Car overheating.

[AniaSM]

I have a Renault Megane but the engine temperature warning light keeps coming on. A friend has bled the water system for me and says the thermostat is ok.

When I run the car the engine overheats. If I check the engine then there's only steam in the pipes and the water in the bottle is lukewarm. Any idea what may be wrong ?

[Toureman]

You need to join this forum, I am sure they will help you with your problem.......

http://www.renaultforums.co.uk?referrer=599

[slave-plater]

im no expert, "but bleeding the system" , may not be the cure needed, to , eliminate thr red ligt , and stop the overheating problem... there maybe a blockage , but the problem may be larger , than you think , meaning a more labour intensive repair maybe needed , get the copression tested by a knowlegeable mechanic .....

[Cockney_si]

Sounds like there is a blockage in a hose from the radiator where the thermostat opens up.

I uesed to be able to do this.....Although water will be hot !

You would need to locate the thermostat on radiator hose and unbolt the hose and thermostat. put a bucket under the hole and start the car and wait until the car is at correct temperature to start circulating water out the hole. This could splutter out so be careful of hot water !

Then you can switch off the engine and bolt the thermostat and pipe back on and hopefully the system can then be topped up via the filler bottle.

[AniaSM]

I hope its not my cylinders head gasket. Im told this is an expensive repair.

[Whickerman]

was just going topost about the head gasket. Quick way to check is to open the oil lid and look for caramel colour sediment - a sure sign your head gasket's gone.

[chadad]

I had this trouble with a ford escort.
I had drained the system to renew the anti-freeze.
This caused exactly the same symptoms as you describe.
The problem turned out to be the the small hose that joins the thermostat housing to the expansion bottle.
This hose has the job of conducting excess ( expanded ) water into the bottle. It also allows air to escape from the system.
It turned out that this small hose was blocked with sediment.
The air couldn't bleed from the system so the water couldn't reach the thermostat and cause it to open.
Hose cleared, expansion tank filled, Problem solved.
Hope this helps. chadad