15w-50 Mobil 1 seems to have solved my valve chatter

[Dick Schneiders]

One of my 1991 525i's with the M50 engine has had a very bad valve noise for several months. It would be quite loud when the engine was first started, which would go away after a minute or so. The bigger annoyance was that the valve chatter would really get bad after the car had been driven for 15 minutes or so on the highway. Then the noise would be nearly constant and would be very loud whenever the engine revs were higher than a normal cruising speed. I had been using 10w-30 Mobil 1 in this car for a couple of years.

I changed the oil and filter a couple of days ago and decided to go to a heavier weight oil, 15w-50 Mobil 1. I took the car out on the highway for a short drive and the ticking was almost non-existant. Today I just got back from a several hundred mile drive and the noise was even less noticeable. I could just barely hear it after the drive. In the past, after such a drive, the noise would be so loud when driving in the city that it sounded like a diesel truck. Also, there is no hint of the noise when the engine is first started.

I really don't know what this means, or why it improved, but hopefully the valve noise will stay at the level it is now, or even get better. It is still a tiny bit noiser than my other 1991 525i, but very tolerable.

Dick Schneiders

[molesz]

I have the same problem with my '91 520i M50.
Had a try with 0W40 synthetic, the ticking just went away faster at cold start, added an STP "thickhoneylikeadditive" and nothing changed, done an engine flush and put in a half-synthetic 10W40 ... nothing new. Actually the ticking comes from the hydraulic lifters. I do seriously consider a 24 hydro lifter change operation (costs an arm and a leg).