Help! my Volvo has just started over-heating!

[morrisoff]

In the last couple of days the temperature needle on my Volvo 440 keeps running up to the high mark (particularly when I'm idling) and I'm having to put the heater and all the blowers on full to bring it back down again. Any ideas what's causing it? I'm not losing water from anywhere.

[morrisoff]

No, come to think of it, I haven't heard the fan come on for a while.

[morrisoff]

Since I last posted I took the car to a garage and had the thermostat replaced and the fan sender switch checked and cleaned - the car is still running hot! I've checked the hoses from the radiator as asked and they are warm. Yesterday I put some radiator sealer in the radiator, just in case there's a leak, but that doesn't seem to have made any difference yet. What else could it be?

[morrisoff]

Well it's not the gauge, i'm not loosing coolant and in desperation i've taken the car back into garage today to take another look at the fan sender -
they're gonna replace it when they can get the right part (wrong part arrived this afternoon). Let's hope that'll fix it!

[morrisoff]

It wasn't the fan sender unit. Garage called this morning to say it needs new head gasket and shims. Looks like I'm in for a big bill!

Thanks to those people that replied to my post anyway.