C107 Heater problems.

[richyba]

I have just bought my first classic Merc - a 280SLC which has been converted to an OM603 diesel from a W124, its a fine job but there are a few fiddling bits that need sorting, one came to mind last night - a distinct lack of heat!

The temp gauge doesn't even flicker yet the rad is fairly hot but there aint a lot getting into the cabin so a couple of questions:

Where is the temp sender on an OM603 engine and will it be compatible with the original C107 gauge?

How are the heater taps controlled? - I'am guessing they are behind the centre console and most likely to be vacuum - any ideas again?

I will be looking at a couple of scrap 107 s tomorrow so might be able to get an idea on how it works before I pull mine apart, of course the other obvious one is the thermostat stuck or not there and I shall have a look at that but it would be reassuring to know if the gauge works first!

Thanks in advance and I will be posting a few not too stupid questions I guess but I try to do my share of answering to so your help would be appreciated!

 

[richyba]

Any ideas anyone?

 

[toby1]

No idea here, but someone will be along

 

[Dec]

Do you have any heater valves under the bonnet like in the link below?
Yours will be different but will have wires and rubber hoses attached either side, pictures of yours would be useful if you can put them up.
http://forums.mercedesclub.org.uk/showthread.php?t=25909

Dec

 

[WG M-B]

From memory the temp sender is located toward the rear of the engine, n/s around cylinder 4. Early temp senders had x1 wire and later ones x2.
The hot/ cold function is controlled by a vacuum operated heater control valve located on the bulkhead [in the engine bay]. You can test the vacuum going to this or operate it manually

 

[Alex Crow]

From memory the temp sender is located toward the rear of the engine, n/s around cylinder 4. Early temp senders had x1 wire and later ones x2.
The hot/ cold function is controlled by a vacuum operated heater control valve located on the bulkhead [in the engine bay]. You can test the vacuum going to this or operate it manually

+1

Hot water flow is supposed to be constant, unless both heat control sliders are in full cold position.

Is it even plumbed in?

 

[richyba]

It plumbed I have found a vacuum valve at the bulkhead which is broken at the operating arm, my guess is that it came from the 124, I have jammed it open and there is heat but it cools rapidly so I'am guessing the engine is running cool, I guess I should obtain a new valve (or better still a S/H one and then maybe plumb the vacuum into the interior sliders. I haven't got the temp gauge sorted yet but it doesn't seem particularly hot so I'am thinking the thermostat would be no bad idea at this stage. I reckon I might need a quantity of vacuum pipe and joiners in the near future!

 

[Alex Crow]

Guessing you might find the thermostat has been taken out...enjoy

 

[richyba]

Tanks for that, that is what I was thinking, are they a bit of a job? The housing looks fairly awkward to get at are they prone to being seized? There aint a lot of room for violence!:lol:

 

[Alex Crow]

Not too hard to do on the 603 really, mounted on the O/S of the block, adjacent to the water pmup.