Rizbel

I just put a new thermostat in my 545i (N62) and it was easier than the 330i(N52). Access is easy with only a nut and three screws, a cable, and a hose to remove.
Pictures to follow with step-by-step procedure.

Rizbel

Raise car on jack stands safely. Use proper tools designed for the job.



Remove splash shield. (968TurboS photo)


Draining coolant
Allow engine and coolant to cool before proceeding.
Remove cap from the expansion tank and place pail under radiator, then loosen petcock (red) to drain coolant.
Remove reinforcement plate and remove engine block drain plug from left side of engine and drain coolant.
Properly dispose of drained coolant.

Adding Fresh coolant

(50% BMW antifreeze and 50% distilled water, 15 US qt) and venting system at the same time.
-Switch ignition ON without starting engine.
-Set blower fan to low and temperature for driver and passenger side to full warm. Set seat heat to MAX if available.
-Fill expansion tank slowly until Max level.
-Leave cap open and run engine at idle for 1 minute.
-Adjust level to MAX and close cap.
-Run engine to operating temperature.
-Shutdown engine and after engine has cooled, recheck coolant level.

** Disclaimer**
I hold no responsibility for any damage or injury occurred from following this DIY. Proceed at your own risk.

Next: Expansion Tank removal and installation

Rizbel

Expansion Tank removal and installation

-Drain coolant (see post #1)

-Remove hoses (yellow arrows)
-Remove 2 hex screws (red arrows)
-Lift expansion tank to release cable connector (green) to coolant level switch.
Make sure rubber grommet is present and securely mounted.
-Installation is reverse of removal. Ensure pin at the bottom fits securely into the grommet.

Fill and vent system (see post #1)

Next Thermostat removal and installation.

rctmthouse

When I replaced my water pump and thermostat, I didn't think about draining the expansion tank. I only drained the coolant from radiator through the plug and of course all the fluid from the hoses leading into the pump. Following the advices of some members here, I also flushed the system with water and let it fully drained over night since I was getting dark.

rctmthouse

never mind, I just realized I did use a hose to flush the expansion tank so unless something else goes wrong with the system, hope not, I don't see the need to remove the tank now.

Great job Riz. Looking forward to any other DIY you're planning to do.

Rizbel

I forgot to mention the reason why I needed to get a new coolant expansion tank. The brown plastic floating stick has become brittle and broke from its base.
I fear that the pieces might get inside the engine block and mess things up.

rctmthouse

Good point, will check it tomorrow to see how's mine?

Rizbel

Actually I did a mod while the car is up on jack stands and front bumper off. Since the halogen lamps are now disabled via NCSExpert coding (no DRL and switched Flash-to-pass to the xenon lamps)
and I don't have fogs mounted (genuine M5 front bumper has no fog lights), I rewired the halogen lamps to come on when the fogs are switched on. Just don't tell Iceman .

rctmthouse

Why the 2 scoops?

rctmthouse

BTW, do you happen to know where I can find the DIY on how to remove the front bumper? I assume I can remove it from searching for the screws but after Turboawd mentioned about how the active stabilization module was located behind the wheel weld, I have to make sure before removing the bumper. Was thinking of ordering the front bumper and have it shipped, painted instead of paying the local excessive charges.