i have a coolant drip coming from behind my fan pully and am
considering a new water pump. i have never done this job but
it seems straight forward from what i have read. i have the 280ce with a 110 engine and a viscous fan coupling. i have a couple questions. is this a job i might regret doing myself, or being a handy do it yourselfer will i be within my abilities? and second, when replacing the pump, naturally
i will replace the gasket from the pump to the water pump housing, but what about the gasket between the housing and the block? should i replace this as a matter of routine?
will i be able to see if it needs replacing once im looking at it? is the other gasket( pump to housing ) the usual culprit? thank you all for your imput.

greg stein

I recently did the same repair to our 300SE (126). I'm not sure how your pump is configured, but but here's my experience.
The one for our car came with fresh o-rings so gasket replacement isn't a issue. By the way get one from Fastlane, in addition to helping our hosts, it's OE and you don't have to worry about the core.
I found this job to be a real pain in the rear, had to remove numberous pieces that aren't defined in service cd. like: radiator (to access viscous clutch), all pulley's, belt tesioner, power steering pump. All this to get at the four bolts that hold this rascal on. Additionally my CD said to remove the AC compressor, I did but you don't have to do it.
That being said just budget a few more hours than you expect, take your time, and the job is not difficult. Also be sure and change the themostat while you're there. Hope this helps.
Steve

I have replaced the water pump on my 124, and 115. Of course, the 115 was much easier to change, I also replaced it with new belts, themostat, and transmission lines.

Only the radiator, fan removal, and loosen the PS pump was all it takes to do the job

jack

Steve,
If your car is the 280CE with the 123 chassis'78-'81 model, replacement is fairly easy. It is mounted on front of the engine block and easy to get to.The hard part is getting those four 10mm screws off that holds the fan on.
The pump is what we "pros" call a four hole long nose pump. The part no. is 110 200 09 20. They cost about $36 and come with a gasket. I could be wrong and your car could take the short nose pump, so have engine no. at hand when you order the pump.
Bill lewallen Lexington,Ky. Home of Valvolene Oil-Maker of Mercedes Glysantin G-05 antifreeze....