Mk3 Cavalier Owners Club | Vauxhall Cavalier Dot Com

The radiator fan on my 1993 Cavalier V6 comes on erratically and, I think, more than it should. Even in cold weather, when I stop the engine after a run it comes on for a several minutes. I have done the obvious thing which is to replace the fan switch screwed into the side of the radiator, but this has made no difference. I can only think that the relay is faulty and operating without an input from the switch. Does anyone know where this relay is located, or have any other comments on this problem?

Hi, I had a V6, and I'm pretty sure the said relay is in the engine compartment relay/fuse box near the bulkhead. I can't remember which one it is but I did replace mine before to no avail as it didn't solve the problem.

Could be the resistor on yours that is playing up, and there are also 2 other temperature sensors located near the inlet manifold. Cheap enough to replace if you are troubleshooting it.

This mite be a silly question but when was the thermostat replaced last as it could be stuck either open or closed ?

Thanks for the replies. I suspected that the relay would be in the engine compartment box but there are 4 of them located there and, unusually, no key to their function is printed inside the lid. They all look the same so I guess i can get a new one and try progressive replacement, one by one. As for the thermostat, this hasn't been replaced for quite a while, but the top hose gets hot a little while after starting the engine so I guess it must be opening OK. It's also a pain to replace so I've left it alone for the time being. Also, the fact that the fan starts up after a short run suggests that the switch (which is located in the radiator 'top' tank - located on the driver's side of this side mounted radiator) suggests that hot water is getting to the radiator OK.

Just a quick one, do you notice the temperature gauge and what it reads when the fan comes on and off?

The temperature gauge only ever gets to about halfway between cold and the mid 90 point however long the car is driven, at least during the current cold weather. I haven't driven the car in hot weather for a number of years as I've only just got around to putting it back on the road. There doesn't seem to be any movement of the gauge that is dependent on whether the fan is on or off. I do intend to replace the temperature gauge sender located in the 'V' of the engine in due course but I don't that that will effect the operation of the fan.

If you're driving in heavy traffic a lot, or give it a good blast up the motorway and return to slow speeds in town, then I would expect a well functioning coolant system to creep up to around 95C, then the V6s have 2-stage fans, a lower speed which kicks in first at around 95C or so, and a higher speed which kicks in if it gets too toasty, I think somewhere around 100C, can't remember exactly.

When I bought my V6, the 2 stages worked perfectly, then at some point the lower speed stopped working and only the high speed worked, which I was pretty sure down to a faulty resistor bolted to the back of the fan unit.

The temperature gauge sender won't affect the fan as you said, but it sounds like it is due replacement anyway, if all the hoses get hot and the radiator gets hot then I'd assume there are no airlocks or jammed thermostat valve.