POSSIBLE CAUSES OF OVERHEATING
Overheating can be caused by anything that decreases the cooling system's ability to absorb, transport and dissipate heat: A low coolant level, a coolant leak (through internal or external leaks), poor heat conductivity inside the engine because of accumulated deposits in the water jackets, a defective thermostat that doesn't open, poor airflow through the radiator, a slipping fan clutch, an inoperative electric cooling fan, a collapsed lower radiator hose, an eroded or loose water pump impeller, or even a defective radiator cap.
One of nature's basic laws says that heat always flows from an area of higher temperature to an area of lesser temperature, never the other way around. The only way to cool hot metal, therefore, is to keep it in constant contact with a cooler liquid. And the only way to do that is to keep the coolant in constant circulation. As soon as the circulation stops, either because of a problem with the water pump, thermostat or loss of coolant, engine temperatures begin to rise and the engine starts to overheat.
The coolant also has to get rid of the heat it soaks up inside the engine. If the radiator is clogged with bugs and debris, or if its internal passages are blocked with sediment, rust or gunk, the cooling efficiency will be reduced and the engine will run hot. The same thing will happen if the cooling fan is not engaging or spinning fast enough to pull air through the radiator.
The thermostat must be doing its job to keep the engine's average temperature within the normal range so the engine does not overheat. If the thermostat fails to open, it will effectively block the flow of coolant and the engine will overheat.
Exhaust restrictions can also cause the engine to overheat. The exhaust carries a lot of heat away from the engine, so if the catalytic converter is restricted, or a pipe has been crimped or crushed, exhasut flow can be restrricted causing heat to build up inside the engine.
It's also possible that your engine really isn't overheating at all. Your temperature gauge or warning lamp might be coming on because of a faulty coolant sensor. Sometimes this can be caused by a low coolant level or air trapped under the sensor.
POSSIBLE CONSEQUENCES OF ENGINE OVERHEATING
If your engine is overheating, it may start to detonate. The engine may rattle and ping and lose power. If detonation continues, it may damage the rings, pistons and/or rod bearings.
Overheating can also cause pisto scuffing. As the engine gets hotter and hotter, the pistons may swell to the point where there is no more room for expansion and they scrape against the cylinders, damaging the pistons and cylinders.
Exhaust valves may also stick or scuff in their guides. This can damage the valves, guides and lead to a loss of compression.
Another consequence of engine overheating may be a blown head gasket. Heat makes aluminum swell almost three times faster than cast iron. Thermal stress can distort the head and make it swell in areas that are hottest like those between exhaust valves in adjoining cylinders, and areas that have restricted coolant flow like the narrow area that separates the cylinders. The typical aluminum head swells most in the middle, which can crush the head gasket if the head gets too hot. This will usually cause the head gasket to leak compression between adjacent cylinders, or leak coolant into the cylinders.
Engine overheating can also cause an overhead cam to seize and break.
Engine overheating may also stress old radiator and heater hoses and cause they to burst under the additional pressure. Steam that is generated inside the cooling system can also damage radiators with plastic end tanks.
A HOT warning lamp should never be ignored. Though a few high tech cars like Cadillacs with the Northstar engine can disable cylinders to "air-cool" the engine and keep it running at reduced power in the event of coolant loss, most engines will suffer serious damage if they overheat. So advise your customers to stop driving at the first sign of overheating. Turn the engine off, let it cool down and try to find and fix the cause before risking further travel.
Change your thermostat. Ensure that your radiator fan is running at idle. See if your heat blows warm or not when the engine is warmed. if the heat is clod, then you have no water circulation in your engine. either the thermostat isnt opening up, or there is a blockage in your cooling system.
SOURCE: Overheating '97 Ford Taurus
Make sure the thermostat is good. The water pump impeller is made of nylon or plastic on many of these engines and can brake inside the pump without giving the indication of a leak at the pump gasket or bearing. It happened to my girlfriends 97 taurus V6 DOHV. The engine was overheating and there was no heat coming from the blower when switched to hot air. This indicated that there was no coolant circulation. The mechanic replaced the bad water pump and thermostat and it has been fine since. Hope this helps. God bless
SOURCE: Brake fluid leaking from master cylinder Reservoir
solve the problem by replace or rebuild the master cylinder. This happens over time.
SOURCE: 99 hyundai elantra. I accidently left the cap off
Read this informative article that will tell you what to do to find out why the engine is overheating.
SOURCE: Engine heating up to overheating but no heat in
I need more info but are you saying that the anti-freeze is back flowing into the overflow
is it overflowing
ok for one it might be the thermostat
but my concern is the over flow
It can be a sign of a bad head gasket
the symptoms are overheating
anti-freeze back pressure
get back with me
hope it works
SOURCE: My car is overheating and
The entire cooling system should be diagnosed.
By this, I mean that the system should be checked for the possibility of blown head gaskets (especially if it has already overheated - good change of warped cylinder heads). The Engine Coolant Temperature (ECT) sensor needs to be verified to make sure it is working properly. This needs to be done with a scanner that can read sensor data. The actual temperature of the engine should be checked with a pyrometer or infrared thermometer while comparing the ECT data to see if it matches. The radiator cooling fans should be checked to see if they come on at the correct temperature (225 to 230 degrees Fahrenheit) - this also will require a scanner. If the fans are not working properly, then the fan circuits must be diagnosed.
The thermostat may also be malfunctioning...Please note that NEW and GOOD are NOT the same thing! It would not be the first time I found a NEW thermostat messing up. Again, proper thermostat operation can be verified by graphing the ECT data, or using an infrared thermometer to determine exactly when the thermostat is opening (if it is even bothering to open at all.)
Then there is the possibility of a damaged water pump that is not circulating the engine coolant properly. Also a clogged radiator is always a possibility on a 12-year-old car.
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Flushed heater core radiator and changed thermostat but same issue. Top hose gets hot as fire lower hose is cold
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