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oil smells like exhaust

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Old 07-08-2010, 05:02 AM   #1
69SSC5
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Default oil smells like exhaust

what makes my oil smell like exhaust?
I tore into the motor a few days ago to change the injectors, while i was in there i noticed that my lower intake manifold leaks a tiny bit where the manifold meets the block. so i took the lower manifold off and am in the process of cleaning it. While i was doing this it got me thinking should i be changing my head gaskets since im this far and dont want to do this whole thing twice? i know i should of compression checked it before it tore into it but i got overzelouse and forgot to, i have never had any head gasket issues that im aware of but my oil has always smelled like exhuast, was wondering if a leaking head gasket causes this or if fixing the leak in my intake will correct the problem????
106,000 on stock motor
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Old 07-08-2010, 04:32 PM   #2
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nobody knows????
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Old 07-08-2010, 04:39 PM   #3
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Trying to figure out what exhaust smells like. Is it a rich exhaust smell? Are you smelling gas?
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Old 07-08-2010, 04:42 PM   #4
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no its not a gas smell its more of a burnt gas smell,,, thats why i said it smells like exhaust, like burnt gas or maybe a burnt carbon smell is a better was to put it.
i dont know if it is anything but i have always noticed the smell
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Old 07-08-2010, 05:10 PM   #5
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If the plugs look ok, if there is no oil in the water or vice versa and the car runs ok, don't worry about it. Changing the head gaskets without a definite reason can be a lot of work for nothing.
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Old 07-08-2010, 05:40 PM   #6
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pulled all the plugs, they look good and it was running good with a few exceptions that are not the head gaskets, so i guess i will leave it be, thanks for the advice
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Old 07-08-2010, 07:07 PM   #7
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When was the oil last changed? Is it dark? Could just be old oil.
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Old 07-08-2010, 08:11 PM   #8
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its new oil,,, i have owned the car and only put a few hundred miles on it and have changed the oil twice,,, the oil has always smelt like exhuast.... i think the car sat for a really long time before i bought it... when i tore the lower intake off the block i noticed alot of gunk build up (i mean alot, 1/4 inch think or so of gunk) behind the rods of the #8 cylinder... funny thing was there wasnt much gunk build up anywhere else but behind the #8 cylinder rods... wierd
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Old 07-09-2010, 12:51 PM   #9
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Sounds like the previous owner didn't change the oil often enough. Be sure to replace your PCV valve if you haven't done that yet.
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Old 07-10-2010, 08:05 PM   #10
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You might have a cracked intake manifold base, and the egr passage could be bleeding into the lifter valley

OR............

you could have a sticky egr valve, or a sticky PCV valve, so when you nail it or use a lot of throttle, the EGR flooded manifold vacuum gets down near zero PSI and the exhaust gas flows backwards through the PCV for a split second into the top of the rocker cover.
At that point, it's a gas, not liquid or heavy vapor, but it would carry a smell with it.

Make sure the egr solenoid vent tube foam filter hasn't just turned back into a sticky substance, shutting off the release path of the EGR solenoid vent. After all, it's almost 25 years old, and foam does not do well with age and heat.

Last edited by coupeguy2001; 07-10-2010 at 08:40 PM.
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Old 07-12-2010, 12:25 PM   #11
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Default Me too!

Mine does too! 94 LT1 car. This has always been something I worried about. Previous owner had the car tuned and to what specs, I don't know. Been repairing so many other issues that I have not had time to look into getting it properly tuned to the current modifications. I believe that it is running rich though!
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Old 07-12-2010, 06:25 PM   #12
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Quote:
Originally Posted by coupeguy2001 View Post
You might have a cracked intake manifold base, and the egr passage could be bleeding into the lifter valley

OR............

you could have a sticky egr valve, or a sticky PCV valve, so when you nail it or use a lot of throttle, the EGR flooded manifold vacuum gets down near zero PSI and the exhaust gas flows backwards through the PCV for a split second into the top of the rocker cover.
At that point, it's a gas, not liquid or heavy vapor, but it would carry a smell with it.

Make sure the egr solenoid vent tube foam filter hasn't just turned back into a sticky substance, shutting off the release path of the EGR solenoid vent. After all, it's almost 25 years old, and foam does not do well with age and heat.

thanks,,, i have the intake off and i inspected it for cracks and it looks good as far as the eye can see...

where is the egr solenoid vent tube foam filter?

also any idea as to what would cause an oily gunk build in the engine valley behind the #8 cylinder rods?
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