What causes Piston Rings to fry/ go bad, and get fuel in your oil? Also, how much is it to be repaired?

A plugged exhaust or converter will force exhaust by the piston rings along with unburnt fuel. The fuel will wash oil from the cylinder wall causing wear. Too rich of a mixture due to a bad O2 sensor is another cause.


If your rings are bad the cylinder walls are probably damaged as well. By the time you pay the machine shop to bore it out and buy over sized pistons and rings, not to mention removal and installation of the engine, you can probably buy a used engine and have it installed for less than you can fix the old one.


If it was a plugged or restricted exhaust or converter that caused this, make sure you repair it or the same thing will occur.What causes Piston Rings to fry/ go bad, and get fuel in your oil? Also, how much is it to be repaired?
piston rings will fry if you are overloading your engine alot, hot rodding it or pulling very heavy loads. Not changing your oil often enough. Or just alot of miles on the engine. Those things are thin and they do wear out. Most 4 cylinders will last 120,000 to 150,000 and V6- V8 up to 300,000 depending on care.





But basically depending on engine and accessiblity you are looking at atleast 10 hours book time. Most shops charge 100 an hour for engine work.





The fuel in the oil is easy, piston rings seal the combustion chamber without them you will get oil and fuel mixed.What causes Piston Rings to fry/ go bad, and get fuel in your oil? Also, how much is it to be repaired?
it can be any number of things. a common one is modifications to the engine ECU (computer). Those $20 ';super chips'; you see on eBAy do that a lot, a freind of mine ruined his mustang engine with one of those, twice. depending on the car, I'd say it's at least a $1,000 job, if there's no other damage.
leaking injectors could do that, diluting the oil and diminishing the lubrication quality.