Confused by the E9x M3

[DavidJG]

Long story short - my company car goes back in a few months time, and due to the truly cruddy car list that we have now, I'm taking cash instead. The good news is that when I take cash there are no restrictions at all on what I can buy. Some of our guys even take the cash and don't have a car at all.

Seriously thinking about the E90 M3 as a good option. But there's one question that I can't quite get a simple answer to: some say that this is one of the most reliable cars BMW have ever made. Others say that this engine is a time-bomb that will spin rod bearings sooner or later, and need a replacement engine at very high cost. As I tend to keep my cars for a long time, this is a worry.

So, what's the truth about this car, ultra reliable and brilliant, or high risk of grenading engine and subsequent huge invoice for a replacement??

[DavidJG]

I guess my worry is that from what I can see, rod bearings fail without any real warning, and there's no 'obvious' time / mileage. As an example, the upgraded IMS for Porsche M96 engines has a recommend life of 40,000 miles. I seem to hear of S65s with spun bearings at < 30k, and others that go 80k + without any problems. This could be down to driving style though - I never work an engine hard until I know it's properly warmed up, but previous owners may not have been so mechanically sympathetic.

[DavidJG]

Patrick Bateman said:

I suspect, as ever with forums, the rod bearings 'issue' is greatly exaggerated.

I suspect it probably is. It also seems that a lot of reported problems are in the USA, with modified engines. I've got a local Indy, so might look at cost for a 'preventative maintenance' replacement anyway though.

[DavidJG]

jcolley said:

Of the twelve S85s and 3 S65s I've pulled apart, not one had over 70k miles and the bearings were highly worn, over half of those through the Babbitt. Only two of those were modified and one only with a tune.

There's a chap on M5board (GJS) who lives somewhere in the UK and has experienced similar with several S85/S65 rebuilds. Another from Germany (Duschanio) has opened up well over 30.

There's a well respected fellow in Luton (Raikku with Evolve) who will share the same perspective and has rebuilt numerous S65/S85s and is adamant the bearings should be replaced preventively.

As a matter of interest, were any of those engines showing signs of bearing failure before some sort of failure, or did the owners effectively have zero warning before something failed?