Hi Merc Gurus.

I have a mercedes 190 E 2.0 inj, 1993 with approx 104K. The car runs great and performs well. A couple of months ago it developed a problem with the heater. Still have theproblem and would like to sort it out myself as my local Mercedes specialist would charge approx. £300.00 to fix it. Problem is that the heater only seems to blow out luke warm air on defrost, if the flow is directed to pedals or cabin, air is pretty cold. In winter it makes it an unconfortable ride. This is what I have done so far:

1. Flushed system and replaced antifreeze
2. Replaced duo valve
3. Replaced thermostat valve
4. Checked for leaks and no leaks
5. Checked input into heater exchanger (water enters hot and leaves hot as far as i can make out)

The engine runs between 80C and 90C which is around normal. Would like to see a functional diagram of the heater system to work out what is going on. I have an Hayes guide however it does not go into much detail on workings.

It is not A/C so the whole thing should be quite simple.

Any help appreciated.

Regards
dean

 

Hi,
I don't know if yours is similar to mine or not but on mine there is an auxilary motor for the heat. It circulates the engine water through the heater core. Mine is mounted on the passenger front fender, under the hood. I had voltage to mine but the motor was not turning. I repalced the unit (comes with motor and pump) and it works great.
Jim

 

Hi Gurus,

Just an update. Found out what the problem was. The heat exchanger was blocked.

Used some radiator cleaning solution first (left in for about a week) then I disconnected both ends (head and water pump hose) and connected a jet washer to the head hend, turned it on and out came a load of sludge. I did the same by connecting the jet washer to the other end and another load of sludge came out. It is now the most efficient heater in the block. Warns the car up nicely on chilly mornings and keeps my sceen mist free.

thanks for your help.

regards
dean