Driving on the road my 84 300TD certain times climbs to 85-90 C but it just sits there. One thing I've noticed is the aux fan never comes on. Is it suspposed to kick on at a certain tempature?

Your car might be of the vintage that the aux fan is only triggered by AC refrigerant pressure or temperature.

Your fan clutch might be tired.

Sixto
98 E320s sedan and wagon
02 C320 wagon

It is. But the controlling factor is refrigerant temperature, not coolant temperature.

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How is the a/c working?

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Jim

AC doesnt have refrigerant.

I just checked under the hood and the fan clutch starts up instantly. I think I might have a bad radiator in the car

I would not consider that a problem. That temp range is within the design regulatory range of the thermostat, which doesn't fully actuate until reaching 94ºC.

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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.