IMS Issues.... Which cars?

[aruck]

I've been reading the Porsche forum for a while now trying to establish which cars have expensive engine issues. I originally thought it was just the 996 and 997 but then read somewhere that this also applies to the 986 and 987? Is it all engines?

I'm interested in possibly a 987 3.4S; does this have issues? I'd really like a 997 but I think they are slightly out of my price range for now.

Does the cayman have the same problems?

Thanks

[STiG911]

The 996 and 997 series 911 as well as 987 series Boxster and Cayman (er, can't remember the 'internal' number) all use the same engine family.
This means all have the potential (note, potential) to have issues with their IMS or bore scoring. Given that you only ever really get to hear about problems on forums you could be forgiven that every car is a wallet-bomb, but if we believed everything we read, we'd never leave the house.
I'm sure that with the right knowledge, and, more importantly, confidence in the place you purchase your car, and the support you're likely to receive, you'll bag yourself a top-notch example and be far too busy grinning like a loon to worry about such things.
Good luck

[Waitforme]

The later models of the engines with the IMS have an upgraded bearing and seal.
I'd like to see figures of the failures on these upgraded engines in comparison to the early ones.

If the engines without the IMS ( the DFI ones ) are in cars just slightly out of your budget , if it were me I'd find a wee bit more or wait 6 months until they fall into your budget.

Or warranty the car and sleep easy.

[Ian_UK1]

aruck said:

I've been reading the Porsche forum for a while now trying to establish which cars have expensive engine issues. I originally thought it was just the 996 and 997 but then read somewhere that this also applies to the 986 and 987? Is it all engines?

I'm interested in possibly a 987 3.4S; does this have issues? I'd really like a 997 but I think they are slightly out of my price range for now.

Does the cayman have the same problems?

Thanks

As I understand it, the IMS bearing failure 'issue' can affect any water-cooled car (Boxster/Cayman/911) built from 1998 to 2009. From Aug 2009, the new DFI engines were introduced that were a clean-sheet design and don't have an intermediate shaft as part of their design.

The reasons for the bearing failure have been documented at great length on here - particularly by Baz Hart (Hartech). The search engine is your friend on this one. In short, a sealed, ball race bearing is used to support the flywheel end of the intermediate shaft. Over time, the grease in the bearing can dry-out - often aided by excessive running temperatures as some of the bearings are a very tight fit in the casing due to production tolerances. As the bearing is sealed, oil from the engine can't normally enter the housing (although it sometimes does, with the effect that the bearings go on 'forever' - read elsewhere for full explanations) and the bearing eventually breaks-up leading to catastrophic failure.

It appears that the main reason for the failures - the lack of lubrication as the bearing ages - has never been correctly addressed by Porsche. What Porsche has done is re-spec the bearing several times - single and double row bearings have been used, in several different load ratings. As all of the specified bearings have been nominally strong enough to carry the loads they have to bear (some many times the nominally required rating) but all have been of the same sealed design, the failure rates don't seem to be much different, irrespective of the bearing's spec / manufacture date of the engine.

A small number of engineering shops, here and in the USA (including Hartech) have managed to redesign the bearing so it receives plenty of engine oil to both lubricate and cool it - this seems to have effected a cure. Such modified engines (that often have other modifications to the cooling system and cylinder bores) are greatly prized and seem to be more-or-less bullet-proof.

Bear in mind that the number of failures (despite all the discussions on here and other Porsche forums) appears to only be a very small percentage of the total number of engines out there. The old adage that bad news gets discussed ad infinitum on forums, whilst good news never gets a mention, is probably very true where these failures are concerned.

From personal experience, I've had a 3.4 996, a 3.6 996 and a 3.8 997S. All of these had the M96/7 engines, were well looked-after (oil every 6-8000 miles, regularly serviced etc.). Despite driving the cars very hard on occasions and racking-up some substantial mileages - well over 130,000 over the 3 cars - I never saw an engine failure.

HTH

Ian

[Wills2]

Ian_UK1 said:

From Aug 2009, the new DFI engines were introduced that were a clean-sheet design and don't have an intermediate shaft as part of their design.

Sorry to be a pedant but the DFI gen2 was launched summer 08 not 09.

[Ian_UK1]

Wills2 said:

Sorry to be a pedant but the DFI gen2 was launched summer 08 not 09.

Absolutely right - my bad.

[aruck]

I sometimes think I should stop reading the doom & gloom about IMS issues and buy the 997 that I want. I can't help thinking that if a £5k bill came along for a rebuilt engine I would very much regret saying that. I don't like the idea of £100 a month warranty either. Rock, Hard Place!

[Slippydiff]

Ian_UK1 said:

Absolutely right - my bad mistake

[Chrisp5782]

Wills2 said:

Ian_UK1 said:

From Aug 2009, the new DFI engines were introduced that were a clean-sheet design and don't have an intermediate shaft as part of their design.

