306 XSi too hot after fixing misfire problem

not wanting to ask the obvious but is the electric cooling fan cutting in when it should, Only ask this as I had a Vauxhall many moons ago and if you watched the temperature gauge then as soon as you saw it pass a certain point you new the fan would cut in, plus it had a battery gauge so you could see the power drain. Occasionally the fan would not cut in and it was usually a dirty connections, once it was the relay that had failed Anyway, its a fine line between the fan coming on and the engine overheating.

GGJ

AFAIK the fan is cutting in - at least it's can hear it running for a few minutes when I switch the engine off!

I'll see if I can hear it cutting in in normal operation.

Thanks for your thoughts.

jon

It hasn't got two fans has it and only one working? Seems to be quite a common Pug problem to do with relays.

Hi Keith

Some more experiments: I unclipped the connector from the radiator thermostatic switch and shorted it; the fan started up fine. And it runs for a few minutes after the engine has stopped. I've heard it running whilst driving but haven't determined at what temperature it cuts in.

I've just driven around 5miles/10 minutes (A roads mostly) from 'almost cold'. The temperature gauge has just hit 110. From feeling around the radiator, the Right Hand Side (looking from the front) of the radiator, including the hose, is pretty hot. The middle and LHS of the radiator are cool.

I'm wondering if the thermostat is b*ggered?

Cheers jon N

Does sound as if it is stuck in the closed position or not opening early enough. I only know one way to test that. It involves removing it, a cooker, a large saucepan and a cooks thermometer. The rest you can probably work out for yourself. On my old Princess (the last time I had occasion to test one) it was supposed to open as the water approached boiling, bearing in mind it boils at a lower temperature than in the car because it is not pressurised.

If the 306 is anything like the 406 watch out on refilling. On the 406, because the water circulates higher than the filler cap, you have to artificially raise the filling position. I believe plastic lemonade bottles with their bottoms removed can be used provided that a good seal is maintained where it enters the filler neck. You could, of course, also stand the car on its tail ;o)

sounds like your thermostat is stuck closed as suggested. You could test it using boiling water in a sauce pan , but to be honest I would just replace it with a new one. It could also be well worth it while you have the radiator pipes off to blast a hose pipe through it from on side to the other and see if any crud comes out of it, could find that half of the radiator is blocked with crud . Best of luck, let us all know how you get on. GGJ

Hi Guys Thanks for the suggestions. I'm trying to locate a new thermostat at the moment. Unfortunately the one for the 2L XSi seems to be hard to come by ...

I had a look at the thermostat housing. On this model at least, on top of the housing there's a small unscrewable knob, very like the top of a toothpaste tube (though black plastic obviously). Any clues what this is for?

Cheers Jon N

Bleeding the cooling system

Hi Bob

Thanks - I was guessing this might be so, & now I've found the right pages in the Haynes manual ;-)

I'm actually wondering if the problem has been an airlock in the cooling system all along. Things have been significantly better after I loosened and refitted the small 'toothpaste' knob. I also note that the hose from the thermostat gets 'properly hot', indicating I think that the thermostat is operating.

Anyway, since a new thermostat is only 12 quid or so, I think I'll get one and drain & flush the whole system anyway. I'll let you know how I get on.

Cheers jon N

If your in the u.k dont forget the anti freeze.you might think i do it later but you always forget and by then its too late.