, and its not worth the hassle.


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## cubicinches (Oct 19, 2008)

kbsnow;1041132 said:


> The HECK with changing the seals. I'm just gonna put some high mileage oil in it, 10w-30, and hope for the best. Its a plow truck only, gets very little summer use, and its not worth the hassle.


You took the words right out of my mouth...


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## MickiRig1 (Dec 5, 2003)

An Engine with that many miles will puff a little smoke on startup. I would not worry about it unless it leaves a trail of smoke behind it all the time. My 89 puff's oil smoke at startup, it still passes Emissions Checks every time.


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## KSikkema (Oct 7, 2008)

Not too much to worry about as they almost all do it. IF you do the repair though, just remember that you must pressurize the cylinder with air in order to prevent the valve from falling into the cylinder when you remove the valve keepers and spring! Not too sure how much experience you have with this, but it is something some people may overlook


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## kbsnow (Oct 22, 2009)

Thanks for all the responses. I'm not even gonna worry about it. It is MUCH better with the Castrol High Mileage 10w-30. I'm thinking its been blowing smoke a while, but was not noticable until I put some CHEAP oil in. Since it is a plow truck, and doesn't smoke while driviing, and is still a solid and a strong runner, I'm gonne leave it be. 

I have rebuilt many an engine, and don't think its worth the hassle to do the seals, etc...


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## MickiRig1 (Dec 5, 2003)

might even think about stepping up to a 40 weight oil. I have had good luck with a heavier weight oil with oil useage.My Daughter's Toyota would go through a QT a week of 30 weight. I went to 40 weight and it's gone 2 weeks without a quart used. My Automotive repair course instructor always told us to go up a grade on oil changes. This cures oil useage he said.


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## kbsnow (Oct 22, 2009)

,,now when you say up a wait to 40w, do you mean 10w-40, or straight weight? For the summer I was thinking of straight weight for the little driving it will do, and go back to the 10w-30 for winter.


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## rsails (May 8, 2008)

*Advice needed - Replacing Vavle seals 84 RC*

All

First time replacing valve seals.

I order intake and exhaust seals
2 - new valve covers

borrowing adapter for compressor and valve compression tool.

Any words of advice before I tackle this project?


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## kbsnow (Oct 22, 2009)

Once the valve covers are off, make sure you put rags in the head to block the oil gallies so IF you drop the old seals they don't fall into the engine. Do you know the sequence for tightening the rockers? That is also a critical but easy step. I can't explain it but their are videos on YouTube that show you exactly how it is done.


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## MickiRig1 (Dec 5, 2003)

Leave the push rods in-place,if you remove them keep them in order to where they go.
Little dabs of grease on the inside of the keepers on the valve shafts help to keep them in-place. Make sure you have the book or know the procedure for torquing down the rocker arms. Clean all the sealing surfaces well and wipe down with solvent/paint thinner/brake cleaner/etc so it will seal well. Before you put the valve covers on. Unplug the coil so it will not start. Wind the engine a few times and make sure all the valve keepers have stayed in-place. Then install the valve covers. Don't forget to plug in the coil.


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