Are your thermostats working

[BAR]

Having driven my car very rarely this summer I finally became suspicious that my thermostat wasn't functioning.

There are two thermostats that will turn on the Auxillary fan [electric unti in front of the radiator]. One is on the A/C receiver/dryer [near the A/C condensor] which will switch the unit on when the A/C fluid temp is >80 deg C and the other is on top of the water pump and will switch the unit on when the water temp is too high [there are two different units and temp is dependant on which one].

As I found out, it is easy to test the operation of the A/c switch as one can simply put a heat gun on the unit and see if it switches on. As for the water temp unit, well I couldn't get enough heat to the thermostat, but did notice that it obviously wasn't working when the engine temp guage read over 110 deg C.

WHilst waiting for a new unit to be supplied by Styria, I have bypassed the A/C thermostat and joined the wires together: so for the time being it will always be on.

 

[Martin280s]

For the cooling circuit, I use the thermostat from a Mercedes-Benz 608 light lorry/truck. I forget the engine number now.
However, this thermostat, or "Onion" as they call it in Brazil, opens at 73C. It may seem too low but in high ambient temperature environments it is very handy.
Coupled to the 3-row radiator core I had made up and 12lt water capacity (against the standard 2-row/11lt system), the car never goes anywhere near 95C which it did before these simple modifications.

 

[WGB]

The usual water temp switch as I understand it is the 110 degree one but they also make a 100 degree one as well which I had fitted to a 126 after I had heating problems.

If you need to do more than that on a reasonably functioning system I would suspect head gasket/fan hub/radiator blockage etc.

An advanced ignition will also increase water temp.

Bill

 

[Styria]

Hi guys, I can't make any comment regarding the switch that is located near the Receiver/Dryer.

The switch that is screwed in atop of the thermostat housing is a 100 degree switch - as on 6.9s and more than likely on 450s as well. It is, however, possible to substitute that switch with an 80 degree unit which is what I have on 'Gleaming Beauty'.

Personally, I don't see "a lot" of benefit when the additional electric fan comes into operation. Naturally, whilst it's there, I'll leave it. To my way of thinking, a good radiator, well working thermostat and efficient clutch fan appear to be the more desirable option in keeping a car running during hot weather conditions. Regards Styria