Light knocking on cold start 95 525i

[Russell]

Noticed a light knocking this morning as my wife pulled out of the driveway in my 95 525i. It was the first start of the day (about 45 degrees). Did not really seem to change with change in engine speed.

When she returned no knock after engine warmed up. Not sure what is causing this. Oil and filter changed 600 miles ago with oil level proper. Belts and pullies, water pump and motor mounts all within 12 months. No sure there is any issue.

TIA

[Kalevera]

Could be VaNOS rattle -- still 117k miles on the car?

It would be more like a tick, from the top front of the motor.

best, whit

[632 Regal]

what oil are you using?

[Interceptor]

what oil are you using?
Whatever he's using, I bet he'll end up using Mobil 1 0W40 after you're done with him :)

[liquidtiger720]

I still get the rattle with ow40 =p.

[Russell]

Currenty 600 miles into an Auto-rx rinse phase. Auto-rx is a gentle metal cleaner not a harsh flush. See past posts for discussion or check BOBISTHE OILGUY forum. You must use conventional (not synthetic oil) oil for 2,000 miles then use what you want. I am using Havoline 10w40. In the past I used Mobil 1 0w40 and Mobil 1 truck and suv 5w40. When this process is over, I will go back to Mobil 1.

Possible that this process is causing some strange noises. From BOBISTHE OILGUY I understand it can cause some unusual behavior as it cleans..

[632 Regal]

has the noise just started after you started doing this flush thing? whats the oil look like?

[Russell]

still 117,000 miles or so

[Russell]

The knock is new today as near as I can tell. The flush thing started about 2,100 miles ago. The rinse oil looks great. I do a blotter test on it every 2 weeks to see how the color changes. It is it slowly getting darker. About the same as Mobil 1 does.



has the noise just started after you started doing this flush thing? whats the oil look like?

[peterllo]

Bentley Guide says a light knock that goes away after a couple of minutes is normal with outside colder temps. As oil pressure builds and engine warms, it should go away.

[632 Regal]

man I hope the oil hasnt broken down to the point of wearing out the bearings... I experienced this as a kid with engine flush, only happened one time....never did any additives since.

[Russell]

Car seems to run perfectly. Oil/filter only has 600 miles on it. I checked for noise this morning when temperatures were about 37 degrees. I did not hear any knock or rattle. Power and gas mileage seems quite good. No oil consumption and no smoke. Thanks for the thought

[Russell]

thanks