ML350 4matic 2014, 20, 000 miles approx. I have a squealing noise coming from the engine once it's warm (approx 15mins of starting the car). I have removed the belt and noise was still present.

We've checked the pulley's, throttle, done a smoke test to see if there are any cracked pipes/gaps but yet nothing. Can't see any oil leaking from anywhere either.

My mechanic says it's due to a leakage from the vacuum hose intake that comes directly out of the engine and that he would have to "drop the engine" to rectify the problem. However, there is no oil on the surface of this pipe nor are there any visible cracks. The engine isn't shaking nor is it noisy.

I am horrified and reluctant to give him the go ahead.

Has anyone else had this problem?

 

I'm having the same issue right now. Unexpected VERY LOUD squealing noise came out of nowhere right after I stopped and re-started 2 minutes later. Sprayed a whole can of WD all over the belts and pulleys. Popped a P2279 CEL so I changed out the little green O-ring on the intake that you can get to at the front, looks like a PCV valve but that didn't fix it. Not sure what else to do, but I've had the car all of 3 months now so back to the dealer it goes and if they can't fix it they can keep it. Back to BMW if this is how the Merc rolls.

 

First post was about an ML350. Second one only clue is he has a 97 E320. This is the GLK (X204) forum guys