Compression test results what do you think?

[85GPLef41]

Have you done a leakdown test? I tend to trust them better then a compression test. Also try squirting some oil in the low compression cylinders. If the pressure goes up after squirting oil in them then the rings could be bad..

 

[ERIC87442]

now the engine only has 48k on it so idk if would say rings would be bad really would ya?

 

[86Olds442]

Forgot to ask that... but even cold it should still have halfway decent compression.

yeah it should, mine had 150 on all 8 cold and dry test. but some engines with some miles might need to be warmed. i would get it to operating temp. shut it down them disable ur ignition to check it again. then after that test. dump a couple squirts of motor oil in each cylinder before u hook up the compression guage to it. let us know how much if any the numbers come up.

My 86 also got 150 each on a cold and dry. 120,000 miles on it but the heads were freshened up. Book wants 110 minimum per cylinder. 4 and 7 would concern me too.

 

[carmangary]

My 260 only has 90-110 dry compression. Runs fine once it starts.

 

[86Cutlass383SR]

If one of the rings is broken it can lower your comp reading. It's not so much about the total reading right now, it's about all being the same. You want all to be within about 5% - 10% of each other.

Put about a teaspoon of oil in each cylinder and recheck quickly. As was said, the oil will temporarily seal the rings if that's the problem. If it increases, ... you have ring problems. If they stay the same, then you have blown head gasket, bent/broken valve, or cracked head problems.

Then it's time to at least pull the heads. Have them checked and look at your old gaskets for signs of leaking.

If it still runs, let it warm up enough to open the thermostat and watch the anti-freeze in the radiator with the cap off. Is it surging up and down? If so, then you are getting compression pulses in the cooling system from either a cracked head or blown head gasket.

 

[85GPLef41]

now the engine only has 48k on it so idk if would say rings would be bad really would ya?

i would at least do that to rule it out. I would hate to spend $$ on the heads and still have that issue.

 

[86Cutlass383SR]

I agree. I'd hate to even spend the time and money doing head gaskets only to find out nothing I did fixed it.

 

[ERIC87442]

if i take the oil cap off it poots smoke out the filler neck

 

[bjohn07]

clean out the pcv valve.

 

[ERIC87442]

i shook the pcv valve and it still rattles and all that good stuff and the little thing still moves but i could replace it, i get oil up in my air cleaner area tho