Over heating

[wargriff]

When driving my temp is fine, when I slow down my temp goes up to red. Then couple seconds later returns to normal. This has happened a few times. The fans are working and coolant levels are good.

Any idea why it would suddenly get so hot and then normal and then hot again ?

All help appreciated.

Marc

[Hoover.]

otter switch acting up ??????

[rigga]

I would think the otter switch either works or it dont,once they fail thats it,so id say an air lock,but then the coolant level is ok with no leaks,so thats not helpfull either......

[spend]

Bad connection on the temp sensor?

[TV8]

I had a similar experience with the odd boiling over. It was a loose cap! At the risk of tempting fate.....its been fine since

[daveb500]

Could this behaviour be caused by an airlock in the system?

[wargriff]

Have checked all levels and all is fine. Have replaced otter switch.
Seems ok for moment.

Thanks for help

[yellowgriff]

I know this sounds strange but is it really boiling. When the car gets that hot open bonnet 7 check top & bottom hose coming from rad, One should be a lot cooler than the other,
It could be quite a few things. one of which could be the thermastat sticking closed. starting with this is a cheap fix, As we all well know this needs to be fixed pretty quick before it does headgaskets & all sorts''
Making sure both fans are cutting in & out at right time.. Semi blocked radiator. relay switch, most thing here are quiet easy fixes,
It you bypass the fan switch with a lump of old wire go for a drive leaving the fan running all the time this will eliminate the blocked rad & thermastat sticking. Hope this might help.Goldie