Getting the “Engine Temperature too high, drive moderately” alert on your BMW is a pretty scary experience.
After all, you don’t want your engine to overheat and cause permanent damage to the motor.
So, what causes this message to pop up on your dashboard, and how do you fix it?
In this article, I am going to explain exactly that; let’s get into it!
BMW “Engine Temperature Too High” Meaning?
Now, let’s look at what this warning message really means on your BMW.
In simple terms, the “the engine temperature too high” alert is a warning that your BMW engine is getting too hot.
This means that your cooling system isn’t doing its job properly, and the engine is heating up faster than it can be cooled down again by outside air and coolant.
Your BMW is equipped with a special sensor known as an Engine temperature sensor or Coolant temperature sensor.
This sensor is located in the engine itself and monitors the temperature of your BMW’s coolant.
The ECT will trigger this warning message on your dashboard when it reaches a certain level.
BMW Overheating: Quick Fix Table
| Cause | Fix |
|---|---|
| Thermostat Stuck Closed | Replace the thermostat. The location varies with the BMW model. Refer to the owner’s manual or consult a mechanic. |
| Bad Electric Water Pump | Check the water pump. If malfunctioning, get it replaced by a professional Bimmer mechanic or BMW dealership. |
| Malfunctioning Coolant Temperature Sensor(s) | If actual engine temperature is correct, replace the coolant temperature sensor. |
| Low Coolant Level | Turn off the engine, let it cool, and check the coolant level. Top off with distilled water and anti-freeze as needed. |
What Causes BMW Engine Temperature Too High Warning?
Now, let’s go into more detail about what causes the BMW Engine Temperature Too High warning to pop up on your dashboard.
This warning light can be triggered by a number of different issues, but based on my experience from working on BMWs over the years,
Here are the most common causes of this warning:
1. Thermostat Stuck Closed:
The most common cause of this warning is a thermostat that is stuck closed.
The thermostat on your Beamer is responsible for controlling the temperature of your engine by opening and closing a bypass valve to regulate coolant flow.
If the thermostat sticks closed (or is faulty), it prevents coolant from flowing through your engine, which can cause overheating.
When the temperature reaches a certain point the PCM will pick up on this and display the engine temperature too high alert.
2. Bad Electric Water Pump:
Your Bimmer is equipped with electric water pumps, which are responsible for circulating coolant through your engine and radiator.
If your electric pump fails, the engine will overheat because it cannot circulate coolant effectively.
Based on personal experience as an auto technician, water pump failure is pretty common when it comes to BMWs,
I would say that after the thermostat, the water pump is the most common cause of high engine temperatures in BMW vehicles.
3. Malfunctioning Coolant Temperature Sensor(s):
Your BMW has a temperature sensor that tracks the coolant temperature. This sensor relays data to the car’s computer, providing details on engine heat.
With accurate temperature data, the computer can correctly gauge engine overheating risk. But if the sensor fails, the computer lacks precise temperature information.
It may then mistakenly conclude the engine is overheating, even when temperatures are normal. In short, the sensor allows the computer to make informed overheating assessments. Without accurate sensor data, overheating determinations become unreliable.
4. Low Coolant Level:
The fourth and final common cause of the “Engine temperature too high” warning on your BMW is a low coolant level.
If your BMW’s reservoir is empty or nearly so, it will not be able to circulate enough coolant through the engine to keep it at its normal operating temperature.
As a result, your car will display this warning. Fortunately, checking the coolant level is very simple.
How to Fix and Reset Engine Temperature Too High Warning on BMW
Lastly, let’s look at what you should do when you get a hot engine temp warning on your BMW.
1. Turn off the Engine and Check the Coolant Level
I recommend that you first turn off your engine and let it cool down.
Then, check the coolant level in your BMW’s reservoir to see if it needs to be topped off.
If so, add some distilled water and anti-freeze until it reaches the appropriate level (between min and max).
2. Replace the Coolant Temp Sensor
If the actual engine temp is correct, but the “engine temperature too hot” warning message is still appearing,
then it could be that the coolant temperature sensor needs replacing.
3. Check the Thermostat
If the coolant level is fine and you are still getting the engine overheating alert,
It’s likely that your thermostat needs to be replaced (since Bayerische Motoren Werke vehicles use a plastic thermostat)
The location of the thermostat will vary depending on the model; for example, a 3-series thermo location will be different than a 5-series and X3.
If you’re not sure where the thermostat is located, check your owner’s manual or ask a professional mechanic to help you out with this task.
4. Get the Water Pump Checked
If the thermostat is fine and working as it should, then the next thing you should check is the water pump.
I personally recommend that you get the water pump checked by a professional Bimmer mechanic or BMW dealership.
If they find that it’s not working properly, they can replace it for you,
If it is working properly, they will diagnose t the problem and let you know what is wrong with your car.
Additional Sources
https://www.repairsmith.com/i/blog/coolant-temperature-sensor/
https://bimmers.com/blog/bmw-electric-water-pump-issues-explained/