Intermediate Shaft Bolt
 

When I had my 01S in for it's 60k service, the dealer informed me that the intermediate shaft bolt was broken. I hadn't noticed any issues when driving the car. They said they can replace the shaft and it should be fine.
Just wondering if replacing the shaft will prevent the need for engine replacement or will the engine eventually need replacement?
How long could the car be driven with the bolt broken before it causes damage to the engine?

Was your transmission removed?

They had removed the tranny as it had a RMS leak. As part of their inspection, that is when they had noticed the broken bolt.

This is interesting. But first lets make sure.

The intermediate shaft has a nut on the end. The nut is on a threaded shaft. if that nut has broken off then there is usually catastrophic engine damage and oil pours out of the engine. You then replace the engine.

The intermediate shaft also a a flange on the end. This flange is bolted to the rear of the engine with 3 bolts. Those bolts are never a problem.

If it is the nut then I do not know. When you see a broken nut the engine is already toast. I would have to ask Peter Smith about this, as it is something new.

Does the dealer want to take the engine apart to replace the intermediate shaft?

They want to replace the shaft/bolt. They want to ensure the shaft will fit properly. If it doesn't work, then they said it may require engine replacement.

I spoke to a mechanic, as this was new to me. He has seen this a few times.

The nut goes on the shaft for the intermediate shaft bearing support. When the nut shears off it is disaster waiting to happen. The bearing for the intermediate shaft falls into the engine and you have engine damage. That is when oil pours out of the hole left by the broken nut.

He has seen just a very few cars where the nut has sheared off and the bearing has not yet moved. Porsche puts a lot of loctite somewhere (I forget where he said) and the bearing may stay in place for while. But when the engine gets hot and/or you rev it up then boom.

He said the bearing support cannot be removed and replaced from the outside of the engine. The engine has to be taken apart. At his dealership the engine is simply replaced.

That is what I was told.

Don't drive the car.

How much does your dealer want to try to fix this?

Wow! This is amazing stuff. Lets follow this all the way through.

Great information.

:)

To replace the shaft and bolt they said it would cost $1200. If the engine needs replacing it would be $6000.

This is a 2003 2.7 that I took in 2003.

The upper green line is where the nut is supposed to be. The lower green line is the broken off nut that fell down. That car was towed in because the engine had already been damaged. That engine was replaced.

This is a good engine. The yellow arrow points to where the nut should be. Right in the middle of the intermediate shaft flange.

Thanks for the pics Tool Pants,it's makes everything a lot easier to understand.

Thanks for the information. I will take a look at the engine when I'm back at the dealer.

Hopefully the shaft replacement with solve the problem.

Ask a lot of questions and take pictures, for what little good that may do you.

There is nothing you did to cause this. The M96 motor is a great design on paper. This is a weak point. Ask your dealer when Porsche switched from a double to a single bearing, and what bearing is in your motor.

Ask them why this part failed.

Good luck.

Very interesting. I know the 996 series cars still had the RMS issue, but is the IMS still an issue on the 3.4 and 3.6 motors?

Patrick

Here's an update on the problems with the IMS. There was some oil leaking from the IMS seal and it looks like when the dealer was inspecting the engine, they tried to tighten the bolt and it sheared off.
I have a new intermediate shaft being installed in the engine as there was no damage to the engine. The new shaft has 2 seals and they have improved the design of the shaft by increasing the diameter to improve it's strength. There are 2 seals on the shaft - both internal and external now.

I will post some pictures to show the differences in the shafts. Maybe a start of Porsche working to improve the design.

Cheers

Jeff, do you have any pics of the rear main seal you could point to so I can see what this rascal actually looks like?

In my nightmares, the rear main seal is about six feet tall and it spews oil out on everything around it and I drown in a pool of hot engine oil as my wife says, "I told you that car was going to be the death of you!"

Now I'm gonna have intermediate shaft failure nightmares too. :eek:

Hi,

This is nothing new, just different, incorrect, verbage. The IMS failure is mainly reserved to the '01 and later cars when Porsche redesigned the Intermediate Shaft to lessen engine vibration. When this was done, they switched to a single bearing (not the seals) over the previous two. The issue persists to this day.

What the lister is describing here is not an IMS failure, but incompetence on the part of the Dealer Mechanics who sheared off the IMS nut by overtightening it - that's something completely different. It's not an inherent failure but poor wrentching on the part of the mechanic.

The non-egas cars are essentially immune to this failure because the IMS in these cars is supported by 2 bearings which hold it on it's spin axis whereas the single bearing has been shown to allow meandering of this shaft which drives the Camshaft Chains. At high revs, this shaft become misshapened and eventually fails, breaks and shreds the Oil Seals. Ironically, usually at low revs.

In other words, Randall, nothing to lose sleep over...

Happy Motoring!... Jim'99

Whew! Glad I checked in here before I shut the laptop cover for the night (it's 11 pm now).

Who'da thunk having an OLD Boxster engine would be a good thing?

Good job Jim!

Sometimes, new and improved isn't! :D

This is very interesting indeed. So for those of us who have E-gas cars, how much should we worry about IMS failure? If my motor has already made it over 50K does that put me in any better shape (as in, I got a "good" motor since it seems a lot fail at low mileage)? Is there any evidence the 3.2 is less at risk than the 2.7 or vice versa?

Patrick