I was changing the tie rod ends the other week. I had the front of the car raised on jack stands. Every couple of moments a stream of water would drop off the front of the oil pan. It had rained the day before, and I thought it was just accumulated water. However, the stream, about a second or two, kept happening. It looked like it was coming from farther up the front of the block, but I could never see the source.

I know I have a leak at the water servo thing on the passenger fender well. I've had to add water to the radiator. I've noticed that the temperature gauge fluctuates also. I think now it is a bad water pump. I hear no squealing noises.

Are there any special steps in changing a waterpump on a 300d? I've changed them on v6 GM's and Ford small blocks. Just don't want to get into something that requires a special tool or 'trick' and not know before hand.

 

Thanks mate!

 

While you are doing the Water Pump replace the short Bypass Hose. It is about 2.5 inches long and about 2-1/8 inch inside diameter.
Prior owners seldom replace that Hose like they might do with a Radiator Hose because you need to take apart part of the left side of the Thermostat Housing to do that.

The Metal under is frequently eaten up. That happened on Mine. I ground out all the surface corroded metal and filled the grooves in with JB Weld Epoxy and filed and sanded it smooth so the new Hose would Seal Well.

Note that is also common for the Bolts to be corroded in on the Cooling System. Work with as much caution as you can.

If the little Aux Electric Water Pump is leaking and you don't plan to replace it you could disconnect it and replace it with a section of Heater Hose.

Also depending on what type of Climate Control you have a defective Aux Water Pump has been know to burn the Climate Control Module and that has started at least one Car on Fire. There is no Fuse in the Aux Water Pump to Climate Control Circuit.

 

What a cluster! Two of the bolts that hold the fan to the water pump rounded off. I had to cut them off. Then all but 1 of the bolts holding the water pump to the aluminum housing broke off. It looks like I'll have to take the crank pulley off to get the bottom bold on the housing off.

Needless to day, I'm not happy at the moment. Not sure I want to pull off the crank pulley or just haul it to a shop.

Any one know where to get the housing the water pump fits into? Also a fan shroud? It broke when I took it out.

 

This is not helpful but a lot of others have felt Your pain when removing Bolts from the Cooling System parts.

Concerning the Parts you want; I believe there are still Junk Yards that will pull off the parts for You. If you do that be sure they don't give you one with a bunch of busted Bolts in it.

Another way would be to Google looking for Mercedes Forums and see if you can find someone local that has a Parts Car that would be willing to sell the parts.

Ebay sometimes has those parts and I have seen new Housings that you want but they are about $275 each. That seems expensive but to have a Mechanic deal with the original you have would also be expensive.
Also the Aluminum Cooling Systems parts are often eaten up due to electrolysis or corrosion.
I am not sure if the parts for the 1980 non-turbo are the same as for a Turbo Diesel like My 84. My guess would be they are not the same.
I was looking a bit and you man need to supply your Engine Number (on the Fuel Injection Pump side about in the middle right where the Black and Cylinder Head come apart) as apparently there could be more than type used in the same year.
Also often Mercedes puts the Part Number on the Part.