Heater/thermostat Problem

[GTE999]

Guys, yet another problem.

If im driving in normal traffic ie through the town, my heater is fine and provides warm ayr, however staying in Ayrshire in Scotland i do a lot of motorway driving and as soon as i pick up speed the temp gauge goes to the blue and its cold air that comes through. Any ideas??????

Think it maybe something to do with the thermostat but am unsure!!

[Iain]

I have a similar problem, and have found that my coolant system is not pressurising very well. Is yours?

I'm also thinking thermostat so am going to change that and take it from there.

[GTE999]

To be honest mate, im not sure if its pressurising ok (how do i check)? I was thinking of changing the thermostat aswell. At first it didnt bother me that much but now were in the winter its a bit of a problem!

[Iain]

You can feel the large coolant hoses when the engine's warm (or as warm as it'll get) and check if they feel hot and under pressure. You can also (slowly!) unscrew the header tank cap and see if it hisses, if it does it's pressurised.

However it might be completely unrelated and I'm wasting your time lol

[GTE999]

Not at all mate, i appreciate any help i can get. I'll certainly try that and let you know.

btw, ive heard some folk use cold running thermostats whatever that is. Any idea? Just wondering in case mine has one!!

[Welsh Dan]

It does sound like the thermostat is stuck open. Leave the car idling at standstill for 20 mins or so, squeeze the big hoses and they should feel hot+firm, if they do then the system is pressurising, and its only likely to be the thermostat at fault.

[GTE999]

Ill try that and see what happens. btw any idea what a cool running thermostat is?

[Welsh Dan]

A cool running thermostat opens at a lower temperature, allowing coolant to pass through the radiator.

[Adam]

And is not neccessary

[mikey14sr]

I take it the air temp up your way is quite low? Does the gauge move up and down a bit once it's dropped into the blue?

If it does rise and fall a little, chances are the thermostat is fine, and it's just the cold air going through the rad that's dropping the temp to the point at which the 'stat starts to close, then it opens again as the coolant behind it gets back up to it opening temp.

If thats the case block off half of the rad with a piece of cardboard on the front side (between the bumper and the rad), this'll reduce the effective size of the rad and keep the coolant warmer.
Don't do it if you spend a lot of time sat in heavy traffic though, as when the fan comes on it won't be sucking any air through the rad and the temp will go into the red, and possibly go bang!

[Welsh Dan]

Just block the side that the fan doesnt use.

[silvertornado_sr]

i had same problem with my escort as i said to iainel the other nightstanding around is fine but as soon as ya hit 60 road temp goes down to cold and mine didn't even have a thermo in it so put one in and now is fine :D

thermo ya problem can probs put money on it:thumb:

[GTE999]

cheers guys.

[Iain]

Just to let you know I replaced my thermostat and it has cured my cold running problems. Hope you get yours sorted soon GTE999. :)

[GTE999]

Changed my thermostat which was a pain in the backside and now i have hot air!!

Thanks for the help guys.