Compression Still Low In 1 Cylindar! Help

blownsc

Registered User
Well I figured it was the head gasket so I replaced it, but i still have low compression to the tune of 90psi compared to the 145 in all the others!! That's w/ a brand new gasket and arp studs. I though it might be cylindar rings, but i have gotten no smoke out the exhaust which should happen since oil would be suckind into the cylindar on the down stroke. I added oil to the cylindar and the compression rose to 120psi which rules out a bad valve seal. I'm thinking cracked or warped head. Also, prior to this I have been getting a good deal of coolant in my oil. I have not run it enough since the new hg to see if it's still leaking. I'm not sure where it's comming from but it's not the oil cooler. What do you all think? I'm getting ready to buy new heads but I want to make sure that's what's wrong.
Thanks,
Kyle
 
what exactly does a leak down tester do? Yeah, I get a little smoke and all kinda of bad shit comming from the dip stick tube. where can i get a leak down tester? how is it used?
 
nevermind I looked it up. I'll see if i can rent one and try to track down someone w/ an air compressor. Would a piston ring explain the coolant in my oil though? I don't get that one....
 
nope, but i'm still getting low compression and that's what's troubling me. It also overheats after about 30min of driving
 
did you have your heads checked and surfaced when you did your HG's? Remember that your heads are aluminum and your block is cast iron. Also could be a cracked head, I had a cracked head last year when I blew my HG's.

Always, always, always get your heads checked and surfaced when you remove them from the block. If you did not have this done, I would put my money on that.

Also, if memory serves me right, if your compression went up when you added oil to the cylinder, I think that means bad compression ring, but I don't think that would cause overheating. Although, a bad seal at the HG's would.
 
Don't bother looking for a leakdown tester, you already have the answer. The increase in compression when you added the oil points to bad rings. The blowby and PCV fouling confirms it. Sorry.

Steve
 
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