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Mystery Problem with Oil Loss

A friend of mine has a '97 Nissan Sentra and up until recently, it ran fine. Now the car needs to be refilled with 2 to 3 quarts of oil after being driven less than 100 miles. A mechanic looked at the car and said that there were no oil leaks and that the car didn’t emit much blue smoke. After looking over the car a second time, the mechanic said that the number 2 cylinder needs new oil rings and that the job to replace them would cost $2,000.00. How can I ensure that this is the problem and that the repair cost is reasonable? A friend doesn’t believe that oil rings can disintegrate so quickly.

Before you condemn the engine, have the PCV (crankcase ventilation) system checked thoroughly…To check for a problem here, remove the air-cleaner and inspect the entire length of the air intake system for oil residue…if you find oil in the air intake, you have found your problem…How many miles on this car?

You can’t just replace one piston ring…The entire engine must be disassembled to do this repair…There is no light at the end of this tunnel…

Oil consumption of 2-3 quarts in 100 miles without any outward symptoms is very hard to believe. In 1000 miles sounds more credible. In any case, you need a second opinion, and not drive the car much further. Heavy oil consumption will quickly plug up the catalytic converter and add more expense.

He may be right that #2 oil ring needs to be replaced, but I would get a second opinion (engine anaylyis) just the same.

A 1997 car ususally does not warrant a new engine, but a partial rebuild is warranted if the rest of the car is in close to new condition. Where I live, a mint 1997 Sentra sells for about $1100.

Please give us the mileage and the overall condition of the car.

I would get a second opinion of the cause of the oil burning…if that’s what it is. Check your PCV valve as well…it may be plugged up. Depending on the mileage of the vehicle your friend could be right about the oil ring disintegration. If the oil was not changed on a regular basis then all bets are off.

check the pcv/breather system. if that’sok have a compression test (both dry and wet). if that’s ok, maybe a set of valve seals could fix it. if not, shop around for a good low-mileage used engine. is it worth it? that depends. do you want to drive it, or use it as lawn art?

And if it does need rings, it actually needs a replacement engine. Rebuilding engines is a lost art.

Assuming OP has carefully checked for oil leaking onto the ground. The oil has to be going somewhere else, and about the only place it could go is either out the tailpipe, or into the coolant. OP should have their mechanic rule out a possible oil leak into the coolant.