Radiator Probelm

[Powerefx]

Hey guys ive got a problem or i think its a problem on my 93 ford escort. When the temp gauge reaches 3/4 of the way to hot, and this is in standing position, the water/coolant begins boiling. Is this normal, or should it not be boiling it this soon? What must i check to make sure it doest start boilingtoo soon?

[MagicRat]

Originally Posted by Powerefx

Hey guys ive got a problem or i think its a problem on my 93 ford escort. When the temp gauge reaches 3/4 of the way to hot, and this is in standing position, the water/coolant begins boiling. Is this normal, or should it not be boiling it this soon? What must i check to make sure it doest start boilingtoo soon?

Sometimes if the coolant is mostly or all water, it will boil too soon.
Your coolant should be 50/50 water and anti freeze for best protection.

Also if your radiator pressure cap does not hold pressure, it will boil over too soon. When your engine is up to operating temp, put a glove or oven mitt on it and give the upper radiator hose a good squeeze. It should feel hard, like an inflated bicycle tire. If you can almost squeeze the rad hose closed, likely your rad cap is malfunctioning. It might also be a leak in the top of the radiator
Finally, is your radiator fan working properly? If your car starts to boil over only when you are not moving, the fan may not be working.

[curtis73]

^^^ ditto.

[sracing]

Originally Posted by Powerefx

Hey guys ive got a problem or i think its a problem on my 93 ford escort. When the temp gauge reaches 3/4 of the way to hot, and this is in standing position, the water/coolant begins boiling. Is this normal, or should it not be boiling it this soon? What must i check to make sure it doest start boilingtoo soon?

At atmospheric pressure (cap open) it will boil at 212 deg f. Your engine should not run that hot normally in any case. However with the cap on and a closed system it will boil at more like 226 (14lb cap).

Jim
SR Racing

[MagicRat]

Originally Posted by sracing

At atmospheric pressure (cap open) it will boil at 212 deg f. Your engine should not run that hot normally in any case.

If I may suggest the following:

Virtually all liquid cooled engines run with 'hot spots' in the cooling system, these are areas, such as the cylinder wall or around the exhaust valve where there is some isolated boiling, with temperatures somewhat higher than 212. This is normal.
The pressure in a proper cooling system will prevent the isloated boiling from going too far, but without pressure, its easy for the boiling to go out of control without actually overheating the engine.

Also, water boils at 212 at sea level. If you are driving at higher altitudes, the cooling system will boil over at a lower temperature, if there is no pressure in the cooling system.

[SaabJohan]

With a typical system pressure, and a 50/50 mixed coolant, the coolant start boiling around 130 degC (266 degF). For a typical roadcar it's common to have a fully opened thermostat at 90 degC (194 degF), with electric fans staring to work at 100 degC (212 degF). The fans usually won't go at full speed until 110 degC (230 degF) or so.

Inside the engine block the pressure is somewhat higher since the waterpump is pumping in coolant while the termostat (or restrictors in some racing engines) is restricting the outflow. This means that the boilingpoint is higher in the engine which prevents local boiling. If the coolant starts to boil locally at areas with high temperatures you will soon have melted the metal in the area as watervapor won't cool the engine enough.

The first thing one should check if the engine gets too hot is if the fan is working, as I mentioned they usually start at 100 degC.