I recently bought a 2011 R60 S All4, which after several weeks, the idiot light showed it was running hot for about five minutes after 4-10 miles of driving. Scan showed a temperature system issue, so I replaced the temp sensor, but it wasn’t the issue. After chatting with the folks at Turner Tuning, they suggested the problem was that the thermostat wasn’t opening fast enough, and I needed a new assembly, which I bought. However - is it possible that the coolant sensor is the culprit, and can the sensor be replaced instead of the entire housing, ( which looks like a bear of a job)? Cheers and thanks!

 

You may want to check your VIN to see if your vehicle falls into this temp sensor issue:
https://www.northamericanmotoring.co...or-recall.html

Otherwise, assuming you've eliminated any coolant condition/levels issue (tried a flush?), a thermostat issue does seem to fit with your symptoms. But I'm no expert, nor have I had to work on anything cooling system related on my R60 yet.

 

Pretty sure the 2011 had the all-in-one thermostat housing, where the thermostat isn't replaceable, the same as my 2013 has. So I'm not sure what you mean when you say you bought a "new assembly". The temperature sensor itself clips into the housing, and it is replaceable.

The new version has the housing with a replaceable thermostat, but you also have to buy a wiring harness adapter. Be careful ordering...there are two versions, and one will not fit your turbocharged engine.

It's not the most fun job, but it's not awful either. Get yourself a hose clamp tool to get at the buried clamps, and you'll have an easier time of it. I bought this one off Amazon and it worked just fine: