E46 M3 - head gasket gone?
 

Morning all

Was just driving around in town for work and my M3 just developed an 'issue'. I've got bad vibrations and hesitation from the engine, along with increased noise. My car has been running *slightly* warmer than usual recently and my main indy thinks the symptoms fit a head gasket failure.

Have you guys got any thoughts? And any idea of pricing? My indy has quoted about £1100 for the replacement, including a minor head skim.


Thanks all!

Not sure about the running hotter bit, but a common cause of a sudden onset of lumpy running is the coil packs.

Have you had any fault codes read to suggest it might be HG ?

When mine went it was noticibly lumpy at tick over and you could hear 'pulsing' from the exhaust. At motorway speeds under acceleration there was a distinctive 'tinkling' noise apparent from sat inside the car.

BMW charged almost £2.5k under warranty although they did replace the sensors in the exhaust system whilst they were at it. It would have been just over £2k without sensors but including the head skim.

Mine revealed no fault codes directly related to the issue - only showing a throttle flap potentiometer issue lol!

No code reads yet, that should happen later tonight. I changed the plugs about 2k miles ago (Inspection 1) - tempted to remove/reseat plugs and coil packs as it can't do any harm.

Fixed. A code read revealed a misfire on cylinder 4. Swapped Cyl 1 & 4 coils and it moved to Cyl 1. New coil pack and done!

Interestingly, the coil that died was a Bremi one, yet all others are Bosch. Tut tut whoever replaced that...

Its probably the only one that wasn't changed,as the Bremi ones were original;)

Nice one Jimbo, a cheap escape there :thumbs:

Now sell it, before the HG does go! :hahaha:

i had this recently. started with a misfire, hunting on idle, exhaust emmisions light came on, indy replaced a coil, better but not fully fixed. did a compression test showing cylinder 4 down, 5 even more so, different specialist did head gasket for me. was fooked between 4-5-6.

hope not mate but see if it stays better., if not get compression test done.

what sort of money are coil packs these days ? :shock:

:smt023 Always do compression test with any kind of misfire, even if a coil pack change does the job.