ex177

ProfDNS

Scrap yard. I'm not kidding.
Low compression + burning a LOT of oil (for these cars). If you want to keep it the car, you could do a LDK rebuild, or turn it into pop cans.

That engine is done.

ex177

Slowbalt2000

iTrader: (1)

06cobaltss/ss

also check the turbo to make sure that its not blown. mine is on its way out and burns some oil underboost. check for any shaftplay. may even find the oil at the turbo if its bad enough.

ex177

ex177

exninja

iTrader: (1)

I'd do another compression test and double check the gauge you're using (best get a second opinion) before calling it a goner. 150ish is typical for lnf so you're not horrendous. Excessive oil in the intake is a sign of blowby but the PCV system in these cars sucks oil when they're mint so it can be hard to tell.

C0balts5

Sounds like your rings are carboned up. They make g.m. top engine cleaner that your can run through the intake and put maybe a small cap full down into the spark plug holes and let it soak overnight and then crank it without the plugs it so you don't hydra lock it. The oil on the intake side of the turbo sounds like the pcv valve is clogged and might be stuck open and sucking up oil, I would pop a new pcv in as well. I work for acura and some of our cars have oil consumption issues that we usually resolve by adding half a quart of atf to engine oil when we change the oil, that surprisingly works and the car will slow down on oil drinking cause the rings will free up but I don't recommend doing that in a turbo car. Your right at the limit of cylinder variation with your compression readings, I think it's no more than 15 percent variation from the highest and lowest cyl reading. They consider that within spec. Your not going to have high compression readings on a turbo car so I would do the g.m. cleaner, dump some in the cylinders and let it sit overnight. Then go drive it to burn out the residual and change the oil and PVC. I have 116k on my 08 ss tc that's been boosting 23 psi for almost 100k and it's not consuming oil. Mainly probably because once a year I do a fuel induction service and I change the oil every 3k on the dot

Slowbalt2000

iTrader: (1)

ProfDNS

I'd take a borescope down into the heads themselves as well. If it is oil sludge, I would advise like above - top down cleaner, and change the oil again shortly after that.
I've also seen many people try ATF to do the same for really bad sludge but I would do research first.

C0balts5

Especially if you listen to the maintenance life gauge. They want you driving on average 7k on oil with a turbo, gasoline direct injection car. Old school all they way. Oil is cheaper than an engine or turbo

63 Nova SS

iTrader: (3)

I have a lnf and the last time I checked compression (2,000 miles ago) I was from 155-158 on all cylinders.

C0balts5

Never did a compression test on mine. Not using oil and has no noticeable power loss. The cheaper route is the engine cleaner and pcv valve and hope it gets better.

ex177

C0balts5

No problem. I hope it works well for you. I've seen that cleaner breath some life and compression back into engines. The combination of the gasoline direct injection and the possible pcv valve issue slipping oil probably has those rings junked up so they are not springing back out like they should. From what I understand these engines are pretty stout and hold up pretty good. I see one roaming around where I live every now and then that had 170,000 miles on it last time I talked to the guy and that was 4 years ago and I still see it, his was bone stock though.

ThePanduuh

iTrader: (3)

this is unrelated to low compression but GM top engine cleaner is ****

cw383

iTrader: (6)

Definitely try another gauge. I had a fit when my new engine wasn't showing good compression even after 10k mines, thinking rings weren't breaking in. Here the brand new compression gauge I was using was about 40PSI off. 120/cyl is not a death sentence, although not exactly healthy compared to the rest of them. I drove a car on low compression on 2 cylinders for a year before I popped my new one in because I simply didnt have time. If you take it easy you might be fine for a good while. Mine ended up being fractured ring lands being held perfectly in place by the rings. 75psi lol. Also maybe unrelated here, but keep in mind camshafts can reduce compression a good bit too if anyone ever messed with the motor, although it would be in all the cylinders, not just one.

cw383

iTrader: (6)

That is a thing of beauty! Did you use brushes ( if so what kind ) or shells? I blasted mine last time, but I may try brushing next time. Be interesting to see if the 60lb 5th injector helped any.

steelmesh

Your post is implying GM top engine cleaner did that to the intake, I call BS. Please provide a source for this.

C0balts5

The g.m. cleaner will help the valves as well. If you think about it sometimes valves can cause low compression and or misfires because of the carbon build up on the valves due to the direct injection and the valves not sealing 100 percent, I have not seen them come out that good but it's a better start than going in straight for the kill with a new engine.

Sport Red LNF

^^^This

It sounds like the rings are severely carboned up and stuck in the ringlands. Run a can of Seafoam through it and add ATF to the oil and see what happens. You have nothing to lose at this point, might as well try to see if you can restore compression.