172 ph1 too much pressure in expansion tank after warm

[whiteryno111]

Hi, I bought a clio a few days ago and I'm sorting out little problems. The other day my mechanic noticed excessive pressure in the expansion tank, irregular idle and too much vapor out the exhaust. Head was off, new head gasket, new water pump, thermostat... all put back together and the problem still remains, the radiator was checked and it's flowing well... Any suggestions? All I can think of is warped head or a crack somewhere inside the head. When cold there's no pressure buildup in the coolant tank. Getting a bit frustrated as it's not easy or cheap to find these cyl head in Portugal.


Thanks guys
Cheers

 

[MicKPM]

Was the actual pressure measured? Has the cap been tested?

 

[whiteryno111]

It wasn't tested for actual pressure, but after it's warm you can't open the bottle cap because it overflows everytime even after the fan starts...
Temperature is quite normal and the fan starts a little after the middle of the temp indicator.

 

[MicKPM]

That's normal though and the cooling fans should kick in around 98-105°c IIRC on the X65 but that is in our UK "moderate" climate.

Is the heater blowing hot or cold air?

 

[Djw John]

Ouch. How much has it cost you so far? Cos it sounds like you're trying to fix a non existent fault.

 

[midge]

I bought a Fiesta once with a similar problem owner said the mechanic had told him it was head gasket failure. I fixed it, it was a faulty expansion tank cap.

 

[1958steveflying]

The reason the coolant system is under pressure is to raise the boiling point of the water from it's normal 100c. If the engine runs ok, comes up to temperature and the fans cut in then it should be left alone until the whole system is cold, then the coolant level should be checked. You are only likely to have a problem if it either throws out coolant during running or loses water when checked again at cold.

 

[TheEvilGiraffe]

Head was off, new head gasket, new water pump, thermostat...

Any suggestions?

Check the timing ?!

:quiet:

 

[whiteryno111]

The heater works just fine, I'll just buy a new cap and get a few miles on it then i'll check if the coolant level remains the same.
Whats puzzling is that normally there's a point after a car's engine is warm where you can remove the cap from the tank and the coolant doesn't come out, you just hear the air coming out and the coolant stays in the expansion tank, it's not the case here...

 

[Djw John]

What you are describing is 100% normal. Trust us. Please don't spend anymore.