This may sound dumb, but... What exactly do they do? I tried searching for info but couldnt really find anything, so if anyone has a link or just could give me some in depth info that would be great. What could cause them to need to be replaced? Would running a lighter weight oil in a turbocharged engine have any effect on it? I ask this b/c mine need to be replaced (compression check showed that they did) and the previos owner was using 5w30 or something like that. Also what would happen if I were to drive the car for a while without replacing them as long as I watched the oil level?

 

This is something I'm currently dealing with.

How Stuff Works .Com is VERY useful for info like this.

Piston rings keep combustion gasses from going past the piston, and the oil from entering the cylinder.

"Piston rings provide a sliding seal between the outer edge of the piston and the inner edge of the cylinder. The rings serve two purposes:

They prevent the fuel/air mixture and exhaust in the combustion chamber from leaking into the sump during compression and combustion.
They keep oil in the sump from leaking into the combustion area, where it would be burned and lost.
Most cars that "burn oil" and have to have a quart added every 1,000 miles are burning it because the engine is old and the rings no longer seal things properly. " -HSW.com

Depending on how bad yours are, you may be fine driving it for a while. I also have a bad head gasket, which is causing my car to overheat, so I HAVE to change my gasket, and while I'm at it, I'll do the piston rings. Neither is a small job, but you have to remove the head to get to the rings, so it makes sense to do it now rather than later.

While I knew it would be $200+ in parts to do this, I wasn't quite counting on all the tools I would need to buy. But...I'll have them for next time (;

I doubt that using lighter weight oil would cause them to wear, but anything that is easier to get past the worn rings, will result in more loss of oil.

If you intend to keep the car, or can't afford a newer one, it's something that should be done if you have the time. If you don't forsee keeping the car long, and can keep an eye on the oil, it's probably not worth it.

 

Thanks for the info, I tried looking on HSW but I guess I just didnt look hard enough. I do plan on keeping the car, I just want to be able to drive it. I guess Ill just wait it out since I still have another car to drive in its place. I dont plan on doing it myself, Ill be having a local DSM mechanic do it for me. I can handle little things like slave cylinders and such, but when it comes to taking the head off of the car Im still a little scared. Thanks again.

 

I'm doing mine partly because I won't junk the car, can't drive it the way it is, and now, mostly because I know very little about the engine. So I'll learn.

 

piston rings,
alright there is three of them unless you have a heavy duty truck
but the bottom one is the oil one all of them play some part in the oil lubrications but the bottom one plays the biggest as if you look closely at it there will be spaces in between them for oil to go through. then the top two are just to keep compression in for the piston when it is on the compression stroke. That is pretty much piston rings there is a lot more info on them but that is probably all you are looking for

-garrett

 

Don't you have another car? I've reached the point where I just say "screw it" and dive into pretty much anything even if I don't think I can do it. Got the clutch done this way. On the other hand that probably was a source of some of the problems I'm having now. If I had another car to drive I wouldn't care at all, though. As it is if I can figure out a way of getting around locally without my car I don't really care, I'm thinking about getting a motorcycle, great on gas and relatively cheap for a used ninja 250. As for the car, if you do the repair and it doesn't turn out right, and then you can't figure out what is wrong with it afterward, at that point you should get help from somebody who actually knows what they're doing. (like I'm about to do )