Coolant pressure

05-05-2003, 08:46 AM
Hi guys, Im writing from Italy to have from your experiences some informations about the coolant pressure. Since about 4 weeks the radiator of my car has a small liquid leakage from the bottom of the upper side of the radiator. This leakage starts only when coolant is hot and pressure is high. Then I changed the radiator cap (which works also as a pressure valve to the coolant reservoir) to make the pressure stay (even when hot) at atmospheric level. Now I have no leakage. Do you think it could be a problem for my cars engine? Haynes' manual says that the engine coolant system works under pressure to improve the efficiency and to improve the boiling point. Im not worried about the ebullition point because I have a coolant which boils at 125 C (257 F).
What about other possible problams caused by a non-pressurized coolant?
For now everything seems to be ok, even the coolant temperature at normal operating level(about 194 F).
What do you think?

05-06-2003, 10:57 AM
Replace or repair the radiator, it should not be used without pressure.

Local boiling can occur, this means that it can boil inside the engine where it's hot without the gauge say 125 C.

Your system will also leak, but now from the cap since it lets the watervapor out.

Coolant is also flammable, it should be used in a closed system.

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