e53 3.0i auxiliary fan troubleshooting...

[topspeed]

Hello,

I'm new to the forum and new to BMW ownership. I have bought an 2004 e53 3.0i 7 month ago and everything has been going good until now.

The last 2-3 weeks i have had some problems with the AC not blowing enough cold air on freeway. On city and traffic the AC seemed ok. This was until yesterday when on freeway driving the car cracked the expansion tank and leaked coolant. I didnt let the car overheat and stoped.

We have replaced the expansion tank. We have also replaced the small thermostat because it cracked during expansion tank removal and we also replaced the water pump since we were at it.

We have done the proper bleeding procedures and the car seems ok for now but we are trying to figure out why the expansion tank cracked.

As you can see in the video attached the auxiliary fan gives a few back and forth before going on, thats why we think that it might be going out.

We have also triggered it on ISTA/D and the fan will make some small noise and then go full speed but we are unable to check low speed.

Also the coolant tube near the radiator cap seems too hard to press when car is hot. Is this normal since it is a pressurized system ?

Any help would be appreciated. Thanks