Leaking radiators cause overheating

By Jean-Marie Nsambu

IT was late in the night. But, the thermometer’s pointer of the double-cabin’s dashboard was reading red. It was barely a mile since Stephen Ofumbi had last poured water in the radiator, but the temperature steadily rose to 120o anyway.
He yet again had to pour in water or risked burning the gaskets and oil seals. Besides, he would feel the vehicle losing power, he notes. “But, a man gave me some jua kali tip, to pour in water mixed with curry powder.”
The trick seemed to work as the curry bubbled to fill the holes temporarily, Ofumbi testifies. “I managed to drive from Jinja to Kampala, without the engine overheating.”
In Kampala, he eventually had to take the radiator for repair. Perhaps, Ofumbi would not have experienced that inconvenience, had he been checking his radiator regularly.
Radiators vary. They are made of several different materials like aluminium, plastic, copper or brass. According to expert mechanics, a radiator repair can often cost less than replacement and even extend its span.
However, a faulty radiator is likely to cause significant damage to the engine. Among the effects is overheating of engine, which is often a result of a leaking radiator; coolant loss or a low coolant level.
An American expert, Larry Carley, at CarleySoftware.com, reveals that a weak radiator cap may also cause overheating. A cap may leak pressure and allow the coolant to escape from the system.
Other faults include a broken fan belt that fails to regulate the heated water or coolant or an electric cooling fan that fails to come on due to a damaged thermostat, relay, wiring or motor.
“Less obvious causes of overheating may include a clogged radiator filled with sediment as a result of coolant neglect, corrosion or using excessively hard water,” Carley warns.
“Incorrect ignition timing and/or a lean fuel mixture (which may be due to air leaks, low fuel pressure, etc.) can also elevate normal operating temperatures. An exhaust restriction (typically a clogged catalytic converter) can also make the engine work harder and hotter.” Carley says that too much heat in an engine can as well cause serious problems. Heat causes metal to expand! “Excessive heat can also cause cylinder heads to swell, warp and/or crack.”
When a radiator loses coolant, it is advisable that one looks out for leakages. But, it may be due to a defective radiator cap, or a distorted filter neck. If the hoses are intact, there may be a fault in the water pump seal or the gasket.
At times the cylinder head bolt torque may be improper. Evidence of this is a milky sludge in the oil. However, the problem would be with the gaskets in the cylinder head, leaking cylinder head or core plug; a leaking heater core or heater water valve; or the thermostat may have gotten stuck in closed position. Detonation is another occurence that can lead to devastating effects of the engine. It is a form of abnormal combustion that results from too much heat and pressure in the combustion chamber.
Says Carley, “The fuel ignites spontaneously causing a sudden rise in cylinder pressure. The result is a sharp hammer-like blow on the piston that produces a metallic knocking or pinging noise.”
“Light detonation is considered normal and should not cause any damage, but heavy or prolonged detonation can crack rings, pound out piston ring grooves, punch holes through the tops of pistons, smash rod bearings and blow head gaskets.”
Experts recommend that it is important to take note of the vehicle’s response before driving off for the new day and when packing at the end of the day.
Checking the radiator pressure cap is a recommended system to find out the pressure level and the thermostat for proper opening and closing.
Pressure tests to identify any external leaks to the cooling system parts are also recommended. These parts include the radiator, water pump, engine coolant passages, radiator and heater hoses or heater core.