IMS bearing replacement on 996 ?
Discussion
Hello.
I have no doubt this question has been asked before, so please forgive if you have dealt with this before.
I have 2004 996 convertible which has 53k miles. I have heard various stories ( mostly horror) about an ims bearing that might needs doing
My question is do I need to have this done or not and if so how much would it cost. Thanks
I have no doubt this question has been asked before, so please forgive if you have dealt with this before.
I have 2004 996 convertible which has 53k miles. I have heard various stories ( mostly horror) about an ims bearing that might needs doing
My question is do I need to have this done or not and if so how much would it cost. Thanks
..........there are about a thousand threads on this, but as I have plenty of time on my hands... 
I don't really know in detail about the 996 3.6 engine, but the various issues they have either crop-up, or they don't. IMS bearing is only one of these issues.
Having the work done 'just in case' vs waiting to see if anything goes 'bang' is a tricky choice.
Are you keeping the car forever? Drive it and save 100 GBP a month towards an engine rebuild that might never be needed.
If not, and such things play on your mind, sell it. But I'm not sure how much they are worth, or what you'd replace it with that has a better statistical chance of being trouble-free.
Do you need four seats? If not, sell it and buy a 986 2.7, and keep the remaining money as a pot for any engine rebuilds on the Boxster.
Buy a TVR
I don't really know in detail about the 996 3.6 engine, but the various issues they have either crop-up, or they don't. IMS bearing is only one of these issues.
Having the work done 'just in case' vs waiting to see if anything goes 'bang' is a tricky choice.
Are you keeping the car forever? Drive it and save 100 GBP a month towards an engine rebuild that might never be needed.
If not, and such things play on your mind, sell it. But I'm not sure how much they are worth, or what you'd replace it with that has a better statistical chance of being trouble-free.
Do you need four seats? If not, sell it and buy a 986 2.7, and keep the remaining money as a pot for any engine rebuilds on the Boxster.
Buy a TVR
As I have a moment.
You have a car with the single-row IMS bearing, which is the weakest one of the lot. This carries the highest risk of failure, and the subsequent expensive engine rebuild. There are numerous articles on the subject, but personally I'd get it replaced with the 'LN' ceramic bearing kit. I'd also use the opportunity to have a clutch replacement done as the clutch & flywheel are coming out anyway. This is what I did with mine when I bought it - although mine needed a clutch anyway.
Of course, replacing the IMS bearing will do nothing to stop it bore-scoring, so you might want to consider a lower temperature thermostat, and increasing the frequency of oil changes (not that this ensures it won't bore score, but does seem to reduce the likelihood).
You have a car with the single-row IMS bearing, which is the weakest one of the lot. This carries the highest risk of failure, and the subsequent expensive engine rebuild. There are numerous articles on the subject, but personally I'd get it replaced with the 'LN' ceramic bearing kit. I'd also use the opportunity to have a clutch replacement done as the clutch & flywheel are coming out anyway. This is what I did with mine when I bought it - although mine needed a clutch anyway.
Of course, replacing the IMS bearing will do nothing to stop it bore-scoring, so you might want to consider a lower temperature thermostat, and increasing the frequency of oil changes (not that this ensures it won't bore score, but does seem to reduce the likelihood).
Magnum has written a fairly comprehensive reply.
It's worth mentioning that there is another useful job that can be done while the gearbox is out and that is to replace the brake pipe that runs over the top of the gearbox.
It's an expensive job doing the IMS but for a marginally more fragile single row engine probably worth it both for the peace of mind, but also for the bump in resale value.
I would get a thorough endoscope check for bore scoring done beforehand however.
It's worth mentioning that there is another useful job that can be done while the gearbox is out and that is to replace the brake pipe that runs over the top of the gearbox.
It's an expensive job doing the IMS but for a marginally more fragile single row engine probably worth it both for the peace of mind, but also for the bump in resale value.
I would get a thorough endoscope check for bore scoring done beforehand however.
Mine went in for a clutch (as heavy) and oil leak fix but GCR found slight play in the IMS when they were fixing the oil leak and I got the call seeking approval to change while they were in there. I’d discussed before hand about IMS replacement and they’d recommended, based on low numbers of failures they see, to leave it. Changing in situ comes with risks as well and in my case precautionary.
Oh and they fitted a new clutch helper spring on the pedal.
Oh and they fitted a new clutch helper spring on the pedal.
There's about a 10% chance of the IMS failing at some point, according to the US lawsuit. If it breaks, you're looking at a bill of between 10-15k.
It'll cost around £1500 to replace the clutch and IMS.
just depends on how you view risk and if the worry will ruin the enjoyment of the car for you.
However, even if the IMS holds, the engine is liable to bore score and wear its main bearings eventually, but you'd probably looking at another 60k miles for that to be an issue
It'll cost around £1500 to replace the clutch and IMS.
just depends on how you view risk and if the worry will ruin the enjoyment of the car for you.
However, even if the IMS holds, the engine is liable to bore score and wear its main bearings eventually, but you'd probably looking at another 60k miles for that to be an issue
I had an '02 C2. Regularly driven with about 75k miles on it. It needed a new clutch so I asked the mechanic (ex Porsche, lots of Porsche classic experience) to check the bearing. He detected very limited movement in the bearing so I replaced it as the clutch was already out and it was having a few other things done. Most cars will make 100k miles on the original bearing so I'd only bother doing it if you needed a new clutch. I think he used the LN replacement. There's lots of BS floating around about these bearings, the risk and their replacements - my best advice is to get a mechanic you trust and listen to his advice. Plenty of advice on 911UK too.
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