Driving your car with the temperature warning light on can add to the risk expensive engine damage! When the temperature light comes on, it implies your engine is overheating (running too hot). An engine should not overheat if the cooling system is normally filled and is working normally — even during hot weather or stop-and-go driving. Sometimes abnormal driving situations such
as towing a heavy trailer during hot weather may overload the cooling system’s capacity to control heat, but often a temperature warning light means trouble.
What To Do If Your Temperature Warning Light Comes On
STOP DRIVING IMMEDIATELY!. Pull over to the other side of the road as soon as it is safe to do so, then shut off your engine and allow for things to cool down.
WARNING:PLEASE Do NOT attempt to open the radiator cap! The radiator has hot water under high pressure. Opening the cap on the radiator or a pressurized coolant reservoir could make steam and water to blow out and burn you. There’s nothing to be gained by opening the cap while the engine is still hot, so let your car sit and cool off.
After things have completely cooled down (wait at least half an hour or more), then you can open the radiator cap or reservoir and inspect the coolant level. Put a rag over the cap first, and slowly turn the cap until it stops at the first detent. This should allow residual pressure to be released. Wait until all pressure has been released before removing the cap the rest of the way.
Put water or coolant to the radiator or coolant reservoir if it is low. Actually, you should add premixed coolant or a 50/50 mixture of antifreeze and water to sustain the proper freezing, boilover and corrosion protection. But in most situation when this happens, it’s an emergency situation and you won’t have a jug of antifreeze handy. If that’s the case, add water now, then drain out some of the coolant later and offset the extra water by including the proper amount of antifreeze.
Check for Coolant Leaks
Your engine may have overheated due to a coolant leak. Visually check the radiator, engine and cooling system for leaks. Common leak points include radiator and heater hoses, hose connections, the water pump and radiator. Internal leaks (such as a crack in the head or engine) can’t be seen and can only be diagnosed and fixed by pressure testing the cooling system.
IF YOU DON’T QUIT DRIVING…
If you continue driving an engine that is overheating, it can cause serious damage. The engine may start to knock (caused by detonation), which in turn can cause piston, ring and head gasket damage. As the internal parts of the engine expand from the excessive heat, clearances may be lowered to the point where metal-to-metal contact happens. Valve stems may gall and stick, and the pistons and camshaft might scuff or seize.
Severe engine overheating equally creates tremendous thermal stress in the head(s) and block. This, in turn, may result to cracking and/or warpage. This is a common issue with overhead cam engines that have aluminum heads.
The only car that can be “safely” driven when the temperature warning light is on a late model Cadillac with a Northstar V8 engine. Cadillac engineers designed the engine control system to automatically deactivate half of the engine’s cylinders if it senses an overheating issue. This reduces the heat (and power) being generated by the engine, and it lets the “dead” cylinders to pump air through the engine for internal cooling. The system is designed to offer a “limp-in” mode so the car can be driven to the nearest service facility or Cadillac dealer for repairs. It is not considered for continuous driving.