Hello,
Please I'd like to know if the presence of air trapped in a car's cooling system can cause the thermostat not to function.
I use a 2005 Peugeot 307 and recently I've been experiencing overheating and when I check I notice that the pipes from the radiator are very stiff and I can't press them which is a sign of air in the system then I notice that the radiator is also cold together with the upper pipe connected to it. This indicates that the thermostat is not opening when needed. Then I take the car to a mechanic to bleed it and I get some improvement and I could use the car for a day or two or some hours then it overheats again and the radiator stays cold while the expansion tank will be filled almost to the top with coolant without bubbling and sometimes the coolant is also cold .
Please what could be the problem?
I'm tired of bleeding regularly.
And where could the air be coming from?
First, find a better mechanic. A competent mechanic should be diagnosing this problem with some straightforward and inexpensive tests, not "bleeding" the cooling system. Three things are likely the cause of your symptoms - a blown head gasket, a stuck thermostat and/or a malfunctioning coolant pump. A compression check can tell you if you have a blown head gasket, a stuck thermostat can be tested by removing it and putting it in boiling water - check those first. The coolant (water) pump will leak or not rotate smoothly. There are Youtube videos on how to do these tests.
