Zag7er

Hey guys recently my M103 has been going through WAAAYYY too much coolant lately and heating up very quickly, not quite to the red but between 90 and 120. I'm not sure where the leak could be coming from as the reservoir doesn't appear to be cracked and all the hoses I can get to without a hoist seem to be in good shape. Nor do I believe it's the head gasket as the PO replaced it prior to me buying it (the guy traded a MKII Golf to his mechanic to do the job). My thoughts are it may be the water pump? But again I'm not going to get a chance to put it on a hoist until Sunday. There's been drips under the middle of the engine and when I park it lets out whatever's left. Have any of you had issues like this and what's the best way of diagnosing the problem. If it helps it's a euro 4-matic. The radiator also seems to be in good shape as well. But I mean I could pour a whole jug of coolant in and the light is still on saying I'm low... Plus just today my heater stopped blowing hot. Thermostat problem maybe?

On the upside I did find out factory Mercedes coolant is like $15 cheaper than the factory stuff for my old E32 7-Series
Hope to hear from you gents soon

Mike.

Plutoe

Well as you know the engine coolant and passenger heating system is a closed system.

If like you say, you are losing loads of coolant---it has to be going somewhere--the space under the car will be wet-------the interior foot wells will be wet----you may notice that the interior fogs up because of excessive moisture-----if none of these things are a foot, then you have spent too much time at the pub or your buddy did not replace the head gasket!!

Argus Panoptes

It could also be leaking from the water pump bearing, the weep hole, or from between the block/water pump. All three of the above would call for a new pump (p.I.t.a)
The heater probably isn't hot anymore because there is air in the heater core, which you will have to bleed out.

Zag7er

Thanks for the help guys. I'm more inclined to believe its the water pump since there's no other symptoms of it being a head gasket issue.
Is there a DIY Link for the waterpump replacement on here anywhere?
Btw I looked up photos of that pump.... Does look like its gonna be a PITA

Argus Panoptes

Sure man, http://www.peachparts.com/Wikka/M103WaterPump there's your link.
Make sure you get the small hose from the pump to the head. Its cheap and saves yourself so much trouble if you just do it while you're already there. Also extensions and elbows. Do yourself a favor and buy a set, I used every size extension available to me during this job.