Sorry to be a pedant but the DFI gen2 was launched summer 08 not 09.

Only in the S versions. The "base" models didn't get DFI until later.

[Birdster]

So what happens to all the sub 10K Boxsters and 911's. (986/987). They don't get scrapped do they?

Actually I'm guessing that they get sold for breaking for about 1K. Which eventually will make them quite rare.

[stuckmojo]

aruck said:

I sometimes think I should stop reading the doom & gloom about IMS issues and buy the 997 that I want. I can't help thinking that if a £5k bill came along for a rebuilt engine I would very much regret saying that. I don't like the idea of £100 a month warranty either. Rock, Hard Place!

No need to spend £5k. Get an independent to replace the bearing with a new OEM one without seal, frequent oil changes, lower temp thermostat and you'll be fine.

[kingston12]

Birdster said:

So what happens to all the sub 10K Boxsters and 911's. (986/987). They don't get scrapped do they?

Actually I'm guessing that they get sold for breaking for about 1K. Which eventually will make them quite rare.

It might take a while before they get rare. In reality, this issue only affects a tiny proportion of the total volume of these cars. The risk is a consideration when buying one, but for me it would be more of a problem if I was spending bigger money on a later car.

The 986/996 price are absolute bargain basement right now and I think that the prices take account both of the ubiquity of these models and the higher risk of a big bill than, say, a Z4 or S2000.

[Chrisp5782]

I think, and I've said before, we need to apply a bit of common sense to the IMS issue.

I wouldn't for a second fly in the face of evidence and say there isn't an issue but.....we need to look at the number of 986 /987 /997 cars out there that have had failures and compare that to the number out there that haven't, the statistics, I'm sure would fall on the side of the latter!

If the problems were as wide spread as some forum posters would have you believe the bloody things would pop as soon as you opened the garage door!

I guess it's a little like winning the lottery - it could happen but the chances are slim, really slim and people shouldn't be put off buying the cars in the first place.

According to a couple of the American forums it's every third car that craters it's engine, utter bks, it may have something to do with the fact that the yanks strap a turbo on everything without upgrading any other engine internals?

As a yard stick - I'd invite any 986 / 987 /997 owner that has had an IMS failure to add to this thread, I bet it's not as many as you might think............;)

[anonymous-user]

Ian_UK1 said:

As I understand it, the IMS bearing failure 'issue' can affect any water-cooled car (Boxster/Cayman/911) built from 1998 to 2009. From Aug 2009, the new DFI engines were introduced that were a clean-sheet design and don't have an intermediate shaft as part of their design.

I thought the water cooled dry sump Mezger engines produced in that period were not susceptible to IMS issues - that exempts GTx and Turbo cars.

[Magic919]

There's already a stickied thread where a poll indicated numbers afflicted with IMS failure. It's just PH of course and some owners only sign up here once their engine has gone bang.

[Chrisp5782]

Greg66 said:

Ian_UK1 said:

As I understand it, the IMS bearing failure 'issue' can affect any water-cooled car (Boxster/Cayman/911) built from 1998 to 2009. From Aug 2009, the new DFI engines were introduced that were a clean-sheet design and don't have an intermediate shaft as part of their design.

I thought the water cooled dry sump Mezger engines produced in that period were not susceptible to IMS issues - that exempts GTx and Turbo cars.

You're quite right, Turbo and GT cars use a different block and internals and are free from such issues.

[kingston12]

anonymous said:

[redacted]

Yes, the supply makes a massive difference. S2000s are cheaper than Boxsters despite having the bulletproof Honda engine. Having said that an early S2000 was a £20k car originally where as Boxster of the same vintage would have been at least twice that so you'd expect it to be at least a bit higher now.

It will be interesting to see what happens to the early Boxster prices as they do move into 'classic' territory. Decent 3.2S 986s seem to be available a lot cheaper than decent 968s and 944 Turbos now, but I wonder how far they will go.

[Moosh]

The 996 GT2, GT3 and Turbo do not suffer IMS issues as they have a different engine block.

[petop]

Under its previous owner, my 996 C4S suffered an IMS failure which resulted in him getting Porsche to fit a new engine this Feb for over £15k all in. This happened at 52k miles.
Im not worried, i have a Porsche Warranty with it and im more concerned in running out of fuel due to the silly way C4S's dont register you putting in fuel when i drops too far,until it hits around the half way point.
Yes IMS failure can happen but either worry about it and ruin the experience or just drive. By all means look into Warranties, Hartech options and LN Engineering solutions but there are other cars around with problems like RS4 suspension, BMW valves etc etc.

[Dan911]

I understand, from 2005 (2006MY) the IMS was updated.

From what I read (flame suit on) the IMS was at its worse on the 3.4 996.1, but this engine did not suffer the scored bores as much as the 3.6 996.2. So a 3.4 996.1 with a updated IMS maybe more reliable than a 3.6 996.2? (flame suit off)