Engine overheating for any reason is serious and can cause irreparable damage, as you know, especially if it was one of those cheap engines found in the marketplace. If you have a customer whose car is constantly overheating and they haven’t figured out why, there are a few common causes that you can check for. These range from the obvious to the not so obvious, but the following list will help you troubleshoot the situation and get your customer back on the road.

1. Low Coolant

This is an obvious one, but check the coolant first. If it’s low, then the engine will certainly overheat. Low coolant isn’t necessarily the underlying root problem, and it can be just a symptom of a larger condition. However, start by filling up the radiator and coolant reservoir and then go from there.

2. Thermostat

One of the more common causes of overheating is a stuck thermostat. If the thermostat won’t open, then the coolant can’t cycle through the entire system. Conversely, if the thermostat won’t close, you’ll see other issues, though overheating isn’t one of them.

3. Leaks in the System

If you notice that the coolant is low, the first step after topping it off should be to check for coolant leaks. These can range from minor pinhole leaks that are very difficult to spot to major leaks that cause immediate puddles on the floor (the customer should have noticed puddles of coolant, but never put it past them not to see them).

4. Cooling Fan Problems

Engine coolant alone can’t handle the heat generated by engine operation. The cooling fan (or fans) on the vehicle also play a role here. There are two primary problems that crop up with cooling fans. The fan clutch could be failing, or there could be a faulty fan motor. Both of these are easy fixes.

5. Water Pump

The vehicle’s water pump is responsible for moving coolant throughout the system. If it’s failing or leaking, it needs to be replaced. This is usually not as simple as it sounds, as most water pumps are difficult to get to and will require that you have the car on a lift, and at least one wheel off so you can get to the pump.

6. Faulty Radiator

If the radiator is clogged with debris or buildup, this will reduce the cooling system’s efficiency and lead to overheating. Check for damaged fins and buildup within the radiator (including oil buildup, which can indicate a blown head gasket).

These are some of the more common problems that cause engine overheating, though there are many others. Start here and work your way through the list.