The high speed radiator fan comes on before I expect it when I am stopped in
traffic.

This can occur  well before the needle hits the LED.

The system will run with needle in the middle of the LED on warm days, so I
think the gauge is good.

I have replaced the fan switch and it acts the same.

I have a bleeder valve on the radiator, with a tube into a jug of water. The
system doesn't push air out, just coolant.

So I am asking if the radiator itself can go bad in some way where the fan
switch sees hotter temps than the circulating coolant?

I didn't think the radiator would trap air any place except at the top.

And then. it doesn't happen all the time.

Thanks for any help.

Tom Salicos

'87 Syncro Westy w/EG-33