Hi All,
I have a '07 e350 W211 (base) with 73,700 miles. Purchased as a CPO with 40,000 mi. It's been a great car with only minor issues so far. The warranty has expired so let's get it fixed. I be a DIYer and have been wrenching on cars and anything that breaks since I was 16.

The ISSUE: This morning I drove to the store and was inside for 20 minutes, when I came out I heard some kind of fan noise while the engine was shut off. I knew that was unusual sound from the engine compartment. Drove home with no warnings or check engine lights on the instrument panel. I popped the hood and stuck a screwdriver to the A.I.R. pump and the handle on my ear. It was running at a steady high RPM, then after about 10 minutes it slowed down to almost nothing, speed up a little and then finally shut off a few minutes later.

From the forum posts I read and a MB mechanic I called, it is presumed my secondary air pump (A.I.R.) and its relay have bit the dust. There are three fuse panels on the car. One on the left side of the drivers dash (fuses only) and the second in the trunk (boot for the English) compartment, left side area which has some fuses and relays, and the third, under the small plastic cover (drivers side) fuses and relays. I have not yet determined which relay it is.
The new relay and a new pump — $14 + $640 + tax.

It looks like an easy removal and replacement due to its location right in the front at the top of the engine. Any use for the old pump, i.e. core?

I would appreciate any suggestions, comments, do's and don'ts and advice that the forum can offer.

Thanks!

Thanks Kinigstiger for the great info/diagrams and link to the part which is priced low!

 

Part # 0001405185, R relay 0025421319 @ front SAM (engine compartment) $180/free shipping https://www.amazon.com/Mercedes-w164...g=everybenz-20

 

That's an awesome price. These are about $600 form the dealer.

 

Thanks for the help King,
I am still waiting for the part to show, UPS tracking says July 6.
I have another question. Does it damage the new relay I installed if I haven't removed the old non working air pump yet? I believe the old air pump is seized and the check engine light has come on after my initial post. Secondly, once I have installed the new air pump, will the check engine light need to be reset by a technician or will it go off? Last, how do I determine if my engine is the 272 or 273?
Thanks!

 

Probably not but anything is possible.

Should clear.

272.964

Check PM.

 

This relay is not too expensive to replace. Will this relay work for my car?

Thanks,

 

Yes, 0025421319.

 

Thank you,

 

Relay contact welded closed, it was specified a little small for the application.
When you are lucky they fail open...
Anyways, for future reference you can have the pump refurbished or refurbish it yourself if you know your electric motors although 180 is a pretty good price.