mstrpth

gmc valve seals

66 posts in this topic

If your piston rings are sloppy or the cylinder wall is scored (or rings broken, rarity) you will hear air coming out of the crankcase because it's leaked by that failure.  Every cylinder will leak a little, the key is to focus on the low cylinders and see what you find.  Then compare that to a high cylinder.

 

what kind of pressure should I run?

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I dunno, I've always put shop pressure which varied between 175 to 90 psi.


 


Wet test it though, just on the low cylinders and a high cylinder for comparison.  I think it's mildly sick...IMO your spark plugs should have shown carbon if the rings/wall was bad enough to loose compression and burn oil.  You seem to be in no man's land...


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these are the plugs I pulled out when doing the seals. The threads look dirtier in the pic than they are.


 


and yes, I set them on the first thing I seen :)


 


this is from the right side with front at the top


 


gallery_83_4_54011.jpg


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wanted to give a quick thank you to everyone that's given time to this thread! i'm still learning when it comes to diagnosing problems and may ask stupid questions or not see something that may be obvious to someone else. i'm grateful that this board is willing to help without to much ridicule. Most sites are not that way. :cheers:


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wanted to give a quick thank you to everyone that's given time to this thread! i'm still learning when it comes to diagnosing problems and may ask stupid questions or not see something that may be obvious to someone else. i'm grateful that this board is willing to help without to much ridicule. Most sites are not that way. :cheers:

There is no such thing as a stupid question.  Now, the person asking the question....;)

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wanted to give a quick thank you to everyone that's given time to this thread! i'm still learning when it comes to diagnosing problems and may ask stupid questions or not see something that may be obvious to someone else. i'm grateful that this board is willing to help without to much ridicule. Most sites are not that way. :cheers:

Not sure I helped much, but...

Thank the membership! We have a small crowd, but we're good people and like to help. :love:

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update - haven't looked over the internets yet but..


 


while replacing the alternator I had to pull the intake hose away from the throttle body. I didn't check this before due to having a dry air filter and dry pcv vent tube. keep in mind this truck doesn't have a pcv per say.


 


a quick search pretty much shows to clean pcv system. I did that when replacing valve seals. At that time the vent tube was dry and pretty clean.


 


gallery_83_4_278056.jpg


gallery_83_4_190033.jpg


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But how much blowby do you have?  Doesn't blowby enter the throttle body via that hole visible at the 10 o'clock position looking into the throttle?


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Wait. Explain to me again how this oil is getting in the intake? 

Is it the top left hole I see at the TB that runs to a PCV that is basically an open line with plate in the valve cover to supposedly keep oil out?

Maybe you can have mike fab up a real PCV in the cover if it is your issue and tune the truck (because restricting PCV will cause it to need a retune).

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update - haven't looked over the internets yet but..

 

while replacing the alternator I had to pull the intake hose away from the throttle body. I didn't check this before due to having a dry air filter and dry pcv vent tube. keep in mind this truck doesn't have a pcv per say.

 

a quick search pretty much shows to clean pcv system. I did that when replacing valve seals. At that time the vent tube was dry and pretty clean.

 

gallery_83_4_278056.jpg

gallery_83_4_190033.jpg

 

That's probably from the EGR which exits near the throttle body. (that silver hose on the passenger's side.  Seafoming it will help.

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