What temperature rating for fan switch? Zetec silvertop

[SteveRST]

I'm going to fit a fan switch in the top hose just before it enters the radiator. What temperature rating should I go for if fitted in this location? Zetec silvertop.

100c on / 95c off ? Is that too high?

[greenwoo]

had a feeling steve that zetecs were designed to run at around 95/96degrees.....not sure where i picked up that nugget.Have a manual dial one on mine and at the weekend i checked and it was set to come on around 95....

[David T]

I've got 88oC stat plus the Revotec adjustable fan controller set to 95oC, switches off around 86oC. These are readings from the sensor in the stat housing, could be different at the rad end where the controller is.

[Fury1630]

Just a question - why put it in the hose near the rad rather than near the engine? I don't really care how hot the rad is. Can you not put the switch in the thermostat housing? I fitted a brass adaptor to mine & put the switch in that.

[SteveRST]

Yeah Mark, Zetecs do like to run quite hot. The figures you mention sound right.

David - I think the Revotec adjustable fan controller is a good call, rather than guessing at temperature range for a regular fan switch.

Tony - I'm replacing that top hose anyway as it seems to have gone soft and I can see it failing soon. While I was at it I thought I'd finally get an automatic fan switch sorted. The thermostat housing currently has the sensor for the dash gauge and a separate sensor for the ECU.

Ideally the fan should be controlled by the Megasquirt ECU, then I could set precise on/off temperatures in the software, but I just can't get it working. It just doesn't switch the relay like it should - I've admitted defeat and have given up trying to get it working that way.

[andyf]

The turbo sport forum is a good source of information on that sort of question