which seal/gasket is bad? i'm about to pull the intake on a recently rebuilt 5.7 TPI engine because of oil "consumption" and in the process of tearing down, discovered oil pooled up on the driver side between #3 and #5 runner. didn't see any on the pass side. had this same problem years ago when it was still under warranty, and believe it to have been the intake gasket. regardless, i'm sucking down a qt of oil every 500 miles or so. supposedly a bad intake gasket there, too. so before i go all the way down to the intake, looking for clarification... plugs are coking up from it and i hate to think what my new innards look like now because of this. which brings up another ? - what can be used to clean the engine now in hopes to at least somewhat remove all the crap i'm thinking is in it now. i'm down to one runner and the intake left to remove, but probably a better idea to get another opinion at the moment. the gasket used on the rebuild was a stock GM gasket, same as the one i used a few years back. anyhow, i'm hoping both issues are due to the same gasket...

 

Between #3 and #5, sounds like sealer was not used on the intake manifold bolts.

I doubt the oil consumption is related to a leaky intake unless its always been using that much oil.

 

sealer was used on all the bolts... and since the rebuild, yes, it has always been using that much oil. almost found that out the hard way. machine shop seems to think it's a bad intake gasket and sucking it in to the cylinder(s).

 

oil in the intake bad pvc valve

 

interesting. so much for those new parts, huh? i'll change that, too. thanks.

 

What sort of symptoms would I experience if my intake manifold had a leak? How would the car be running? 1989 Formula 350

 

well in my case, mine ran fine til the plugs got all fouled up from the oil being sucked in to it. but what kind of leak are YOU talking about? oil? vacuum? water? when i got my intake off, i could see oil residue up the side of the heads where they meet the intake, more so between #3 and #5. i had used GM gaskets on the build, which is the same as i used last time with no problems. they are a crush-type seal gasket... this time i put a thin film around all the ports and bolt holes, so should be good to go. i'll find out in a few days when the rest of my stuff gets here...

 

I'm thinking vaccum leak.

 

yea, that'll cause some run-ability problems...