I plugged a 12V test lamp into the aux pump connector and it lights up with ign and climate control on. so far so good.

I got the water pump off and it came off as two pieces together and I had to take the Super Charger belt off to get it out. Is this the normal way to change the water pump? Do you split it and put the new pump on the old housing? The one I ordered, (MasterPro Water Pump - Water Pump Line: MWP | Part # 58-612 for $44.99) says it comes with a gasket but did not say two gaskets. Do you normally get both?

The impeller in this pump is plastic, but a hand engraved number on the face of the hub makes me think it is a rebuilt pump. It doesn't appear to have been leaking and the weep hole was on the top, not the bottom, and didn't have any coolant in it.

The third, fourth, and fifth pics are from the O'Reilly's web site. Does this look like the right pump?


I called O’Reilly’s and the guy assured me the pump i ordered comes with two gaskets.

 

Yeah, the bigger clip was easier to get to. The one on the bottom of the expansion tank was harder to reach. I couldn't get at the bottom leg and was trying to push back the top leg with a long screwdriver but it kept snapping back into place so I pushed it all the way off thinking it would just drop into the pan I was using to catch the coolant, but not so lucky. I have until Tuesday when the new pump comes in to find it.

 

My old pump with old gasket still in place. My new pump looked the same except for metal impeller. I only had to swap over the pulley.

 

My steel clip was missing compleatly when I purchest my car , it had four cable ties holding the pipe to the expantion tank is an awquid fashion , I purchest a new pipe to replace the clip then found the clip many monthes later ,
It will be in the fan shroud as mine was also. You can carfully prize the shroud open a little at the bottom edge and it will hopefully drop out . I purchest the compleat GMB up grade pump for mine it was two piece but assembled in one piece on arrival . and a steel prop . $170nzd

 

Thanks, guys,

I feel better about the pump I ordered now. The EPC shows a pump and an O ring - completely different.

OK, I'll look in the fan shroud if I can't find it underneath. Reminds me of a time many many years ago when I looked for hours for something I had dropped and finally found it in the cuff of my Jeans. Remember when you just rolled up the legs of your jeans that were too long? seems like another life time now.

 

This is getting pretty far from my original question about starting the engine with the MAF disconnected (which I then didn't do), but I searched the archives and found a post listing an excellent article about Aux pump brush replacement at:

Auxiliary Water Pump Funcitionality - Page 5 - Mercedes-Benz Forum

I ordered new brushes for my Aux pump that turned out to have brushes worn very short and not contacting the armature. Looks like a relatively easy replacement with exactly the right brushes, but I bought four just in case I screw one up. $25.50 for brushes is better than $$$$ for a new pump or $$ for a used one that might not last very long.

And after looking and feeling around for two days and not finding the keeper wire for the overflow tank connector, my wife took a look and found it in three minutes. I don't know how I didn't see it laying behind the super charger belt tension arm - it was obvious when she pointed it out. She said, "Well, I'm Choctaw and Indians like shiny things."

So now I just have to wait for the new water pump and the Aux pump brushes and then put it all back together and cross my fingers.

Almost forgot. Anyone know of a source for whatever O ring is used in that big plastic connector on the bottom of the thermostat housing? That is my main leak suspect now.