“I love my Aston”, I was wont to say, “but for sheer reliability and general go-down-to Tesco’s-in-it ease of driving give me the 911”. I was wont to say that but no longer. I just had a rather salutary experience with my treasured 996 model Porsche which has created a new British and Empire record for most expensive ever DMcA garage experience.
For other current or potential 996 or 997 owners, here is some information that may save you some heartache. Or it may not.
It turns out that there are two huge ‘blow the engine up’ problems that lurk on ALL Porsche 911s and Boxters from 1997 to around 2008. The first is the cylinder sleeve liners – which can disintegrate, causing the engine to seize. I knew about these and thought the risk was manageable. The second is a potential killer as it is unpredictable and can occur quite suddenly. It is described here in regard to Boxters, but this applies to all the flat 6 boxer engines of the period. The IMS runs the engine timing and is housed in a bearing of poor design which fails under fairly unpredictable circumstances. If it fully fails in the engine, it breaks apart, flying bits of metal and swarf through all the bearings, liners and heads. Your engine is f*ck*d. Mine btw had partially failed saving the liners and heads, but requiring a complete engine strip, and replacement of all the major engine bearings and seals, Hence the 4ft long bill on the left.
What remedies are there? You can buy a second user engine, but if cheap, it will have the same problem. A new engine from Porsche is £13,500, or $20KUS. To just take the engine out, strip it down, and put it back – i.e. no parts, no repair, is £3500 or $5KUS. The parts are around £1500-£2000. This plus the labour in actually fixing the problem, plus fixing other things like the exhaust (that were cheaper to do because the engine was out) led to my total massive bill. The alternative is scrapping the car.
I have no issues with my Porsche mechanics (GT One) – they are well rated and expert and I would recommend them. These phone-sized repair cost numbers are the going rate I found on phoning around.
So if you have a boxer-engined Porsche of this vintage, what should you do? GT One tell me they have seen this happen on cars with as low as 20k miles (on one 20k example the engine did blow up, and the bill was £15k for a new engine) and on all cars up to late model Gen 1 997s. So I would assume it’s going to happen. If you are about to buy one – don’t unless the IMS bearing has been replaced. If you already own one, replace the IMS bearing fast – if you catch it before it starts to disintegrate, it can be done for around £1-2k, not the £7.5K it cost me. This is possible because as long as the bearing has not failed, it can be changed without removing and stripping the engine for all models up to 2008. The process was developed by LN Engineering who have a useful video here of what a failed bearing looks like. A good description of the process, from Lakeside Engineering is here.
If I had known about this I would have had the LN bearing fitted pronto. It can actually be done by a competent home mechanic for even less – the bearing kit cost is around £700, so it’s potentially 10% of what it cost me. By the way – there are a couple of ways to tell if the bearing is failing. I could hear a definite whine, which I attributed to the cooling fans – but which has now, post repair, gone. I think it was the bearing noise. LN engineering say there is a characteristic rattle you can hear in the area close to the IMS. I wish my guys had listened when they did a service. I suggest you get your own mechanics to do a listening test in the first instance. The next test is to remove the intermediate shaft hub flange, and then the bearing can be easily checked for wear (see at 1 min 10 secs in the LN Engineering video). If worn, get it fixed and you will save yourself the price of a new Korean city car!!!!