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By YOUCANIC on Dec 19, 2018

How to check BMW Coolant Level - Low Warning

Is your BMW Low Coolant Level Warning on? Checking the coolant level on a BMW is easy and takes less than five minutes. It is crucial to follow the correct procedure to avoid injuries and get an accurate reading.

Ideally, you should use Genuine BMW Coolant or an acceptable BMW coolant alternative. Before you can safely check BMW coolant level, you need to wait for the engine to cool down. Here you will find instructions to check the engine coolant level and add coolant to any BMW. 


bmw coolant level low warning

Older BMWs had a translucent coolant reservoir with a line that shows the high and low level. Back then it wasn't necessary to remove the cap to get a coolant reading. BMW redesigned the cooling system, and now they use an expansion tank. Instead of the transparent tank, they implementing the float design ( the rod that pops up). 

Symptoms of BMW low coolant level

  • Engine coolant level light on
  • Message on iDrive stating Low engine coolant level
  • Engine Overheats
  • Coolant warning on, then off after driving
  • Engine coolant level too low
    • Risk of engine damage! Top up the coolant at the earliest opportunity, See owner's handbook. Caution: Risk of scalding!

How to check BMW Coolant Level

Follow these easy steps to check the coolant level on any BMW. Make sure engine is cooled down before you remove the cap from your coolant reservoir or you risk getting burned. There are no special tools needed to top off BMW cooling system.

Always check BMW coolant level when the engine is cold. Not only due to safety reasons, but also so that you get an accurate reading. 

Park BMW

Park your BMW on a level surface. Engage the parking brakes and move the shifter in Park. Allow your BMW engine to cool down. At least 30 minutes. Preferably more. If you decide to open the cooling system right after you turn off the engine, you need to be extremely cautious to avoid getting burned. 

bmw check coolant level

Open Hood

Once your BMW engine has cooled down, open the hood. Pull the hood release under the dash. 

Locate the coolant reservoir

As you open the hood, look at the left of the engine bay. This is the typical coolant expansion reservoir location. Some BMW models such as 3-series have the coolant expansion reservoir on the right side of the engine bay.

Remove the coolant reservoir cap

Turing it slowly will allow residual pressure to release without blowing off the cap. 

bmw check coolant level message


Determine the coolant fluid level

There are two different float designs.

  • The red float may have two balls. One indicating the low and the second indicating the full level. 
  • Red float may not have two balls.The level is full when the bottom of the float reaches flush with the top of the cap. 

how to check coolant level in bmw 1 3 5 6 series z4 e46 e39 x1 x5


If the float is all the way down you need to add coolant. If the float is sticking up your BMW coolant level is full. In other words, BMW coolant level is correct if the red float is aligned with the top edge of the filler opening. There is a schematic diagram stamped on top of the coolant reservoir illustrating the min and max level. Rember the level reading should be performed on a cooled down the engine for proper measurement.

If you see any seepage or coolant leakage around the cap you may keep getting the low coolant level. The cap may not be holding the pressure and could be leaking coolant. Replace the cap. Also, clean the cap as there can be a buildup of solids not allowing the rubber to seal the system and cause a leak. 

Typically to top off the system you don't need to add more than one quart/litter. To make the float move from the minimum level to maxim you need less than a quart of coolant. If you have to add more than one quart, you may have a coolant leak. If you are constantly adding coolant to your BMW or have to add more than one gallon of antifreeze, you may have a major coolant leak or a serious engine problem such as a blown head gasket

BMW uses a closed pressurized coolant system with an expansion tank. It operates differently than most coolant systems which have an overflow reservoir.

How to add BMW engine coolant

Always check BMW coolant level when the car is cold, and the engine is turned off. The coolant system pressurizes and if you remove the cap right after the engine has been running it will still be hot. The hot coolant will cause injuries. To avoid getting burned let the engine cool down at least thirty minutes. If you are stuck on the side of the road and you have no choice but to have to add coolant, make sure to remove the expansion cap very slowly. Keep your face and body as far away s you can.

What you will need


  1. Perform steps described above to check BMW coolant level. If you determine, the coolant level is low move to the next step. 
  2. Add engine coolant until the float moves up. 
  3. Start the engine. Set your heat to max and blower fan on. Let it idle for one minute. Next, rev up the engine to 1500-200 RPMs for about 30 seconds then turn the engine off. 
  4. Allow the car to cool down then recheck the level.
  5. If the level drops, add BMW coolant as necessary. Do not overfill the system. 
  6. Reinstall the cap. Tighten the cap until you hear a click. 

By allowing the BMW to idle and setting the heat on it allows the air pockets in the cooling system to escape. If you suspect air pocket in the engine and used this method, recheck the coolant level with the engine off. This will ensure you didn't overfill the system. 

