IMS, RMS, crankcase bolt leak trivia with pictures

[Domiac]

Hello there, my car is an early 2004 996 C4 Cab, 3.6L, 85k miles.

Good stuff on my DropBox folder: https://www.dropbox.com/sh/p62gwxshg2zath4/0wYS9yrgfv

Engine has not been started for 4 months. Actually it has been on a huge container for 2+ months and just few weeks ago I got the time to start working with my car again.

Just before taking these pictures, note that I did wash my engine and transmission while they were still connected to each other, that might explain the glossy oil spots near my IMS (or not).

Four months ago, underneath the car it looked that I get a tiny amount of oil after I drive around 500 miles, sometimes even a drop of oil to my garage floor if I drive a lot more. The drop comes right to the spot which usually indicates RMS/IMS leak. Then again, my AOS has been spitting lots of oil out from the connectors and the drop might originate from there too, impossible to say as front left side of the engine near AOS was so full of oil and gunk.

I've changed my oil now twice, both the oil and filter ripped open has looked really really clean but this is based solely on human eye :-)

I'd like to get a few second opinions to my questions, hopefully this thread is usefull to others too.

1) How does my RMS / IMS look in general?

I'd say the leak is reasonably small, most gunk originates from clutch, would you feel the same?

2) Would you change my RMS or just leave it be?

It has already been changed once at some point.

3) What exactly seems to be leaking here?

To me it seems to be the IMS, but strangely enough the bottom part right below the IMS cover was completely clean (just zoom the images and remember that I washed my tranny and engine just before separating them).

4) Which bolts would you change while doing the IMS?

Looking at the pictures, many change bolt numbers 4, 5, 6 and 7, how about you?

5) Curiosity question, what parts are not original?

My RMS must be new as the part number is 997.101.212.00. IMS looks old, part number K.99602401 (?). Also would you also feel that many of these bolts have been changed as they look past year 2004 bolts, right?

PS. I have a new RMS, LN bearing + tools waiting for the installation..

Big Kudos to everyone who got this far, hope you'll inspect my DropBox picture folder too!

Edited March 27, 2014 by Domiac

[JFP in PA]

Hello there, my car is an early 2004 996 C4 Cab, 3.6L, 85k miles.

Good stuff on my DropBox folder: https://www.dropbox.com/sh/p62gwxshg2zath4/0wYS9yrgfv

Engine has not been started for 4 months. Actually it has been on a huge container for 2+ months and just few weeks ago I got the time to start working with my car again.

Just before taking these pictures, note that I did wash my engine and transmission while they were still connected to each other, that might explain the glossy oil spots near my IMS (or not).

Four months ago, underneath the car it looked that I get a tiny amount of oil after I drive around 500 miles, sometimes even a drop of oil to my garage floor if I drive a lot more. The drop comes right to the spot which usually indicates RMS/IMS leak. Then again, my AOS has been spitting lots of oil out from the connectors and the drop might originate from there too, impossible to say as front left side of the engine near AOS was so full of oil and gunk.

I've changed my oil now twice, both the oil and filter ripped open has looked really really clean but this is based solely on human eye :-)

I'd like to get a few second opinions to my questions, hopefully this thread is usefull to others too.

1) How does my RMS / IMS look in general?

I'd say the leak is reasonably small, most gunk originates from clutch, would you feel the same?

2) Would you change my RMS or just leave it be?

It has already been changed once at some point.

3) What exactly seems to be leaking here?

To me it seems to be the IMS, but strangely enough the bottom part right below the IMS cover was completely clean (just zoom the images and remember that I washed my tranny and engine just before separating them).

4) Which bolts would you change while doing the IMS?

Looking at the pictures, many change bolt numbers 4, 5, 6 and 7, how about you?

5) Curiosity question, what parts are not original?

My RMS must be new as the part number is 997.101.212.00. IMS looks old, part number K.99602401 (?). Also would you also feel that many of these bolts have been changed as they look past year 2004 bolts, right?

PS. I have a new RMS, LN bearing + tools waiting for the installation..

Big Kudos to everyone who got this far, hope you'll inspect my DropBox picture folder too!

1. Both the RMS and IMS appear to show different levels of leakage; the RMS is seeping, the IMS flange is flat out leaking.
2. I would definitely install a new PTFE style seal; at around $20, it is a no brainer.
3. The IMS flange is leaking the worst.
4. Probably none of them unless they show signs of a problem. The reason Porsche came out with replacement bolts had to do with the RMS bore concentricity or roundness. Back when they were replacing entire engines due to leaks that could not be stopped, Porsche came out with slightly longer microencapsulated bolts to replace the four in the bell housing area to try and hold the RMS seal bore in a more stable position during engine operation. These were typically applied to the early M96 engine's that had shorter bolts from the factory. Unfortunately, while they may have stopped the leaks in some cases, Porsche eventually figured out that the real issues were out of round RMS seal bores, and variances in the concentricity of the flywheel flange on the crank. To help the dealers decide which engine's could be saved by retrofitting rather than replacement, Porsche released special tool 9699/1, which became known as the "Go, No Go gauge". When inserted over the crank flange and into the RMS opening of the cases, if this tool touched the RMS bore edge or showed the case bore and/or crank flange was off visually center, no retrofit of bolts or a new seal was going to save the day and the engine had to be replaced. So it is more than just the bolts, but as Porsche also began using the longer bolts in regular production engines, most of the later engine's already carry them, and replacing them with new versions of the same bolt really does not accomplish anything. The IMS flange would get new bolts, however.
5. Your current RMS (part number 997.101.212.00) is the PTFE unit, which was introduced in 2005, so yours must have been changed at least once. The IMS "part number" you have noted is for the rear flange only, not the IMS itself. But I would ask one question concerning the IMS in the engine: What size socket fits on the center bolt nut in the flange?

[Domiac]

1. But I would ask one question concerning the IMS in the engine: What size socket fits on the center bolt nut in the flange?

Flange center bolt's nut is 13mm.

(I suspect it has been touched because the other three bolts on the flange are "indented" 6 point torx, not traditional hex bolts like some of the other bolts on my images.)

Once again, much appreciated, excellent answer JFP, :notworthy:

Edited March 28, 2014 by Domiac

[JFP in PA]

1. But I would ask one question concerning the IMS in the engine: What size socket fits on the center bolt nut in the flange?

Flange center bolt's nut is 13mm.

(I suspect it has been touched because the other three bolts on the flange are "indented" 6 point torx, not traditional hex bolts like some of the other bolts on my images.)

Once again, much appreciated, excellent answer JFP, :notworthy:

OK, with a 13MM center bolt nut you still have a removable IMS bearing (the non serviceable unit is the only one using a 22MM nut).

The flange bolts are the correct single use microencapsulated units, you should have new ones with the IMS kit.