Timing chain rattle???

[Blake23]

Hey my m50 vanos engine has a rattle that occurs between 1700-2200ishrpm.
I think it may be my timing chain but not 100%.
Is there an easy way to tell if it’s the timing chain, vanos or something else?

It also has a flat spot around 2000rpm aswell. Not sure if this has anything to do with it..

Thanks
Blake

[ZekeTheSneak]

Do you have the old style tensioner? It's the big 22mm bolt looking thing on the cylinder head. Old style has a spring where as the upgraded is hydraulic. Could be causing it. YouTube has a ton of videos in the vanos rattle. That might be your best best besides taking it to BMW or the like.

[Blake23]

Not sure.. I can just unbolt it and pull it out with out any special tools?

Yeh I’ve seen a few of them and it doesn’t sound like vanos but can’t be 100% sure

[ZekeTheSneak]

Yah just don't start it of course. How many miles are on it? You can take a prybar or long screw driver. Put it to your ear and parts of the engine to listen for the rattles.

[Blake23]

Ha yeh not starting it seems like it’s a given but I suppose there are some people out there... no idea on the km’s

It’s coming from the front of the engine for sure. That’s why I’ve narrowed it to timing chain or vanos

[CMBusch]

I would say it's most likely the Vanos, but I would definitely give it a listen first. Either the Vanos unit is making the noise, or the spring plate on the intake cam is causing it.

[f4tj0n]

When I bought my S50, the PO said that it had Vanos rattle. Upon removing the oilpan, I noticed that the oil pump sprocket had came loose and not fallen off, but pretty much stripped the splines.

I'm not trying to be pessimistic, but... could be that as well. Obviously start with the easier stuff.

[Blake23]

mmmm yeh..... I hope its not the oil pump nut because that will be a pain in the back side... The more i think about it and the more I research i'm starting to lean towards VANOS...

[mpowerful]

Thats common rpm for vanos rattle.

[Blake23]

Well if it is Vanos am I right to just leave it until I get some spare time to fix it or is it something I should be looking at fixing ASAP because it’ll damage things??

[CMBusch]

From what I understand, there's no danger. It's just annoying. The rattle is either caused by the vanos unit itself, or the spring plate on the intake cam for OBDI cars.