Three questions, temperature 1984 300SD
 

1984 300 SD

1/ The switch on the thermostat housing is it normally open
when cool

2/ At what temperature will it switch.

3/ Will it turn on the Aux fan when engine goes a higher than safe
temperature.

OK I lied, 4/ Does it have anything to do with the heating
system.

I was thinking name, quest, unladen velocity.

Dont forget 'favourite colour', and..." is that an African or European Swallow? "

/Hijack

1) Correct.

2) 50°C.........IIRC

3) It does not run the auxiliary fan.........it runs the blower in the cabin.........prevents it from dumping very cold air on the driver and passenger.

4) Yes, it does.

Thanks Brian. I was hoping there was a way to get the Aux fan to kick in when the engine starts to get to 100c.
What are Moon161 and Renntag going on about?

One option is to retrofit a red top aux fan switch with a 100*C setpoint from a 102 or 601 engine. Here is a 2-pole red top 100*C switch from a 102 engine -

http://catalog.peachparts.com/ShopByVehicle.epc?q=&yearid=1986@@1986&makeid=63@@MERCEDES+BENZ@@X&modelid=6127:ED|10000009:SM|846:M BC|1484@@190E+2.3&catid=240909@@Cooling+System&subcatid=241005@@Auxiliary+Fan+Switch&applicationid=W 0133-1630156&mode=PA

Here is a gray top 3-pole 105*C/120*C switch from an early 602 engine -

http://catalog.peachparts.com/ShopByVehicle.epc?q=&yearid=1986@@1986&makeid=63@@MERCEDES+BENZ@@X&modelid=6127:ED|10000009:SM|846:M BC|1484@@190E+2.3&catid=240909@@Cooling+System&subcatid=241005@@Auxiliary+Fan+Switch&applicationid=W 0133-1625972&mode=PA

Fastlane doesn't list the red top 3-pole 100*C/105*C switch I pinched from a 601 at the yard.

You must have been raised in a cave if you're not familiar with -

http://www.youtube.com/watch?v=IMxWLuOFyZM#t=2m0s :D

Sixto
87 300D

The Gears, Watch "Monty Python's The Holy Grail " and you will get it.

What? I don't know thaaaaatttttttt.....

Thanks for the switch info Sixto.
OK I get it "3 questions" Ha Ha!
When I was growing up Monty what ever his name is had not been invented.
I will change to a 100c temp switch, run a wire from it over to the connection for the AC temp switch. The AC temp switch will function as designed. I think.
As for the cabin heater I will permanently ground the original heater line to tell the cabin heater the temp is up and can turn on the blower.
Hope this all works.