Vac Pump?

[mark82]

Noticed an oil leak under air cleaner and clear line from vac pump was black. Opened air cleaner and it was oily inside with filter wet with oil. Temp rerouted air line to ground and ran it, leaves a puddle of oil on ground.

My assumption is the diaphragm is broken allowing oil to exit the pump via the outlet line. But thus far the vacuum seems to be working fine.

Assuming the oil level is kept in the normal range, is this a drivable thing?

Is there likely something more serious than the diaphragm (standard rebuild kit) broken?

Two-hose type pump, 79 240d

Is it true that the newer single hose pumps can no longer be rebuilt?

[BWhitmore]

Single hose vacuum pumps can still be rebuilt but the cost of the parts alone (if you can find them) is equal to the cost of a new genuine Mercedes vacuum pump. As a general maintenance item I change the vacuum pump every 125,000 miles. Having seen a few pumps explode internally with no warning and also take out vital engine parts, the cost of a new pump is well worth it.

[barry12345]

Well you can no longer feed the exhaust of the vacuum pump into the air cleaner. For several reasons. You have no way to determine the additional increasing oil that will be pumped out of the engine in service either.


Just rebuild the vacuum pump. The pump will probably totally fail in creating vacuum as well at some point.

[mark82]

Agreed on both parts. I am daily checking the oil level and hoping to get it through the weekend until the rebuild parts arrive.

Just wanted to check that the oil blow by is symptomatic of pump failure and not some more major issue.