One for the experts on vacuum systems!

[ninja_zx11]

Originally Posted by mobilejo

It went into my local BMW dealer today, the mechanic took a test drive with me and said he could feel it - exactly as I described. I left it for them to look for the cause and when they called later that day they said they can't find anything wrong.

I told them the mechanic already said he could feel the vibrations; apparently it was a different mechanic that tried to diagnose it to the one that drove it earlier

I told them to keep it overnight and have the first mechanic look at it tomorrow.

I hate the way they say "no fault" when they mean "we can't find the cause of the fault". They said the engine mounts looked fine - of course they 'look' fine, doesn't mean they are working as they should!

I imagine these engine mounts are much like the control arms - impossible to diagnose while on the car unless they are totally dead because they are so heavy duty they only show up problems under the stress of being in use yet show nothing when tested by hand. Sometimes an educated guess is the best you can do but they rely on fault codes and things being visibly broken before they are willing to suggest something as a cause.

Agree with you.Unfortunately that's how most of the times stealerships come back with universal answer "its totally normal and everything is working as it should be".

If you can get ISTA then you can also try to run smooth running control measurements and you can also measure vacuum at the mounts by activating that function.I think if there is not enough vacuum available to the mounts to shift to hard mode then mounts will remain in soft mode all the time and can cause premature wear on the mounts as there will be more movements.you can even do that test without ISTA by reving the engine upto 1000~1500 rpms and checking the vacuum if it switching on/off quickly and building upto the spec shown in ISTA.