c240 waterpump

[chatteris]

My 1998 c240 needs a new waterpump, is this a simple diy job? is there anything to look out for. it looks like the pump forms the front mount for the alternator, and I am not sure how the tensioner is loosened, any tips gratefully received

 

[thedoc01]

Dont know about the 240 mate but ive just spent 9 hours on the same job on my 300 coupe.the tensioner on mine looks like a hole for a dipstick or something, some have or should have a plastic cap on them. It has a hexagonal head tho and you turn it anticlocwise to slacken off the auxillary belt. Its just to the right behind the thermostat housing. Im no expert but i hope this helps. neil

 

[grober]

Here's a diagram WATER PUMP ENGINE COOLING SYSTEM
Getting access is the problem. This a thread with a link to DIY pdf --illustrated. It refers to a M112 [your engine] in a different vehicle but should be roughly the same I think??? e.g ordinary bolts may have been replaced by the torx type in later engines
DIY - Coolant (water) Pump - Benzworld.org - Mercedes-Benz Discussion Forum

 

[chatteris]

made a start on it today got pump off after a bit of a struggle with the fan,bit unsure now new pump came with paper gasket but my car has a rubber seal that fits in a recess on the block,without the seal there is not a lot for a paper gasket to sit on so wondering if I should put rubber seal back in with a bit of sealer and maybe use paper gasket as well or more sealer,

 

[horgantrevor]

I would use rubber seal if it's ok and a little paste also remember to put all bolts in and then tighten up checking the seal before final tighten

 

[chatteris]

old seal is intact so will reuse with some blue hylomer, there was a fair bit of play in the old pumps bearing,surprising as it was only dripping slightly when I looked at it when it started making a noise.

 

[chatteris]

All back together now,car has done 116,000 miles so I suppose thats not to bad although I have had other makes go alot further without needing anything done, have been trying to decide if to trade it in as I could do with a large MPV to cart the ancient relatives around but have been dithering a bit.