8 Reasons Why Your Engine Coolant Temperature is High

25% of all engine failures are attributed to negligence in changing engine coolant. Similarly, 95% of radiators fail due to old or contaminated coolant. This simple yet effective mixture of glycol and water is an integral fluid used to cool any internal combustion engine. In this blog post, we’ll discuss the reasons why your engine coolant temperature can get higher than it should be.

Along with that, we’ll also cover the symptoms of engine coolant overheating and the normal temperature range.

So, without any further ado, let’s get started.

What is the Normal Engine Coolant Temperature Range?

Different car brands and engine types have different ranges of optimum coolant temperature. However, as a general rule of thumb, it should lie between 195 and 220 degrees Fahrenheit, or in Celsius, it should be between 90°C and 105°C. When your car’s coolant temperature is above 220°F (105°C), it is generally considered to be overheated.

Why High Engine Coolant Temperature is Bad for Your Car?

High engine coolant temperature can be detrimental to your car’s performance and longevity. When the coolant gets too hot, it can cause a variety of problems.

It includes pre-mature engine wear, reduced engine power, knocking or pinging (pre-mature combustion), increased fuel consumption, damaged pistons, a blown head gasket, and ultimately, engine failure.

Therefore, it is very important to keep an eye on the temperature of the engine coolant and take immediate action if it is over the specified limit in the owner’s manual.

8 Reasons Why Your Engine Coolant Temperature is Over the Normal Range

Here are the top 8 reasons why your coolant temperature is higher than normal:

1. Environmental Factors

The number one reason why your engine coolant might be running hot is simply due to the high ambient temperatures. This is especially true in hot climates or during heat waves.

There’s nothing you can do about it. You just need to avoid driving too much in this scenario. If you have to absolutely drive your car, make sure that the engine isn’t running for extended periods.

2. Low Coolant Levels and Coolant Leaks

Your coolant can become hot because there isn’t enough of it in the reservoir. The engine coolant can get lost due to evaporation or leaks. Coolant leaks due to a blown head gasket are pretty normal. When a small volume of coolant tries to remove engine heat, its temperature can rise very quickly, leading to an overheated engine.

3. Clogged Radiator or Hoses

Over time, debris, rust, and sediment can accumulate in the car’s radiator or hoses, obstructing the coolant flow. A clogged radiator or hose reduces the cooling system’s ability to dissipate heat, leading to increased engine coolant temperatures.

4. Faulty Radiator Fan or Cap

A radiator fan aids the engine cooling process by forcing airflow over the hot coolant. When the fan is broken, the heat dissipation from the engine coolant becomes slow.

Similarly, a radiator cap maintains the pressure inside the radiator. When it isn’t working properly, the pressure buildup inside the radiator can lead to higher engine coolant temperature.

5. Faulty Thermostat Valve

The thermostat regulates the flow of coolant to maintain the engine at the optimal operating temperature. If the thermostat is stuck closed, it prevents coolant from circulating, causing the engine to overheat.

Conversely, if it is stuck open, it may not allow the engine to reach the proper temperature. Both conditions can cause the coolant temperature to deviate from the normal range.

6. Water Pump Going Bad

The water pump is responsible for moving coolant from the radiator through the engine and back. This circulation is critical for absorbing heat generated by the engine and dissipating it through the radiator.

Any hindrance in the flow of engine coolant caused by a failing water pump can lead to a high coolant temperature and, in turn, a high engine temperature.

7. Excessive Engine Load 

Heavy acceleration, towing, or carrying excessive weight can place additional stress on the engine, causing it to work harder and generate more heat. This increased workload can push coolant temperatures above the normal range, especially if the cooling system is already compromised.

8. Blocked Exhaust

A blocked or restricted exhaust system can lead to increased back pressure, causing the engine to run hotter than normal. This can result from a clogged catalytic converter or exhaust pipe. If the exhaust gases cannot escape efficiently, it can lead to overheating and potential engine damage.

Why low engine coolant temperature is also bad?

It’s not only the hot coolant that is problematic, cold engine coolant poses risks of its own. Therefore, it is important that the coolant is maintained within the optimum temperature range. Here are the risks associated with too-cold engine coolant:

• Difficulty starting: Cold coolant will not allow the engine to reach a sufficient temperature. So, it may cause engine stalling or pose problems while starting the car.
• Engine damage: Low coolant temperatures can prevent engine oil from reaching its optimal viscosity, which is necessary for proper lubrication.
• Increased fuel consumption: When the engine runs cooler than optimal, it can cause the fuel to combust inefficiently, leading to increased fuel consumption.
• Increased emissions: During cold starts, engines operate with a rich air-fuel mixture, which leads to incomplete combustion and higher emissions of hydrocarbons (HC) and carbon monoxide (CO).

Frequently Asked Questions

How would you know if your engine coolant is running hot?

The engine temperature gauge in most modern cars is sufficient to tell if it is running hot. If the temperature needle moves into the red zone, it indicates that the coolant is running hot. As it can be a sign of many other causes of overheating, you might want to check for other things, like whether your radiator fan is always on or if the coolant is leaking.

Is it safe to drive with a high engine coolant temperature?

It’s generally safe to drive short distances with high engine coolant temperature. However, you should not ignore this issue for too long. Hot engine coolant can lead to a blown head gasket that will cost you up to £2,946 to repair or worse, it can leave you with permanent engine failure.

Wrapping Up: Should You Drive with High Engine Coolant Temperature?

No, while you can drive with high coolant temperature, you shouldn’t do so. Simply because you’re risking permanent engine damage by doing so. Maintaining the proper engine coolant temperature is essential for optimal engine performance and longevity.

It helps keep your car in good condition and enhances the resale value while selling your car. You can use our free car value calculator to see the most recent resale value of your car. However, if you notice any signs of overheating or coolant issues, it’s important to address them promptly.