Porsche Enthusiasts Club Forum

I get a lot of stick for buying a 911 with a 'dodgy' engine.

So, just how bad are the IMS and/or bore-scoring issues...?

Bad enough if they occur, for sure, but what are the chances? How much of it is 'hype'...?

What are the symptoms...? IMS bearing failure...? Bore scoring...?

Is there anything I could/should be doing to stave off the issues? More regular oil changes...? Different oil...? Cooling...?

Are there any known mods that will/might help? (Does anyone really understand the cause...? If so, why haven't Porsche fixed it? Or have they...?)

My warranty period is coming to an end in a couple of months. It'll be £2000+ to renew it for two years, which is about half(?) the price of an engine rebuild; so unless the chance of expensive failure is about 50% (!), it's probably not worth it...? Or is it..?

I mean, it's been OK so far, hasn't it...?

What do you guys think?

I think the leading researcher in the UK has been Hartech? I personally haven't even looked into it but it wouldn't put me off buying a car with that engine in it. I think Hatech offer a lower temp' thermostat that might help? The truth is I had a brand new Pugeot 407 that they couldn't fix and my dad had a VW Bora that they finally gave him another brand new car as a replacement because of issues. It's not just Porsche when it comes to bad luck with cars is what I'm trying to say.

The internet doesn't help. One person posts and everyone now knows someone it's happened to and now my whole family know of someone it's happened to. At least you haven't paid out hundreds of thousands for it to go on fire, or be sitting in the garage in case it bursts into flames.......

I'd drive it like you stole and enjoy it for what it is.

I run heavier oil than Porsche use to A. Help protect the IMS & also B. reduce the chance of bore scoring.

General consensus is that the oil that is typically used 5W/30 or 5W/40 is too light to protect the IMS once it ages & that bore scoring is oil breakdown. Mine is now on 5w/50 & I think Hartech recommend 5W/60 & require it for their rebuilds to keep the warranty.

IMS failure is catastrophic & happens very quickly once the bearing breaks up. Various fixes available, although interesting that Hartech don't recommend IMS replacement by the extraction in-situ method. Difficult if not impossible to diagnose beforehand.

Bore scoring normally shows in excess oil consumption & can be investigated using a bore scope, around an hours work on a ramp.

I have just had the IMS ugrade done on my 996. I have only just got the car, but it had an oil leak which was the RMS, the dealer replaced the RMS and since the engine was out I took the opportunity to get it done.

I have read on the web aboyt failures, but no idea how bad it really is, and C4's and tiptronics are supposedly lower risk, but I took the view that I want to keep the car for a few years so see the expediture as a warranty - sometimes you can get a warranty for your car and need to claim other times you don't claim at all.

So I purchased the car expecting to spend money on it and for piece of mind I thought it was better to invest in my engine and not a warranty - this may be the wrong choice in the long run but I am happy.

Fit a low temperature thermostat, magnetic sump plug, regular (at least once per year) oil changes - use Millers Nanodrive CFS 10w50 NT engine oil.

Enjoy!

Thanks for the replies, guys.


Oil consumption in minimal, so OK on that score, thankfully...!

Am I right in thinking that the IMS bearing issue was fixed on post 2005 cars...?