Intructions for Replacing Aux Water Pump on 602 - PeachParts Mercedes-Benz Forum

shertex · #1 10-26-2010, 09:00 AM

I'm having trouble finding instructions in the FSM for replacing my auxiliary water pump on my 1992 300D....can anyone help?

Thanks.

http://www.w124performance.com/service/Index/602_603index.html

babymog · #2 10-26-2010, 09:21 AM

The aux water pump is held by one or two small hex-head bolts (via a rubber-wrapped bracket), has one 2-pin electrical connector (no latch), and two "heater hoses".

Pinch off the heater hoses, disconnect, remove, replace.

shertex · #3 10-26-2010, 09:23 AM

Where is it on my vehicle?

vstech · #4 10-26-2010, 10:41 AM

I think it's near the air filter.

babymog · #5 10-26-2010, 12:25 PM

It's possibly behind the battery near the monovalve, on the 603 it's under the washer bottle. I don't have a 2.5, someone here who does should be able to tell you.

I just tested and plugged mine back in (un-hooked in the summer), sure gets cold at idle without it.

layback40 · #6 10-26-2010, 09:00 PM

Its on the front right hand side of the motor, just near where the bottom radiator hose attaches to the motor. you can find it by following the heater hose back from the fire wall to the motor.

04 Diesel · #7 10-26-2010, 09:05 PM

Its under the windshield washer tank.

dablk1 · #8 10-26-2010, 11:34 PM

It's under the windshield washer tank. I changed mine out last week. Disconnect the top 2 hoses on windshield washer bottle and remove it. It slides right out. When you look straight down you'll be looking at your auxiliary water pump. There are 3 hoses attached to it. Remove the hoses, disconnect the pump from it's bracket which is also wrapped in rubber; replace.

compress ignite · #9 10-27-2010, 05:08 AM

[Although, the Location shown in the FSM for the "Up to" 11/92 are WRONG!]

http://www.w124performance.com/service/w124CD1/Program/Climate/83-630.pdf

O4 and dablk1 are correct about the location on the Early 124.128.

Did the factory move the Auxiliary Water Pump over to the Mono-Valve location
in late 1992 as pictured in the FSM???
(Or are we all victims [Once Again] of the Hybridized 601/602/603 FSM ?]

shertex · #10 10-27-2010, 07:04 AM

Quote:

Originally Posted by dablk1

It's under the windshield washer tank. I changed mine out last week. Disconnect the top 2 hoses on windshield washer bottle and remove it. It slides right out. When you look straight down you'll be looking at your auxiliary water pump. There are 3 hoses attached to it. Remove the hoses, disconnect the pump from it's bracket which is also wrapped in rubber; replace.

When I remove the hoses, will I lose a significant amount of coolant, or is it not a big deal?

And just 2 hoses, not 3, correct?

babymog · #11 10-27-2010, 09:12 AM

Significant? Just clamp both hoses and you'll lose a cup.

If you don't have the $5 hose clamps, use vice-grips and a couple of short pieces of wood.

shertex · #12 10-31-2010, 06:54 AM

Quote:

Originally Posted by babymog

Significant? Just clamp both hoses and you'll lose a cup.

If you don't have the $5 hose clamps, use vice-grips and a couple of short pieces of wood.

What is the best tool to have to crimp the hoses? I saw on Harbor Freight site some grip pliers....seems like there should be something better suited.

shertex · #13 10-31-2010, 04:21 PM

SUCCESS! Was able to install the auxiliary water pump this afternoon.

Just in case it may help someone else, here's what I did:

1. Thought I would need some clamps but I didn't.

2. Loosened both hose clamps.

3. Left the protective cap on the outflow hole of the new pump.

4. Quickly removed inflow hose from old pump and attached to new pump...lost minimal amount of coolant and cap prevented any coolant flow.

5. Removed outflow hose from old pump and quickly removed cap and attached to new pump.

6. As old pump could not be removed from bracked while in car (too tight), I removed bracket and old pump in order to get pump out of bracket.

7. Put new pump in bracket and reattached bracket.

Now I've got blistering hot heat at idle....ready for another New England winter!

Thanks for all your help, guys....really do appreciate it!

dablk1 · #14 10-27-2010, 09:23 AM

Coolant loss will not be significant. There are 3 hoses. If you have the replacement part in your hand there should be three holes(connections) 1 at one end and 2 on the other. Hoses attach to these. Also keep in mind that there is a small modification on some of the pumps. It's the placement of the power connector... Some are attached with a wire extending from the pump and the other is attached directly to the pump.

dablk1 · #15 10-27-2010, 09:26 AM

Actually I stand corrected. I apologize. There are only 2 hoses, the third connection is for the power source. There are 3 connections, 2 hoses and 1 electrical.