Top engine noise? M3 E36

[shepp80]

Hi, I have a E36 M3, the vanos unit has been replaced on it around 15k ago. Engine runs fine both hot and cold, pulls like a train still. But on idle there is a rattling sound. If you rev from around 2000rpm and let go of throttle its mostly heard. Not when reving excesively. Oh and when engine is cold you cant hear it either, just when engine gets to temperture.

The sound is really annoying. Ive looked over the internet, on a few forums, and people have advised to change the grade of oil? I use 10/60 TWS motorsport oil from BMW at the mo, but now being told that thats best for the S54 engine? and to use 5w/40 or 10w/40????? different viscosity??

Can any one please advise me what to do????????????? Really want to quiet this noise

[M3John]

I replaced my VANOS units a while ago now as a matter-of-corse and after the new ones were fitted they sounded exactly the same (maybe marginally quieter. The easiest way to tell if you have a problem is to go out for a drive and whilst in gear - 4th shhould do it - floor it. At around 2.5k rpm you should notice a definate kick in acceleration.

Sounds to me that they are perfectly fine, unless that are sounding like an empty machine gun. If so you might be heading for problems.

Edited by M3John on Tuesday 7th April 12:58

[duff]

Are you sure it's coming from the engine itself? Mine made a rattling noise at around 1500-2000 rpm and I'm pretty sure it was down to the exhaust manifold flexi joint leaking although it was pretty quiet at idle.

[mat205125]

duff said:

Are you sure it's coming from the engine itself?

That's the first thing to check!

Get a mate to sit in an do the blipping of the throttle to make the engine generate the noise in question, and listen all around the engine bay - sticking you ear to the handle end of a long screwdriver held on different parts of the engine isn't just for people trying to work out why their A-series austin isn't playing ball.

[andye30m3]

My engine made a slight tapping noise at tick over and just over for a month or so before suddenly getting very bad on the M25 and spinning a shell. It sounded like it was coming from the top end / middle and towards the back of the engine.

Thats obviously the worsed case but worth getting it looked at I wish I had.