# Is too much oil really worse than too little?



## ksland (Nov 27, 2002)

Ever hear someone tell you that too little oil in your engine is better than too much?

This is my experience with this....
I just fixed my uncles truck because of overfilling the oil. 

One morning he checked his oil preparing for a long trip. It read 2 quarts or so down. The truck is a 94 Chevy 1500 4.3L by the way. Anyhow... he added 2 quarts.

He then took off and drove about 10 or so miles (so he says). The truck started losing power and ended up skipping and misfiring. He pulled over, check the oil again and this time realized that he had overfilled the oil by 2 quarts. For some reason he misread the dipstick. He then limped it home, drained the oil and replaced the spark plugs that were all covered in carbon.

After messing with it himself for a couple days he brought it to me with a serious running problem. After some simple diagnostic procedures I found there was no compression in the #4 cylinder. I then removed the passenger valve cover to find a broken pushrod, and a rocker arm off to the side. At that time I check to see if the valve was opening and closing properly and noticed it was jammed.

What happened? In the short time he drove the truck with too much oil, the carbon from the oil splashing up and sucking in through the pcv valve, piston skirts etc... it had built up a huge amount of carbon in the cylinders. This built up on the exhaust valve, bound it up which slowed itself from closing and the piston hit it bending it slightly.

Long story shorter.... I started at 8am... pulled the head off, replaced the valve, reseated it, and put a new pushrod, head gasket, intake gaskets etc.. and had the truck purring like a kitten by 5pm (pat on the back) this included a sit down lunch, and parts chasing.

Is too much oil worse than too little? YES!!


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## Nascar Fan (Oct 26, 2003)

*Oil consumption*

Did you by any chance check the intake for deposits?The reason I ask is that the 4.3 is not the cleanest engine and if it was over filled with oil it would loosen any build up of deposits quicker because of internal pressure in the cylinder on the compression ring.GM is famous for breaking the oil ring,when it comes into the cylinder--wheather it's volutary or somebody dumps Kerosene down it after an oil change . Mileage and debris in the intake are huge factors cylinder temps----(not ALL oil commercials are decieving) but-- for the 4.3,3.4,3.1,5.0 and Earlier---86 to 96 model 5.7 engines.Really though the Vortec is famous for the injector/pressure regulator assembly to go bad and the build up of crap in the intake is insane from it.Just another thought for you.


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## ksland (Nov 27, 2002)

the intake valves and runners were very clean considering


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## Nascar Fan (Oct 26, 2003)

*Wow*

Just really seems that two quarts over should not cause this.I could see even a lifter letting go but still.....I am not doubting you just curious is all.


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## Mower For Less (Nov 2, 2004)

My understanding of overfilling the oil is that the crank will start agitiating the oil in the pan, causing foaming, and in turn loss of lubrication. I would think, as mentioned above, that it would take alot more than 2 quarts to cause such a build up of pressure that the damage would be caused from that alone. I would think that loss of lubrication would effect all cylinders pretty equally.

Kevin


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## Nascar Fan (Oct 26, 2003)

*All cylinders equally*

Not always,in my thinking almost never as the old saying comes to mind,"only as strong as it's weakest link".2 quarts is not really excessive enough to cause foaming because you still have circulation of oil.Bieng that the right rear cylinder has higher cylinder temps because of lower air circulation,and the EGR it would cause higher temps within the cylinder.I could see a valve that bent under heat/load/or any other variable you want to give,causing this,but two quarts?almost unheard of here.I will write it in my book to remember.I finished a 94 350 chevy 3 weeks ago that melted number 8 exhaust valve----------HEY!!!!just thought of this while typing did you check the E.G.R. valve?????????????--------If that hangs open---Deposits---and very little of it ------will cause this to hang open will cause overheating of that cylinder and valve thereby either causing it to swell open long enough for the piston to hit it and bend it or melt it altogether.BTW you will not always get a check engine light to tell you this either becuse so long as the ecm does not pick up excessive ping or misfire it will not trip the light.Just another thought,because as i i said that was the problem with the 350 I just rebuilt the heads on,and a 4.3 is a 350 with the 2 back cylinders cut off in a nutshell.


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## V10SCOTTY (Feb 2, 2005)

He's lucky thats all that happened.I seen a guy pick up his new ford pick-up and he thought he should put synthetic oil in it.Well he over filled it drove down the road about a km or 3/4 of a mile depending where your from and since the oil was overfull the crankshaft hit the oil causing to run way out of balance well after enough of the crankshaft hitting the oil the crank finally jusy grenanded and took half the block with it.....oops huh.thats why nascar and nhra etc. have special oil pans to keep the oil from hitting the crank.Most guys will put a windage tray in their performance engines to stop the oil from splashing the crank.Oil is supposed to go through the journals and thats it.On a 8hp briggs its a different story the crank is designed to splash oil for lubrication.So guys do not over fill your engines you could blow your engine and its also a big loss of power if the crank has to spin through 5w30.I have a dodge so I learn to be cautious with everything cause they have a hard enough time staying together on there own.


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## bucky6981 (Feb 13, 2005)

i am willing to bet that the notorius gm 4.3liter valve seals leaking has alot more to do with that stuck valve more than 2qts of oil. did the engine smoke a little every time it was started?


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