Questions about Rear Main Seal

[bigwatts]

Greetings All,

First time post here. I joined the forum a little while back and have spent many hours finding out information I never knew about my boxster.

My question is as follows:

There seems to be a lot of issues with rear main seals. I recently purchased a 97 one-owner boxster from an individual. It has 78K on the clock. I had a pre purchase inspection done and my mechanic did not notice any oil leaks. What causes the Rear Main Seal to go out?? Is it something I need to concern myself with?? The original owner said it was never replaced to his knowledge and I can't find anything about it in the service records I have. When shopping for my boxster I found some similiar vintage cars that had the RMS replaced at 60'ish K. From reading this forum I also notice that the clutch should be replaced when the RMS is done. How muct time can you expect to get out of a cluth on these cars. I have owned many older german cars including porsches. My 968 had 155K with the orginal cluth...and it had no problems at all. BMW's with even higher miles. Just thought I would ask. The clutch seems very strong and the tranny shifts like butter.

Thanks in advance for your help.

[RandallNeighbour]

Do a search here and renntech.org on "RMS" and/or "Rear Main Seal" and you'll see tons of info on it. Don't sweat it though. If you see dripping, get it looked at and don't worry or fret over it if you don't see dripping from the center of the car near the engine compartment.

Clutch wear has a great deal to do with how you drive your car and how the last owner(s) drove your car. If you don't bury the clutch all the time at stop lights and dump it all the time to attempt to light up the rear wheels on takeoff, they can last a long time.

Any time you're in the neighborhood of the clutch in any kind of car repair, you should change it though due to the high labor costs involved in getting to the clutch when you need it in the future.

[Ronzi]

According to an explanation in the most recent issue of Panorama, the monthly Porsche Club magazine, the RMS failure is a design problem with the water cooled flat six Porsche engines, including all Boxsters and Carreras to date.
In a nutshell, the rear of the crankshaft is unsupported where it exits the block, and the flywheel and clutch are hung on the end of the crankshaft. Over time, the crankshaft starts to sag minutely, causing the seal(s) to fail, and thus the leak.
According to this article ALL of these engines (except possibly for Tiptronic equipped cars) will eventually experience an RMS leak, it's just a question of when.
There are some redesigned seals that can mitigate the problem, plus some sealer that can help in some cases. If the problem is serious enough, it can require an engine exchange to cure ... temporarily.
The only true fix for this problem is apparently an engine re-design, which is why the '04 and '05 engines experience the RMS problem just like the earlier cars.

PS - Look at Pablito's post "Busted Tranny" for yet another possible result of the RMS problem, albeit an extreme one.

[blinkwatt]

Should I have to worry about the RMS if mine was already replaced on my 99 Boxster at 27k? Is it possible that it could leak again?

[RandallNeighbour]

Yes, it can leak again. Mike Legere (another forum participant) bought a boxster from a dealer here in Houston and developed a RMS leak about 6 months after ownership. He took it to the dealer where he bought it and was told it had been replaced a year beforehand... so they replaced it for the cost of the part, which was $195 or something like that.

I've heard that the Cayenne's RMS fits the boxster and they're using it with great success now, but you have to specifically ask for it or order that part, and it must be handled very carefully. If the rubber is pinched in any way, it won't work.

Now let me put your mind to ease after I've scared the crap out of you with the comment above, which I just had to put in because it's the truth... if your boxster had the RMS replaced before, it probably won't go out for a long time. Mike's issue was unusual, and the dealer said that too, hence the discount they offered.

Blinkwatt, I really want to encourage you to enjoy your car and not worry about RMS leaks until it happens to you, because it may not happen to you at all! When I first bought my 97 box last year I got very worked up over this very issue because I thought "if I had an RMS failure my engine would blow and then... oh my I don't want to think about that!"

From all I've read, RMS failures start as a drip on your garage floor and you have time to fix it before it gushes out and blows your engine. Just keep an eye on your garage floor and enjoy your wonderful Porsche convertible

[MNBoxster]

Originally Posted by blinkwatt

Should I have to worry about the RMS if mine was already replaced on my 99 Boxster at 27k? Is it possible that it could leak again?

Hi,

As stated, they can fail a 2nd time even more. Moreover, the RMS is a Wear Part, that is, it actually makes contact with the spinning crankshaft. Consequently, every Boxster will have it's RMS replaced if it lives long enough - the RMS will simply wear out. Failure at 27k mi. is leaning toward the high side of an RMS failure - the highest mileage failure I've heard about is 36k mi. But, the odds are definitely in your favor, from all reports, there appears to be only about a 5% chance of a 2nd failure. Mine failed at 4k mi. - now, at 24k mi. (and 5 years later), everything is Dry as a Desert!

So, just go ahead and enjoy the Car! Worrying about it is really pointless. Just inspect the underside frequently for any seepage and react to whatever you find. Good Luck!...

Happy Motoring!... Jim'99

[PA986S]

Bought my 01 BoxS with 29,000 on it and an RMS leak (did not know at the time) luckily it had a month of warranty left and the dealer replaced the RMS and the clutch. 5 months and 2,000 miles later and oil is leaking again in the same area...not sure if it is the RMS yet but I hope the dealer covers labor if it is.

[Brucelee]

Yes on the possibility of a repeat RMS.

I once purchased a 911 that had had three RMS repairs under warranty.

However, according to my tech, it is rare to have more than one, but it does happen.

[limoncello]

Quote:
"Consequently, every Boxster will have it's RMS replaced if it lives long enough - the RMS will simply wear out." from MNBOXSTER

Assuming all RMS's will eventually fail, some questions come to mind:

1. Having seen all the posts, how many owners have actually changed the RMS in their car?
2. Was the change in warranty or out?
3. What was the cost to replace the RMS? (Assuming the crankshaft passed the alignment test and it was just an RMS repair.) Professional inputs welcome Brucelee.
4. Any actual engine replacements?
5. If so, what did the engine swap cost?

Just thinking about the long term view of Boxster ownership - my plan is to keep this car for 3 years & swap. The only 2 major systemic ills of the Boxster seem to be the RMS and the jamming top mechanism, otherwise a pretty durable car.

re: Plans - my original plan was 3,000 miles per year for 3 years. Had the car 6 months now and hit 3,000 miles already. It likes to go for drives...so much for planning.

Thanks for any info!

[Brucelee]

I will be chatting with Porsche service today. Let me see what I can find out.