Hi all,

I am hoping to get some advice about my 'overheating 440SE 2.0lt Auto. I say 'overheating' as i am beginning to suspect a faulty reading from the temp gauge in the car as i have just about covered every possible problem.

Whats happening is on the motorway driving cruising above 70mph, the temp gradually builds up till the needle hitthe red line and the red light starts to flicker, esp in recent hot weather. My car has been fitted with a radiator fan override switch, which i leave permanently on keeping the fan running. As the temp builds up i have to put the heating & blower on to max (open all windows coz its hot!) slow down to around 60 and the temp gauge drops down to mid way. the process repeats as soon as i build up speed again and turn off the heater before i cook.

driving round town the car is fine as long as ikeep my rad fan permanently switched on.

So far i have flushed the whole cooling system inc radiator back flush, replaced temp sender, replaced rad fan thermal switch, replaced thermostat (old one had centre removed so was constantly open) this just caused fast 'overheating' so i put the original back in, new water pump, fresh coolant. The radiator heats up evenly, i.e. no cold spots, The heater works very well, the rad fan does automatically come on but only when the o/heat warning light starts to flicker.

Am at a loss really, i did read somewhere that there can be a wiring problem that messes up with the temp gauge giving false temp readings.

Can anybody savemy day on this? Thanks in advance

J

have you checked how hot the radiator is when this is occuring, are there any areas that the radiator stays cool (or cooler) if so there might be a build up of sludge in the radiator.
It might be worth trying to get a switch from a breakers, but if when you turn the heating on its kicking out lots of heat, then it probably is getting hot, have you tried flushing using one of the heavy duty rad flush fluids, other than that I am not sure.
Grendel

Thanks Grendel,

The rad heats up evenly, no cold spots, have already fitted brand new thermal switch and temp sender. its very strange the fan does not cut in until the red light comes on, i would expect that to happen sooner which is why i suspect the temp gauge to be giving a false reading.
I have already flushed the system but not with a specific cleaner, so i will give that a go.