Engine mount or clutch

[DannyLee]

Hello chaps,

I wonder if you can help me diagnose a problem with my 1999 996, C4 cab 77k miles (new clutch/engine at 12k miles).

 

What has come on over the last couple of weeks is...

 

Quite severe juddering when moving away in 1st and reverse.

Worse after a 15min drive.

Worse at low-rev pull away/reverse than higher revs.

No hint of clutch slipping when fully engaged and driving hard.

 

Some vibration/wobble *which is new) after a drive when at standstill - which makes me think engine mounts.

 

I have the car in for a Porsche 'health-check' in a week or so, but I don't want them to replace the clutch £1000 (probably plus extras, e.g. flywheel, RMS, etc) if it could be the mounts.

 

I'll have a go at taking the mounts out at the weekend.

 

Is there a transmission mount - and is that a possibility too?

 

What should I look for, will it be obvious?

 

Do the symptoms sound consistent with clutch or mounts, both, or something else.

 

Any help would be appreciated.

 

Thanks in advance,

Danny

 

[JFP in PA]

Hello chaps,

I wonder if you can help me diagnose a problem with my 1999 996, C4 cab 77k miles (new clutch/engine at 12k miles).

 

What has come on over the last couple of weeks is...

 

Quite severe juddering when moving away in 1st and reverse.

Worse after a 15min drive.

Worse at low-rev pull away/reverse than higher revs.

No hint of clutch slipping when fully engaged and driving hard.

 

Some vibration/wobble *which is new) after a drive when at standstill - which makes me think engine mounts.

 

I have the car in for a Porsche 'health-check' in a week or so, but I don't want them to replace the clutch £1000 (probably plus extras, e.g. flywheel, RMS, etc) if it could be the mounts.

 

I'll have a go at taking the mounts out at the weekend.

 

Is there a transmission mount - and is that a possibility too?

 

What should I look for, will it be obvious?

 

Do the symptoms sound consistent with clutch or mounts, both, or something else.

 

Any help would be appreciated.

 

Thanks in advance,

Danny

 

Your problem sounds more like a mount issue rather than a clutch problem.  In order to check out the mounts, you are going to need to access and inspect them, looking for tears or deformation in the rubber isolation sections.  Most commonly, they tear with age, causing symptoms like you are describing.   Both the engine and transmission have mounts, and it would be a good idea to have a reference source on hand while doing the inspection, such as the Bentley 996 manual, which gives you both photos and diagrams to work from as well as "how to" information on removing and replacing any of the mounts.

[DannyLee]

Well I had a go this morning. I think the nut under the car is 18mm and needs to be long reach as the bolt sticks through quite a bit.

Actually I don't have such a socket but managed to put something together, however I couldn't budge it - too tight. Have sprayed some WD. Might try again later with the right tools. Thanks for the reply, I'll let you know the result.

[DannyLee]

An update:

 

My Porsche dealer has inspected the mountings (without removing them) and they think they are OK. If they had to remove them they would replace them, they say.

They think the problem is with the clutch, so have removed the gearbox. In there they report that the clutch is worn and also the flywheel.

This work comes in at a little under £2k.

[JFP in PA]

An update:

 

My Porsche dealer has inspected the mountings (without removing them) and they think they are OK. If they had to remove them they would replace them, they say.

They think the problem is with the clutch, so have removed the gearbox. In there they report that the clutch is worn and also the flywheel.

This work comes in at a little under £2k.

 

 

Good time to consider updating your RMS and IMS bearing while it is already apart.

[DannyLee]

Well I wondered about that.

It's all back together now and drives very nicely - better that before - gear selection much easier and pull away smoother - as one might expect I suppose.

 

The car had a new engine and clutch under warranty at 16k miles due to the RMS, and it wasn't leaking before it went in.. 77k now.