Water Reservoir Tank Boiling

Federal mogul radiator cap.

Water reservoir tank boiling.

Do not remove a radiator cap from a hot engine to check. You can experience a shot of boiling water exploding under pressure. That would indicate a blown headgasket. The increase in pressure will also increase the boiling point of the coolant.

Here is a handy chart if you ever need it. It means there is air in your cooling system and this is always a bad thing. When the coolant is released to the reservoir it may boil because of the fact that it is at atmospheric pressure and the water portion will boil at 212. The reason a bad cap can allow the water to boil is because the pressure the cap is designed to keep in the cooling system makes it more difficult for the water molecules to escape as a gas.

The engine cooling system is pressurized somewhere between 5 to 15 pounds per square inch. It has some other useful tools and info in it. Https invol co clo1ds in this video i ll show you how i was ableto fix the issue i had with the reservoir of my honda civic 1999. In fact if you placed the coolant in a vacuum it would boil sooner.

I suspect that the boiling you were seeing in the reservoir wasn t boiling at all but was actually combustion gasses being blown into the water jacket and migrating out to the reservoir where they were coming out as bubbles. One of the most common causes is a blown head gasket in which the air pressure inside the cylinder heads is transferred to the cooling system. It could mean that air is somehow getting into an otherwise pressurized liquid system or it could mean that the the last time the coolant was changed some air was. This escaped air causes bubbling in the coolant antifreeze reservoir which can often be mistaken for boiling.

The fact that the coolant was boiling out of the reservoir cap suggests that the thermostat may be stuck closed.