Hot Thunking Mercedes E350



Hi Everyone

I have a 2006 Mercedes E350. The car operates normally except in hot weather! Whenever the temps climb beyond 70 degrees, I start hearing a thunking sound in the front of the vehicle as I’m slowing down or stopping. This also occures at slow speeds such as starting from a stop sign and if I turn my steering wheel from side to side. But it only happens in hot weather. The hotter it gets, the worse it gets.

I have taken the car to 4 dealers and they can’t find the problem. They can hear the sound but can’t diagnose it. They have replaced the rack and pinion, the struts and the bushings, but it’s still making the sound. Could it be they replaced a defective rack and pinion with another defective part?


Still thunking in San Francisco


This thunk…

…does it happen just once when your braking or moving from a standstill ?

If so, it’s a bush or rubber mounting somewhere, the heat is shrinking or expanding it enough to manifest play. The only real way to diagnose it is to get under there with a big pry bar when it’s hot and lever away until you find it.