What is an RMS failure? - Page 1 - Porsche General - PistonHeads UK

I'm aware it's an oil leak, but where exactly in the engine and how serious is it? Is it something that you can continue to live with, or is it an absolute must fix priority? Is the RMS issue common to just the 911 or is it simply an issue with all Porsche engines? Finally, is it a massive job to put right, what would the typical cost be?

RMS = Rear Main Seal. Oil leak from the back of the engine, usually starts as a slow weep. Unique to the flat 6 engine. OK to leave it for a bit unless a lot of oil is being lost. OPCs always recommend getting it fixed right away. It's not all that expensive to fix but most people have a new clutch fitted at the same time so probably about £1300 with that. On our Boxster it was £1900 for major service, clutch and RMS.

Where do I look for the tell tale signs? (on a Cayman S).

Oil on your garage floor under the back of the car (almost as far back as the exhaust). This would indicate quite a big leak which probably needs fixing. But usually just a wet patch at the back of the engine (our was like this - it's often only spotted during a service) which you can't really spot without getting it up on ramps. If it's like this there's no hurry to get it fixed (or so I'm told). BTW the prices above were at an OPC. If you have no Porsche warranty it'll be a lot cheaper at an independant. I'm sure someone will chip-in with a pic of a leaking RMS before long - I'm sure I've seen one on here in the past. Edited by telford_mike on Sunday 6th September 15:18

If only there was a SEARCH facility it'd be so useful.

X-UFO said: If only there was a SEARCH facility it'd be so useful. but its as useful as a tub of viagra at a lesbian orgy.... The rear main seal is between the engine and gearbox. On most cars it is a weep of oil - dead center under the car directly between engine and 'box. So long as it stays as a weep or a slight drip, and so long as you keep an eye on the oil level it will be fine. If you are getting a new clutch it should be about £30 extra charge to be fixed. Likewise if getting it fixed you may as well throw in a new clutch as the labour is paid for. In THEORY if it is bad enough it can foul the clutch and cause slippage - but I've never actually heard of anyone who encountered this (and I know at least 2 people who have had an RMS weep for over 5yrs, and one of those over 80k miles)....any other stories about damage are just that - stories, and I've never heard of anyone sustain any real damage from an RMS weep. My opinions on it: 1. Its an oil leak - porsche' throughout history have leaked oil, the 964 was notorious for it...cars leak oil all the time, but in most cases its ignore and causes no harm so long as oil levels and pressure are unaffected....the hysteria over it is nonsense 2. It came about from warranty claims - the OPCs noticed it was occurring fairly regularly and its an easily paid for warranty job for them - they get cash for sorting it - so they play up the severity to get the customers to demand the job - and due to rumours and internet chat it whipped up into a frenzy of "major design flaw" and it snowballed and we end up where we have a minor oil leak bringing down the reputation of what statistically is a reliable engine.

Don't let anyone tell you the GT1 block is immune to RMS failures. It isn't. £1100 for mine to be fixed at an Indy. (with spark plugs renewed, and the clutch was fine)

It's a minor oil leak which means you put newspaper down in your garage if you're bothered. Makes not a jot of difference - you live with it until the clutch needs changing.

Mine went from nothing - weep - drips on floor within 2 weeks.

and surely not actually unique to porsche? It's a crankshaft oil seal, most engines have one (or two) of. It's a design specific to the way the porky engine is designed, but it's just a crankshaft oil seal. It has gained a folklore weight of its own though partly as it's expensive to fix in its own right. Bert

Soovy said: It's a minor oil leak which means you put newspaper down in your garage if you're bothered. Makes not a jot of difference - you live with it until the clutch needs changing. +1 Mine was 'weeping' for 18 months and the car went through almost no oil outside of services. It really is a non-issue but is very common. When the clutch needs doing, pay the extra 30 quid to have it sorted, if the clutch doesn't need doing, wait until it does (unless, of course it is pishing oil out in which case it is no longer a minor issue!!!)

So what about the IMS leak..... This is the result of an RMS leak (996 cab....):

If that's from one parking session that's an RMS that should be done. A few drops from time to time is nothing to worry about.

With regard to the previous picture showing some very black gunk on the floor of a trailer. I would be more than worried if the oil in my engine had become so carbonised that it looked like black sludge!!! I would hazard a guess that an oil change was long overdue (if not in mileage but maybe in time?) Could this perhaps be a contributing factor in the demise of the oil seal?

Hi Agree with the above. We've not yet had a RMS leak which has caused problems other than if someone has a very nice driveway. The majority we see are more weeps which may occassionally lead to a drip every blue moon. Sometimes they're a little worse but in no danger whatsoever of causing any further damage unless it gets much worse or the owner never tops up his oil. As mentioned above, in these cases we also advise to wait until it gets much worse or do it when the clutch etc is due. We've had a few IMS bearing failures leaving the same sort of mess as on the pic above. Grant

Cheers everyone, many thanks. Have learnt that my car has had the RMS fixed and new clutch installed at it's last service (2000 ish miles ago), so all good !!

I've had my Boxster S for six years or more. There's never been the slightest mark of any fluid under the car. We have THREE DRIP TRAYS underneath the sodding Chimaera for the various weeps and leaks...we just keep topping it back up!

Well if it helps my 997TT had an annoying oil drip from the rear (right hand side just behind and to the right of the exhaust). OPC had it whilst on holiday and claimed it was the oil scavenger pump seal which was replaced and bugger me within a couple of days its doing the same!! Now having to book back in again...

My new RS60 is leaking oil and Silverstone diagnosed it 2 days ago - the Cam cover was not sealed properly from the factory and needs to be taken off and resealed. First time the technicians have seen this. It is a slow drip and they told me not to worry, plus it's under manufacturer warranty so I'm not!

Sorry to dig an old thread up but is this a RMS leak ? It's on a car I went to veiw 2006 c4s manual