Overall, I think the R56 coolant systems are aging and will be in need of many areas of repair. We started out just replacing the water pump. The tensioner and tensioner wheel were fine. We then learned that the coolant pipe was broken too. This is the pipe that runs behind the pump, under the intake manifold to the thermastat housing. To replace this pipe, we needed to remove the t-stat housing. I think this pipe broke because the upper engine mount was shot and there was too much lateral vibration on this pipe. As the thermostat unit was replaced in 2012, we did not need to order another one.

If I had to do it all over again, I would replace the water pump, tensioner, tensioner wheel, water pump pulley, t-stat housing, all hoses, and the water pipe along with the engine mounts. All these items need to come off anyway so why not just replace them with new ones while you are in there? I know there is more expense and I get the "if it ain't broke..." thought. However, I think all these components are really wear items and at 10 years and 100K+ miles, it is reasonable to assume these are past there service life.

 

I agree with you. I’ve learned a lot about the R56 through my “hobby that got out of hand” adventure of rebuilding these cars. I’m on my 4th car (all have been 2008 MCS) since August 2019 and I’ve learned that these cars need a reboot once they get to 100K+ miles.
I’ve made it a standard to replace all the items you stated (except the engine mount, all mine have been good) and much more. Due to the heat cycles, low oil at times (when the owner doesn’t monitor oil levels) and the plastic nature of a lot of components, they just wear out and need a reboot.
The difficult part has been the learning curve and the specialized tools needed to rebuild these engines. Perhaps I shouldn’t say specialized as much as I should say unique. Leave it up to BMW to make things different. At the same time, it’s a fun adventure.
If you have the garage space and patience, these cars can be a world of fun. It’s very satisfying to put one of these back on the road and operating like new when the odometer reads 130K miles.

 

Agreed. There is a lot of talk on this forum and others about "problems" with Minis. I agree the chain guide and tensioner is a problem but almost everything else is just needed work after time an miles.

I like the "reboot" mentality. These cars are not hard to work on once you get familiar with the tools and steps. "Front end service mode" is a life changer and knowing how to do it quickly changed my perception of working on Mini.