[alankeith]

I had a problem with ticking a month into ownership of my BMW. So I took it back to the garage who sold me it. It was being fixed under warranty.

The garage mechanic had done an oil change before I picked the car up, but the mechanic had got a new job by the time i went back with this problem.

We reckoned that the mechanic had put in part synthetic / mineral oil instead of fully synthetic, and also that the oil had been contaminated.

The cheapest option for the garage owner was an oil change to fully synthetic, and I reluctantly agreed to try it. (Remember this was under warranty, so the garage owner was paying).

I was sceptical but pleasantly surprise. When the oil had run through the engine after about 1000miles, it did work!!!

Change your oil and filter to fully synthetic.