It's about that damn thermostat housing
 

2007 R56 Hatchback

Left home at 0430 today, 2-hr drive to Mini dealer; check engine light was on.

Thermostat problem.

Replaced thermostat and thermostat housing; rewired thermostat connector (old one had "melted").

This is the second thermostat housing.
Dec 15, 2016; 88,831 miles
Apr 13, 2021; 115,782 miles

Anyone else replaced three? Four? What's the world record?

Yep! I had an '07. Went through 3 of them before I sold it.

Hello,

Fwiw- I highly suggest you replace water-pipe anytime you replace thermostat-housing. I have a 2009 MCS with 170K miles and have been through four of them.

Good luck.

W

When I changed the thermostat housing and waterpipe, I went into the same situation of ECT(engine coolant temperature) sensor not sending out signal to DME computer which wreak havoc on hard to start. I ordered a new plug and wiring terminal and ECT sensor from a dealership thinking what can go wrong. The DME should have picked up the ECT signal to make starting so much easier but NNNNO! It turns out that that the new wire and plug couldn't make a solid connection to the ECT therefore, I end up hooking the the wires directly to the ECT without the plug housing.

Water pump tube too short ???
 

Just got a 2007 Mini (base model). Mini dealer said thermostat failed and it was $900 + to repair. I figured I could do it so I bought the housing from the dealership for $130. Got it done a couple of days ago but it leaks where the clip attaches to the tube. Took apart again and it looks like the clip groove is still outside of the tube. It’s like the tube is about a 1/4 inch short. Any ideas ?

If you are at that already why don't you change the water 💧💧 pipe as well it's very cheap for a piece of mind. The water pipe or crossover pipe whatever name you want to call it. It pushes in the back of the water pump and the other end fits into the thermostat housing. Then the clip fits into the groove to lock both pieces together make sure you have the thermostat housing pushed up to the mating surface.

Hello, (I have a 2009 MCS)

When installing new thermostat housing, it's critical to lubricate the o-ring on 'tail-section' of housing that connects to water-pipe. I used dielectric-grease (what I had availble and it worked great). And, if you are replacing water-pipe, same goes for the o-ring on water-pipe end that goes into rear of water-pump (has to be much lubricated). If o-ring is dry, it's practically impossible to get it to seat properly.

Good luck,

W

The problem seems to be that the groove on the t-stat housing next to the o-ring groove, that the clip uses, doesn’t go into the tube far enough to fasten it to the slots in the tube !

+1 use grease or it will not go in all of the way!