RMS?

OK - I have some real noob questions. I did some searches and I don't seem to see answers on these: 1) What does it stand for? 2) How can you tell if your RMS needs replacing? 3) What is the tech behind it sucking so bad? ie why can't Porsche fix it? Flame if you like - I'm just looking for some info I can't seem to find.

1)Rear Main Seal = RMS 2)If you see oil dripping from the bottom of the engine (where the tranny and the engine are attached) it could be the RMS.. 3)I am still looking for the answer of that one!

It won't be leaking very much, so it's not too big of a deal. You can wait to fix it when you need a clutch replacement so labor is cut way down. They are using a 997 type seal on it now I believe, and it works - so it's not much of an issue.

Also suggest you read the following online article: http://www.renntech.org/forums/index...e=post&id=3223 And pick up the June copy of excellence magazine where there is a good write-up in the letters section.

Thanks for the info guys, I'm not sure I understand why so many 996 owners had engine problems after reading the article that cdodkin provided a link to. If the RMS was going and owners checked their oil occasionally, wouldn't they notice low oil and top it up, then have their mechanic have a look at it? Or could the RMS just 'blow' and lose all oil in the middle of a drive?

The crankshaft is known to rupture the poorly manufactuered seal at the end of the casing, causing an oil leak which may starve the engine of oil, destroying it.

never seen a rms seal "fail" and drain the engine of oil.

It doesn't happen like that. It is typically a small slow leak. Your best indication you have a problem is a few small drops of oil on the pavement just below the seal.

Many of the RMS engine replacements were initiated by Porsche after they deployed a faulty measuring tool in the early stages of the RMS issue. Not by engines loosing all their oil or suffering any sort of failure. RMS is a slow leak, so slow that many never notice anything. Simply keeping your oil topped up is all that's required to live with RMS. It does not suddenly leak out all over the floor killing your engine!

Just as a counter-point, sometimes the RMS failure can show up as a significant leak that cannot be ignored. In my case, my RMS failed overnight, left about a 4" diameter puddle, and was dripping about 1 drop per hour after my commute to the office (10 minute drive). By the time I got to the mechanic 2 hours later, it was dripping faster, and dropped multiple quarts by the afternoon when they were able to begin working on it. This is very much uncharacteristic of most failures, at least as reported here, but it is certainly one of the failure modes. The presumption on how/why mine failed this way is that the seal had dried out due to significant lack of driving (the car had less than 8k miles after 4 years), so when it failed, it was a catastrophic failure. I would agree that the RMS is unlikely to cause engine failure, unless you totally ignore a major oil leak. The catastrophic engine failures on these engines seem to be either a lower engine chain/gear thing or a cylinder wall crack. Both are very well explained in some articles that have been posted here numerous times, and both are unrelated to RMS/LMS issues. Both of these failures appear to be fairly rare, unlike RMS/LMS leaks, which are fairly common. Oh, and don't be terrified of an RMS/LMS repair, total cost to repair is $1000-1300. And depending on your vehicle's condition, it's an excellent time to replace the clutch, since the majority of the cost of the clutch job is the labor to get there.