Originally Posted by DanchoD
I have a late 2007 E93 325i auto with the N53 engine.
A few months back I noticed a slightly irritating ticking noise which becomes more prominent on acceleration. I've not had any error codes or loss of performance, so I just put up with it.
Curiosity got the better of me so I started looking into it and came across this thread. There was a recommendation for the N52 engine to rev to 2500rpm for 3 minutes while stationery. Even though I have the N53 I thought I'd give it a go.
After about 2 and a half minutes there was a noticeable change in rev noise and the ticks went away! But disappointingly they returned a day later. I thought I'd try it again this evening and once again the ticking has stopped.
What's wrong with my car? I have the extended BMW warranty (UK), is this problem likely to be covered under warranty?
I'm reluctant to pay the extortionate diagnostic fee!
This is the most informative post on the thread. A description with the TSB via BMW USA. It is for BMW USA but it should help. See what may overlap in the UK from your service adviser.
Also, this link is dated, but it includes the bleeding procedure which it seems you are doing at this time. It does not work. However, it gives a bit more information on the problem, a good read so to speak.
Also, click on my signature, this is what it sounds like. It takes you to U2B.
FYI the N53 is new to me, Wiki I found interesting.