Why Your Car Overheats When Idling & What To Do About It

 

5. Coolant Level

As you can imagine, the internal combustion engine makes a lot of heat. That's why they're equipped with cooling systems that circulate liquid coolant and keep the metal engine at a safe temperature. If the coolant level is low, expired, or the wrong type, you may have overheating problems in your vehicle. Keep up with recommended maintenance at an authorized dealership and check the coolant level regularly. Most modern cars have a coolant container that you can simply look at to determine the coolant level. Remember, never remove the radiator cap on a vehicle that has recently been running. If you're not sure, give the radiator hose a squeeze. If it has pressure in it, don't remove the radiator cap.

 

4. The Coolant May Have Leaked Out

Typically, this is something that you'll notice since there's likely to be a significant puddle under your vehicle. Over time, the seams on a radiator get old, hoses don't get replaced when they should, freeze plugs let go, and important maintenance services get overlooked. Often, the result is a coolant leak. The best way to avoid this cause of an overheating car is to keep up with recommended maintenance at and authorized service center like ours at Capitol Toyota.

3. Poor Airflow

The radiator is where hot coolant goes to lose a lot of the heat it picked up in the engine, and airflow is an important part of cooling the fluid inside the radiator. When you're driving along, air will flow over the radiator just behind the vehicle's grille. However, when you stop, get stuck in traffic, or something like a plastic bag prevents air from flowing over the radiator, electric fans will kick on in a modern car to maintain airflow over the radiator. If there's a problem with these fans or the switch that automatically kicks them on, you'll notice the vehicle overheating when stopped or otherwise idling.

 

2. The Car May Need A New Thermostat

The cooling system for your car's engine is equipped with at least one thermostat. This is a valve inside the system that will prevent the circulation of coolant until a certain temperature on the engine side of the system is reached. Once the coolant around the engine reaches this temperature, the thermostat opens to allow the hot antifreeze to go to the radiator and the coolant that's been sitting in the radiator into the engine. If the thermostat isn't opening and closing when it should, the engine could overheat.

1. Is The Water Pump Doing Its Job?

If the water pump in your engine isn't doing its job, you'll likely notice the car overheating when idling or headed down the road. The water pump does just what you would expect by pumping coolant through the system. This pump is typically belt-driven, so giving the engine some gas may temporarily improve the cooling only for the temperature to rise when the engine returns to idle. Replacing a car's water pump is a big job, and we recommend leaving this overheating diagnosis and repair to the experts.