Trying to diagnose this rattle. 2009 R56S with about 120,000 kms on it.

https://youtube.com/shorts/k-G9WtQKXHI?feature=share


Recently replaced the VANOS solenoid, thermostat and did an oil change. Replacing valve seals soon (light smoking, want to get ahead of it) but I feel like none of that would be the cause.

I think it goes away once the engine warms up. Could it be something as silly as oil that’s too light? I put some Mobil 0W40, should I go thicker on the low end?

 

Best quick and dirty guess is that it is the vacuum pump coupling rattling - likely due to the vac pump getting tired and starting to stick a bit. Does not sound all that bad.

Did you check the video to make sure the recorded sound is fairly accurate?

If it gets much worse replace the pump.

If it turns out to be the pump, reduce your oil change intervals - dirty oil fouls the pump.

 

Cool. Thank you for this. The sound should be fairly accurate, it's a sort of clacking / tapping sound that changes rhythm, I wasn't sure if it was something in the cylinder block itself or not. Vacuum pump would be a good thing to replace, it's still original (75K miles on the car), so I wonder if it's slowly starting to go. What should I pay attention to to make sure it doesn't explode and take the engine with it?

 

Least risky path forward is to replace it. At 75K miles 10+ years, you have gotten your money out of it....

The Pierburg aftermarket pump is good and a very easy DIY task.

 

You're probably right. Ordered, let's see if that solves the sound After doing the thermostat and the water pipe, I feel I can take on the world... lol

 

Curious if the new vacuum pump fixed your problem @jbourne . My daughter's car has a similar sound, though not as loud. Thanks!

 

It helped a LOT. Weirdly, I don't think it completely removed the sound, but I'd say it's 90% gone (so maybe that's the "normal" sound that it should be emitting). It was a really, really easy DIY so I'd strongly recommend you to just swap it if it's old - literally the most difficult part was aligning it with the camshaft (and that just meant taking it out and slowly rotating the groove on it until it matched up). Very easy.

 

Thanks for the update and encouragement... Definitely gonna check it out!

 

All thanks to @thefarside - was his idea!