Air Pump making muffled noise

I have a 90 300E 2.6 that has started making a muffled noise somewhat like an exhaust leak. It appears to be coming from the air pump. It cycles on and off during idle.

Can anyone help me with this problem. If the air pump need replaced, where can I get a rebuilt one. Doing a quick online check to the benz bin indicates that a new one will cost $676.

[Mr. BILL]

Do a search, someone recently posted they bought one for $290.00. That's what I paid for one a month ago. Call Texas European Auto Parts. 1-512-873-0586.

[Todd LaRoche]

German Star is a good source. Has rebuilt air pumps with 1-year warranty for $325.

[pmizell]

gman1:

Have you ever had an oil leak near the AIR pump? (head gasket or timing cover leak?) I had that muffled noise as well, until I discovered it was a bad rubber elbow hose that connects to a metal pipe which in turn goes to the head. (oil had expanded and ruined it) There are actually two of them down there and they are elbow shaped.

Check those for leaks before you conclude that your pump has gone bad.

Good luck...

~Paul

_____________________
'91 300E, 208k miles