Peugeot Forums banner

307 sw Boiling the coolant

5K views 4 replies 5 participants last post by  storeman 
#1 ·
Greetings to all

I have a little problem with my Pug 307 HDI sw 1.6 16v, year 2005.

The car is all fine while driving out of city traffic. However once in the city and in heavy traffic, and driving up the hill the engine temperature rises up to approximately 100'C - and that's when the fan kicks in. In case I stop (engine off) the car - when the temp. is around 100'C - and go about my business the coolant in the tank boils and leaves through the expansion bottle.

I took the car to mechanic and he first changed the thermostat, and then one of the sensors - the one just behind the front bumper. However, the car still boils the coolant. Don't know what steps to take now. Any suggestions or possible solutions?

Previously the car temp. would not rise up to 100'C, it would stay at 90'C.
 
#2 ·
Does the tank pressurise?
If it doesn't it will cause the coolant to boil, 100 deg is after all the boiling point and the pressure in the system should stop it happening until it's a fair bit hotter.
Worth checking that the cap seals when it's warm and that it gets hot through the heater as well as the water pipes and top/bottom of radiator.
Obviously release the cap carefully!
90 deg is about right so if the water goes through the radiator and the fan kicks in it should cool.
A new radiator may be worth a replacement as they do block and are not to pricey or hard to change but check the water pump actually moves the water around.
Let us know how it goes
Mark
 
#4 ·
Check to see if the whole radiator get hot once thermostat opens. If no possible blocked radiator core.

Does the heater get fully hot and if you blip the throttle with cool engine and the cap of the expansion bottle does the water level drop a small amount -If no maybe impeller has fallen off water pump
 
#5 ·
Boiling at 100 degrees indicates the system isn't pressurising so I'd suspect the expansion tank cap needs rep[lacing as previously suggested. It's definitely the cheapest of the options already suggested and by far the easiest to try. Cooling systems are pressurised to increase the boiling point of the coolant so the liquid shouldn't start boiling until it reaches around 120 degrees.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top