Hi, I've replaced my water pump yesterday but snapped these pics to post on a forum. Now I'm having second thoughts. The rust spots are actual housing rusting through, not the rust left from the water pump motor.

I'm going to be doing a citrus flush next weekend (if weather is good) and I figure maybe better to fix this item than be sorry for it. Of course, I can't seem to find the part on any of my typical MB parts online stores...

BTW the new element on the water pump is hard plastic as opposed to metal. I wonder why they changed it

I'm also going to build a "special" tool to hold the pulley in place while taking the fan off. For some reason I didn't think of this beforehand and had to improvise with hex tools almost stripping the holes in the new pump wheel. But now I'm going to grid out a piece of metal, drill two holes and put two studs in them so that I can securely hold the pulley by both holes.

Attached Thumbnails

     

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1992 W140 300SD
1982 W123 240D
and others non MB vehicles...

Why do you think the housing is rusting thru? I don't see any holes in the picture.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

X2!

I have never had my Water Pump off yet. They reall make a nice Impeller; much better than the normal stamped Sheet Metal ones on most cars.

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84 300D, 82 Volvo 244Gl Diesel

Well when I scraped off some of the rust I couldn't get those spots to shine again like the rest of the housing. I looked closely and it seemed like the rust was actually of the housing. Not the deposit from the propeller.

However, it's very possible that the aluminum housing part (which I believe to be aluminum) does not rust that way and what I'm seeing is in fact a deposit from propeller. I'd be content with that.

Now that I've searched through 5 different online parts places I can't find anyone that's carrying this (6032010801) so I'll just leave it be.

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1992 W140 300SD
1982 W123 240D
and others non MB vehicles...

I am not an expert on this. Basically, plastics have come a long way, since the 70's. I do deal with automotive parts on a design level, but not at any level where I would consider my opinion as 'expert'. The key to changing to plastic is usually cost. Although sometimes metal parts are cheaper. Also, sometime plastics give better performance. I don't see where the impellor of a water pump takes high stress. I also see the advantage previously noted as not to corrode or rust.
Tom

plastics do break, as in 2000 VW jetta water pump, I do not know if they are the same plastic

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2010 ML350 Bluetec
2012 Mustang Convertible