If your BMW is under warranty, take your car to the dealer and they will top off the cooling system free of charge.

What BMW Coolant should I use? 

Not all aftermarket coolant are compatible with BMW cars. BMW recommends that you use their approved coolant. If that is not available there are a few coolant/antifreeze brands that are compatible with BMW cars.

BMW Coolant Alternatives

Regardless of the coolant brand you use including OEM BMW Coolant, always pre-mix it at 50% coolant and 50% water. Full strength coolant is not mixed and you will need to mix it yourself before adding it to the cooling system. Use distilled water instead of tap water. Tap water will work, but it is not recommended because it can introduce impurities, minerals and also cause corrosion to the cooling system over time.

You do not need any extra additives. The 50/50 mixture ratio can be used year round. 

BMW Coolant level full still get warning light

bmw coolant level warning on idrive message navigation

It is possible to still get a Coolant Level too Low warning even if you add coolant. The first thing that you need to inspect is the coolant level sensor if your BMW has one. It is possible that there may be an electrical issue with the sensor causing it to trigger the warning message. 

If you are extremely low in coolant, you may get the low coolant warning light even if you add coolant. The car was either neglected or was extremely low in coolant. Run the car for one minute and recheck the coolant level. It is possible that you need to add more coolant. 

Is BMW coolant warning message on, even though the coolant level is correct? This may be caused by outside temperature fluctuations or when using certain incompatible aftermarket coolant brands. Other possibilities include defective water pump, bad engine temperature sensor or bad coolant level sensor. 

Should I drive my BMW with coolant warning light on? 

Coolant and oil are two of the most critical fluid in your BMW. Driving without those can cause serious engine problems. The issue with coolant system is that even if the coolant level is full, it may throw the warning message due to a defective sensor. Despite everything else still working correctly. 

If that is the case, monitor the temperature gauge.  If your BMW has not been overheating or running too hot, it may be ok to drive the car. If the temperature gets above normal or you get a warning light that engine is overheating, stop driving your BMW. Get it towed to a mechanic ASAP. 

Frequently Asked Questions

It is possible that the coolant level is extremely low causing the float to be much lower than the min. In this case, it may be hard to see the float. Use a flashlight to look inside the coolant reservoir.

If the float device is not present it may been removed or broken.

No. Low coolant level warning should not turn on service engine soon or check engine light. Unless the coolant system is almost empty in which case the engine temperature sensor may malfunction triggering the check engine light.

If you overfill the cooling system, it may cause it to be overpressurized. Excessive coolant will be released via the release valve on the cap.

Most BMW cars, including 1-series, 3-series, 5-series, X1, X3, X5 use blue coolant.

Yes, but its not recommended. With that said, it is better to have some coolant than driving a BMW with no coolant at all. Once you get your car to a mechanic, you may want to do a full system flush and install the correct BMW coolant.

If BMW coolant too low warning light comes on and then turns off the level may have dropped slightly. Check coolant level and add as necessary.


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When you have a BMW coolant leak you will notice a distinct sweet smell that wasn't there before. You may smell coolant in the cabin. Or you may smell the coolant leak when the car is parked. After driving the BMW for a few minutes, open the hood and inspect for coolant leak.



Profile picture for user Vicki Swan
Pete, 2018-04-12

If the engine is hot 215 degrees and the car is turned off, is it likely the antifreeze resivour purged a cup onto the ground through an overflow? Since the fluid questionable purged the low coolant light had come on... 2008 650i
What is the optimum or maximum engine running temperature for this 8 cylinder BMW?

Profile picture for user MBFanatic

Pete I know it has been a while but what happened is that the car overheated. The high pressure in the cooling system caused the coolant to overflow and spill as you describe. I would top it off for now which I assume that you have already done. But keep an eye becasue you will most likely have the issue come up again. The normal operating engine temperature is in a range of 200 to 220 degrees Fahrenheit.


Profile picture for user Vicki Swan
MacFady, 2019-02-01

Just wanted to note that if you want to do an actual venting using the water pump:
- Insert the key into the dash slot, hit the starter button (but don’t start the engine – e.g. keep your foot off the bake/clutch)
-or if you don't have start button turn key to position 2
- Turn off accessories to save battery or put a battery tender on
- Set the heater to the highest temp and set the fan on low
- Hold down the accelerator pedal (right down to kick down point) for at least 10-15 seconds, you should hear the water pump start
- The water pump will run for 12 minutes, after which time open the reservoir cap and recheck the level, refill as necessary
- You might want to run this twice, if so I'd suggest putting the battery on a tender.

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