e90330

Hi all,
I bought the car 6 months ago, did a lot of work to it as the engine was leaking oil like there was no tomorrow. Electrical gremlins which caused the batter to go flat over a period of few hours etc. Slowly solving all the issues. Next on the list is a rattle I get from under the hood. It's repetitive, does not go away when I go up to 100 rpm. It does go away when I switch on the aircon. When I switch it off again, it takes a few minutes before it comes back. I'm thinking in the direction of aircon compressor, compressor clutch, belt tensioner, pulleys, but I can't make out what it is. I attached a video where you can hear the noise. Any help would be appreciated.
Also, is it normal that switching on the aircon, raises the idle from around 500rpm to around 750rpm?

Thans a lot!

Video

seanjordan20

That sounds like lifters. What type of oil did you put in. I know my friend had a sound similar and when I put in 0w40 it mostly went away.

e90330

I'll check on my way home and report back. Is 0w40 the correct oil to to use with N62?

e90330

Shouldn't lifters then make a continous rattling noise? This rattle is going away, then coming back, sometimes a bit louder, then quieter, but always there. Unless I switch on the aircon, then it goes away.

e90330

Also, you can hear the rattle better towards the end of the video. I'm not referring to the constant knocking btw. That will be something to fix as a next step

seanjordan20

Now I'm hearing what you're taking about. Something is in a slow rotation rattling every few seconds. You can't tell if it is coming from the bottom or the top?

seanjordan20

With the oil the dealer puts 5w30. To me the engine sounds better with the 0w40 (less ticking). Have been using it for over 7 years in both my BMWs.

turbineguy

Hi,
I have had my 545i for about 5 years now and seam to be constantly tracking down odd rattles/clunks. I had 2 issues with rhythmic on/off rattles: one was the water pump bearing starting to go bad (sounds just like your noise and easy to check) and the second was with the vanos system (it was a slower, deeper, rattle and was fixed while playing with code reader (launch x491 pro mini) when I did a re-learn on the vanos (I can't remember the exact name) lift or actuator). To me, your on/off rattle sounds like the water pump. Remove the belt and check for radial play in the pump pulley. Let us know the results!

Cheers.

e90330

Car will go to a shop in a few weeks, so I hope they’ll find the issue and that it will not break the bank :-/... I’ll update here if there is some news