Engine temp

[andyj941]

How hot does the thermostat housing and engine get on a 1.3 fiesta in degrees C? Just sealing housing as still leaking

 

[Stivino]

It'll be at least as hot at the temp that's stamped on the thermostat or the box it came in. So if it opens at say 98°C then it'll get as high as that and maybe even higher.

 

[TicklyT]

Cooling systems are pressurised to increase the boiling point of the coolant, so the temperature could easily exceed 100 degrees centigrade.

IIRC a radiator cap incorporating a 13 PSI pressure relief valve will not allow the system to boil until the temperature reaches about 125 C.

That's what makes releasing the radiator cap on a hot engine dangerous - once the pressure is released, the coolant, which may be above it's boiling point at atmospheric pressure instantly boils, blowing hot coolant out over anything (and anyone) in it's way.