Car Over Heating And Cooling Really Randomly!

[sewelly]

Sat waiting for my mate today with engine running. Turned it off and for a minute and when i turned it back on it was full on the temperature gauge. so stopped again and then drove it back around the corner and it went back to half way like normal and then the gauge moved up and down a small bit. Any ideas why this might happen????

[Jesus]

Maybe duff thermostat.

Maybe air in your coolant system.

Maybe duff temp gauge/sender unit.

[Fletch2]

I had the same thing on my Lucida. Someone on the forum

suggested that it was an airlock in the cooling ststem, so I ran the engine with the cap off the header tank and ended up adding about three kettles of water.

Hey presto !! no more problems.

[sewelly]

cheers fellas thats what i thought to anymore suggestions? and when you run it with out the cap on do you add the water when the engines running???

[Bibbs]

yeah, just open the front rad, and add a clear hose ( tie the other end to the bonnet latch in the air, start the car with the rad cap off and then keep topping her up.

Don't add too much cold water in one go.

[GIDDLEPIN]

You'll find most cars will do it, no real big deal (unless you have a leak), the reason it does it is because when you shut down the engine the water stops circulating and the standing water temperature will increase, once you start the engine again you will see the needle dropping as the circulation returns.

[sewelly]

cheers fellas think its sorted now if not ill be back on tomorrow