I have a '73 280SE 4.5.

When is the electric fan mounted in front on the radiator supposed to come on?

I was driving the Red Baron yesterday in 100 degree heat, and at idle with the a/c on, the temp gauge would start to climb close to the red.

When I got home, I let it idle in the garage to see how high the temp would get, and it got right up to the red mark and stop, which is clearly too high.

I notice the electric fan never came on, and it got me to thinking that it should come on when the a/c was on or when the temp got to a certain temp.

In any event, neither the a/c on or the high temp triggered the fan.

FWIW, the radiator is newly recored.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".