AO Silver Member
Join Date: Feb 2005
Location: Auckland, New Zealand
Re: temperture light.
I think the point that the fan comes on at is controlled by the switch in the radiator end tank. It will vary a bit between cars I imagine.
If your engine temperature drops down to 40/50 when you're coasting along, I imagine your cooling system thermostat has failed and is stuck open. This thermostat is supposed to trap coolant in the engine when necessary to maintain engine temperature, then allow it to flow through the radiator when the motor needs to cool down. But if the thermostat jams open (this is the way they're supposed to fail), coolant will keep cycling through the radiator and in some situations will cool the motor down too much.
You should fix this because it could be costing you petrol and causing more wear on your engine.
Originally Posted by 73GTVJim
"PS and you agree with Ben so you must be wrong