MBDiesel.net - An Owner's Journey

Just finished replacing the vacuum pump on the 240D today.

Yesterday, after completing my first oil change with my new MityVac topsider, we started the car up to check for leaks, etc. I kept hearing a faint sound coming from the front of the motor towards the driver's side - kind of like tink ta-tink tank. Very random and staccato, no real rhythm to it.

I really wish I had a true mechanic's stethoscope, but in a pinch, an 18" quarter-inch drive extension will do the job adequately.

I first checked out the power steering pump. Nope, not it. I was still hearing the noise in one ear, but not the ear close to the improvised stethoscope. Then, I checked the vacuum pump.

Bingo. Noise in both ears.

Then I checked around that area of the block, and was back to nothing. Nothing on the injection pump side, either. Back to the vacuum pump, and there it was. Tink ta-tink tank. Subtle, yet easily heard with the hood up over the noise of the motor. Then again, our 240D is considerably more quiet than your typical 300kmi clatterbox - she should be, as the motor only has 34k on it!

So, we parked the car and this morning I ordered a replacement vacuum pump. We put it in this afternoon, and everything is back to normal.

Upon removal, the bearings on the rocker arm showed signs of excessive wear, and the roller between them had severe lateral play. She wasn't long for this world.

When I have some free time this weekend, I intend to disassemble the old pump and take some pictures. Been a while since we've had a photo update of some kind around here!