Expansion Tank

[bdcanetti]

Originally Posted by gregg3gs

what!!!!?????

Sorry for misinformation. Hope you are not offended, I will double check.

I'm not offended at all! It's just a crappy lesson all us 4.8i owners had to figure out. Any other BMW I've had you had to do the procedure as you explained. It took a bunch of reading and talking to my service department to learn there is no bleed procedure on the 4.8i.

[wsmeyer]

Still don't know what engine OP has but here's the instructions for the N52 I6:

Venting cooling system: Note:
In the process of pumping the reservoir tank cover is not open.
1. Connect the charger.
2. Turn the ignition switch.
3. Set the heater to maximum temperature, the fan on the lowest speed.
4. Press the accelerator pedal all the way down and hold for 10 seconds. The engine will not start.
5. Pressing the pedal starts pumping process, which lasts approx. 12 minutes. (Electric coolant pump is activated and approx. 12 minutes automatically shuts off).
6. Then, using the measuring vessel fill in the expansion tank for another 300 ml of a cooling liquid in excess of the maximum (see. Fig.).
7. Check cooling system for leaks .
8. If you want to repeat pumping (for example, in the case of leakage of the cooling system), switch off the entire DME (remove the ignition key approx. 3 minutes), then repeat from step 2.

Close tank.

[Sam617]

Just finish changing the tanks, very easy to do, a ten minutes job!! I have a 4.8 so I follow the wsmeyer advice on how to blurp the system. Thank you all, Sam

[creisa]

One other thing, changed tank, cap. Make sure to check small hose that runs on top of tank- mine was brittle and broke. Luckily I ordered all parts for like 120 and 15 minutes later good to go.