[Alan l.]

Like the title states make it habit to check your primary and secondary coolant tanks. From my understanding the main system (tank located by the front driver side) is responsible for cooling the engine and turbos. The secondary tank (smaller tank located by the back of the engine cover by the firewall) is for the air to water intercoolers. This regulates the air intake temps and the lower the temps the better the performance.

The primary system has a sensor that will trigger a warning on the idrive when it's low but I don't think there are any sensors on the secondary system for the intercoolers.

What happened with my car was the dealer had to change out the belt/pulley/waterpump on my car so they had to top off the coolant after the work. They did it for the main system but they did NOT do that on the secondary system so my air intake temps were elevated which caused power loss since the ECU thinks the car is heat soaking. It eventually triggered a drivetrain malfunction for high intake temps which is what made me go hunt down the cause.

I found out my secondary system was really low on coolant and I had to pour in approx. 40-50oz to top it all off. The car never warned me it was low and the tank was completely empty! I only knew something was wrong because I noticed the car just wasn't pulling the way it use to. If I occasionally step on the throttle the power was initially there. What I noticed was when I was doing longer highway pulls where the higher the gears the more I could feel performance was being limited. It's accelerating but after a gear or two you feel like you sort hit a wall and the car is trying to over come it. Once I topped off the system and the temps were within normal operating temps all of the power was there again

FYI BMW has a specific way to "burp" the cooling system which is super easy to do. I've done this several times and everything is fully topped off now.

Steps to bleed/burp the coolant system

1) Get in the car and turn on the heat to max temperature (temp will say high) but set the fan speed to the lowest speed.

2) without stepping on the brake pedal, press the start button 3x in a row quickly and wait a few seconds. The cars lights/idrive will wake and you will see a message on the cluster the car is now in Service Mode

3) Press and hold down the gas pedal all the way down for 20 seconds and then release

4) Step on the brakes to start the car and release the brake.

5) Now just don't do anything and let the car do the work. The whole process takes about 11 minutes during that time you will noticed the oil temp gauge start decreasing. You will also notice the RPMs will shoot up to 1500 rpm a few times then up to 3000 rpm also a few times. The rising rpm portion happens towards the middle/end of the process so don't worry if it doesn't do it right away.

6) After about 11 minutes the process is done and you will start to see the oil temp gauge rise back up. At that point you can turn off the engine and you are done.

Keep in mind that during this whole process the car does NOT show you any messages that this has started or ended.

After the engine has cooled down open both of the coolant tanks and check if its at the proper level. Add more coolant if its not and redo the above procedure until its topped off when the engine is cold.



Alan

[GotBeemed]

Please advise on the appropriate coolant to top off the secondary system for the air/water heat exchangers. Thanks.

[GotBeemed]

Part # 83192468442?

[Alan l.]

Originally Posted by GotBeemed

Part # 83192468442?

That is the one

Both cooling system uses the same green coolant.

Alan

[GotBeemed]

Cool thanks