B200 CDi CVT strange noise

[peckerpecks]

Hi I am hoping you can help me. I have a B class and its started making this whining noise which increases as the revs increase. You can't hear it when at idle in drive but as soon as you set off it gets quite loud. It sounds as though it's coming from underneath the car. No warning light are on the dash but the car doesn't seem to have as much go about it. Also there is a warm smell of burning, kind of like a hot metal smell through the vents. The engine is at normal operating temperature. Any suggestions most appreciated. Forgot to say car has done 147k and it has full service history.

 

[MickyP64]

Our A200T makes the same noise with exactly the same symptoms (no burning smell though)…it’s been that way since we’ve owned it (third owners)…I’ve heard other W169’s making the exact same sound as well…interesting that your car has just started to make that sound too.

I’ve wasted hours searching the web on various forums for anything CVT/noise related and haven’t been able to find anything that will give me a conclusive answer as to what’s causing it… I’ve come across various theories ranging from it simply being a feature of the CVT through to it possibly not being the CVT at all but pulley/belt/pump related instead.

I have a thread here: http://www.mbclub.co.uk/forums/engine/165278-cvt-noise.html

It does irritate me sometimes but I decided to stop worrying about it unless something breaks – it’s been about three years so far…We’ve driven the car to Munich and back, Essen and back and the Southern France and back without any problems.

I am planning to get it looked over by the chap in West London who seems to be a bit of and A-Class specialist and seems to have a very good reputation (though I think the W168 is really his thing)…just need to find the time!

 

[John]

Our Juke with CVT started making a noise at first - then it started to jerk like it was hunting for a gear (even though it is one gear on a CVT).

It also smelt a bit odd if I remember rightly.

It had around two months left on the warranty so I opened a large can of "whoop-ass" on the gearbox (via the accelerator) to speed up the demise!

Luckily it failed shortly after.

However, with an example of a CVT with the same symptoms on the same make of car would suggest it could be nothing to worry about.