I understand the fan clutch on my 87 is controlled by an electromagnet. So when the temperature got really hot yesterday, the engine temp reached close to 120C. When I shut the engine down, I spun the fan by hand and it had no resistance. Then I turned the key to run without starting the engine, thinking the electromagnet should engage at this high temp. The fan still had no resistance. Is this the proper way to test the fan clutch?
Thanks, Brian

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Brian
87 300Dturbo 180K #14 head still running R-12 SOLD 12/2017
02 F350 Powerstroke 180K
05 Chevy Express 1 ton w/Royal Utility box 120K
08 Infiniti FX-35 40K
15 Golf Sportwagen TDI 35K
10 Sprinter 3500 chassis with a Class A Winnebago on it. 56K

Does it have wires that go to it from a 12 volt source ?
Maybe it has a thermo magnetic unit.. and with the hood up and no hot air going through the radiator it would not be engaged ?
Instead of reading the coolant temperature in the engine.... I am just guessing... I only have 616/7 engine books....

It's not an electromagnet.. it's a thermocouple device.

I guess I better take a good look at it, I thought I remembered reading about a magnetically driven fan or water pump or something. If it's a thermocouple type, it definately should have had some resistance at the temps I was running. Time to order one I guess.

__________________
Brian
87 300Dturbo 180K #14 head still running R-12 SOLD 12/2017
02 F350 Powerstroke 180K
05 Chevy Express 1 ton w/Royal Utility box 120K
08 Infiniti FX-35 40K
15 Golf Sportwagen TDI 35K
10 Sprinter 3500 chassis with a Class A Winnebago on it. 56K

It is not electromagnetic.

It has a thermostatic spring inside that should fully engage the fan at near 100°C. If the engine was near 120°C. and the fan was easy to turn by hand, the clutch is definitely not working.