I have a 2002 with 88,000 miles on it. I've had oil loss issues for a while now but basically ignored it. I lose about 1qt/1k. Anyways I brough my car into a shop to get a wheel bearing replaced and decided to have them check the motor out. Dry compression came back around 180 per cylinder. Then they ran the wet test and it jumped to about 240! This happened for all cylinders, about the same numbers. The mechanic says my rings are shot and to just deal with it and keep adding oil when needed. Anyone with any experience with this issue let me know what you think. A rebuilt motor installed is probably, what, 4500-5000 right? Not worth it...thanks

shaz

 

just pick up a low mileage motor and have that swapped in. should run you about half that. or rebuild your motor instead of buying a rebuilt motor

 

I dont understand how motors work that well but this doesnt really make sense to me. All of the rings are bad yet its creating 180 pressure? Isnt the point of doing a compression test to find a bad cylinder, then run the wet test on that cylinder to see if the pressure comes up? If they were all bad wouldnt they all register lower pressure that 180?

If I do have to go the new/rebuilt or rebuild motor route where's a good place to find one?

thanks

 

to be honest, 240 sounds too high. he probly just got too much oil in there and it increased the compression number. as far as i have seen, 180 is about what everyone gets on a healthy 3.5. obviously, if youre burning oil its not healthy, but the rings can be bad and still have good compression, since the oil scraper ring, or w/e you prefer to call it, doesnt carry compression

 

I'd just go with a low mileage used engine if you decide to replace yours, saw one with 42,000 miles with transmission for $1300 and another (transmission included also) with 57,000 miles for $1000 on my local craigslist.

 

just picked the car up. the guy says that the increased pressure is creating blowby? the oil is being forced up to the PCV, does that make sense?

 

Really, I would just regularly check the oil level on an engine that uses oil. Do it every week or when you fuel up. If it runs fine, then leave it alone. You can buy a lot of oil over time for the $1000 or so that it will take to cure this problem.

 

i say just add oil as needed... a quart every 1k isnt gonna kill you.. and at $5 a quart, it'll be waay cheaper over the lifespan of the car to keep adding oil than to buy a new engine and pay to have it swapped in... or even pay to have new rings put in your old engine

 

Check on shortblock prices! A whole engine isn't needed @ 88,000 miles. Are you the original owner? How long did you break-in your engine, when you first bought your car? What kinda oil did you use most of the time? How often did you perform oil/filter changes?

 

I agree, at least search around a few junk yards in your area an see if you can catch a good low mile motor. Run a carfax on it to prove mileage. And in the mean time put in the oil as needed. Evantually youll find a good deal and you can buy it.

 

True but it would still be cheaper to go with a low mileage used engine than have the old one pulled, torn down, shortblock rebuilt, re-assembled and re-installed vs just swapping in another engne. Only problem is even with low mileage, it is best to hear a used engine run and do a compression check before doing all that work. On the plus side of a rebuild, if money allows, you can bore the block and stroke it for more displacement.

 

^^

But,

I'd rather do some top end work. Not that it is better, but stroker kits & pistons for th VQ are insanely expensive, more so the stroker kits.

For used engines www.car-part.com.

 

That's all nice and dandy! But the turn around time is much quicker going with a ready to install shortblock or if you can afford it... longblock assembly! I've done all that tearing down and rebuilding on several cars! Overall less time and money with a rebuilt S/B or L/B! Yall probably have the same concerns I had...using what kind of parts (rings,seals,bearings,etc)! Sometimes it's cheaper and far more efficient
getting a rebuilt S/B and upgrading the rod bolts, rings and bearings to your liking(brand) after you do a little dimensional inspecting the of S/B assembly components!

 

I built a couple short blocks for my Chevelle so I understand what you are saying. For fast turnaround, you need an already built shortblock and I am not sure how readily available they are for our cars.

 

thanks for all the suggestions but the issue thats bothering me is the fact that I'm told my rings are bad because my psi went from 190 to 240. That just doesnt make sense, isnt a 190 reading really good? How could I have bad rings and get compression results that high?

 

Perform the test again. 190 is fine, but, in order to keep the consistency, perform it again.

 

The FSM/Haynes manual I referred to says 185 psi is standard 142psi is minimum and the most important thing, psi differential between cylinders is 14 psi! So I don't think it's your rings either. Get a leakdown tester and your find your leak source I'm sure it's one of those crystalized valve stem seals more than likely on the intake side.
That wet test didn't really prove anything was wrong, it just seals everything up. So there will an increase in PSI. Make sure your testing each cylinder with the same amount of compression strokes to get a consistent actual reading. This will show if there are any strong cylinders and if there are any weak cylinders. Otherwords if you crank one with 6 compression strokes crank them all with 6 compression strokes.