First 911

[GT4]

Is the RMS a worry on a 997 of this age my2006 20kmiles? Should it have been done as a matter of course at the major OPC 18k service?

The owner seems to be saying RMS was a 996 prob not 997?

Thanks

Sam

The RMS affects 996 and 997 (generally non-GT1 blocks - ie not the GT3/Turbo - but even they are not immune).

Almost every car has a "rear main seal" - it's just the seal at the end of the crankshaft before the gearbox mates. If a leak does occur it is mostly annoying and can be remedied at the next clutch change for £20-£30.

In the Porsche, until the drivetrain is completely re-oriented etc (ie never), the RMS issue may always exist. Yes the seals improve, the engineering tolerances of the castings and their associated assembly/rigidity of driveline structure increases, but the way the heavy engine is slung out the back after the gearbox and drivetrain poses significant stresses.

However, the RMS is not an issue for most cars, on those it is apparent, it is generally not significant and merely results in a slightly annoying drip. Of course there are times, as with every car and every component, that you get a completely failure and the seal unseats or falls apart over a long time or excessive use or poor installation or random quality defect.

Then it can drop the whole crankcase of oil, which is both very messy and obviously leaves the engine without cooling and lubrication oil. As with most cars there are plenty of sensors to indicate this problem or ensuing issues. In some ways it is the possibility of a slower release and then clutch contamination that is more likely/insidious.

It is certainly not a service item. In fact consensus is to "let sleeping dogs lie" in the sense if it ain't broke, don't fix it.

If it is misting/wetting, simply replace at next clutch. Very rarely are RMS replaced in isolation. Only when an OPC can get some free warranty money do they tend to push for otherwise untimely/unnecessary replacements.

For its resulting "infamy", Porsche did themselves no favours by submitting an RMS warranty claim every five minutes (it's alot of labour money for old rope for OPCs).

For first gen 996 cars, it may have been more prevalent initially and less so on the later models as later models had better/improved seals. These new seal designs were then retrofitted at any time the older models came in for RMS work. Fundamentally there is no difference in the actual case castings.

In the 997 RMS issues have been lessened by further revisions (including teflon flanging) to the seal and again these are now the standard RMS to retrofit to 996.1,996.2,997.1 etc.

In fact some independents swear by the beefier Cayenne RMS retrofit to the 911 (yes even the Cayenne has an RMS).

 

[BRS]

Thanks for the comprehensive answer :thumb: