Has anyone here flushed the radiator on the Cooper?
It appears to be a rather large job.

 

It shouldn’t be too bad. The lower hose is split in the middle, so removing one of the clamps will dump just about all the coolant out. Then, find an upper hose to use for flushing. The hardest part will be making sure you get all the air out when refilling. I have a vacuum fill tool that does an excellent job, but others have had issues trying to “burp” with the bleed valve on the thermostat.

 

Ok, thanks 👍

 

Just curious: what made you think that?

As njaremka already mentioned, making sure no air pockets remain in the system is the "hardest" part of it.

If you do not have access to a vacuum fill pump:
1. open the bleed valve on the thermostat housing
2. pour coolant into the expansion tank until no more air or air bubbles come out the bleed valve.
3. close bleed valve and continue to fill coolant into the expansion tank until full
4. set the heater to its highest and the ventilator to its lowest setting
5. drive until the engine has reached its regular operating temperature, preferably above 100° C (*)
6. with the engine running, carefully open the bleed valve until coolant with no bubbles comes out
7. re-fill coolant into expansion tank until max level.
Repeat until the coolant level in the expansion tank does not drop anymore (assuming no leaks).

*: You can use the hidden menu to monitor coolant temperature. Just make sure that no air comes out of the bleed valve, otherwise the reading may be off.