S63TU failures - M5, M6 & M6 GC

S63TU failures - M5, M6 & M6 GC

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Albigularis

Original Poster:

42 posts

87 months

Friday 28th October 2022
quotequote all
So, currently in the market for another car to replace my M140i. Considering one of the above cars, as they all seem absolutely perfect for me on paper, however the amount of failures I'm seeing is a huge concern. I've ran various 'unreliable' performance cars, N54 etc, but I can't really deal with spontaneous engine failure. I absolutely adore these cars beyond belief, but I'm not sure I could cope with the constant "will it randomly die" anxiety?

There seems to be a few issues related to oil starvation from the oil pump on early cars - I believe many failures are being attributed to this though, which aren't actually this problem.

Rod bearings. This seems to be the crux of most seizures from what I've read. I've been over almost every forum and many annoying youtubers videos to look at failures, and rod bearings seem to be the cause most times. Failures from these on the S65/85 seem much less common, despite them having more of a reputation for needing replaced.

Bending rods. Quite a few of these engines which have been rebuilt have been found to have bent conrods. Even more concering this that so many of these engines have just been running on standard power. Tuning these and avoiding bent rods seems impossible? This is a big issue for me with an engine which is so easy to get north of 700bhp. Tuning up an F80 with stock turbos will be almost neck and neck in a rolling race, and no issues with engine death.

Are my fears overblown? Is buying one as Approved Used the only way to sleep soundly? I had a look at the extended warranty if I were to buy one from a normal dealership. The quote was something like £478/month. Which is about the same as the finance on the car!