My Car heat Goes Over 100 while driving over 120 KMH and i hear the fan running but the heat does no go down. when i slowdown the car the heat goes down so i changed :

1- waterpump (no result)

2- Head Gasket (no result) the mechanic said to me it was not bad

3- Thermostat (no result)

4- adjust valve cleance (no result)

5- tryed to drive without exhoust pipe to check if it was bloked (no result)

ps. the fan runs well all the time and do not cool the car while driving high speed and am not loosing the coolant

i am thinking to change the radiator can any boady help

the car made 134000 km without changing radiator

thanx...:(

Have you regularly drained and changed all the coolant?

If the coolant get stoo old or has too much addative in it it will start to boil all funny in the heat and then cause odd behaviour. For example too much antifreeze can cause the system to boil at an excessively low temperature.

thanx cheezemonkhai i finally changed the radiator and the coolant inside the radiator but the most strange thing the heat is still as is

Hmm have you tried the sender unit which detects the temperature and checked the guage just to make sure it isn't giving false readings?

I mean you have pretty much replaced the rest of the cooling system by the sounds of things.

the fan always runnig which means the liquid is hot

Or that the car 'thinks' the liquid is hot.

It might be that the sender unit that is measuring temperature is telling the car that the thing is hot even when it isn't. I guess teh easiest way to determine this is to see wether the pipes are hot, but I'm affriad i'm pretty stumped if it isn't this as you have pretty much changed the whole cooling system.

the fan switch is sepearate from the temp sender unit.... my quess is an air lock in the heater or the block somewhere..... try running the engine from cold without the cap on the expansion tank and top up as necessary. you should get all the bubbles up to the surface like this....

thanx it really worked ok you know i changed all the cooling system for that reson