Long out of warranty for me. Just don't want to get it all apart to find out I also need a t-stat housing. Not fond of starting a job w/o all the parts. Also not fond of donating any more cash to the stealership.

 

I can't guarantee you won't need the housing, but it's made of hard black plastic, not metal. It compresses the gasket that comes with the thermostat to the cylinder head. It uses 3 bolts. I personally doubt the housing leaks, but I know the gasket can, and it would seem, quite easily from the reports on this thread. My advice (free, and consequently worthless, oops I mean priceless) is to replace the thermostat and gasket, then see if you still have the problem. I'd bet you don't.

cheers,

 

Plastic... I hate plastic... Thanks Dr. Phil! Your free advice is highly appreciated!

 

I just replace the thermostat, gasket and housing on an 04 Cooper. If you place the housing on a flat surface you will see that it may rock a bit. On the one that I did, the brass inserts had moved on two of the three attachment points. The old gasket appeared to be fine. Just my 2 cents worth.

 

I sure hope someone comes out with an aftermarket thermostat housing made out of metal.

 

If it is plastic, then the leaks could indeed be caused by the plastic aging and deforming from heat. I suspect it could eventually crack like a lot of other plastic parts BMW uses for cooling systems.

Tomcatta - If you got some mileage on it, you might as well go ahead and do the thermostat. You get a gasket with it and the thermostats do go bad over time.

 

This is really going to suck swamp water if I have to change out my thermostat every 2 years. What were the engineers thinking?

I hope one of the MINI after market companies like Moss or Minspeed are reading this thread...they would make a fortune on a metal thermostat housing!

 

Alas: I too am now on the Coolant Leak All-star team. Thing is my mini get's parked all over the place, so no puddle to track. Just lots of mysterious coolant disappearance. I think I let her get too low, Started hearing excessive fan leave-on. Went to top off the coolant to find it fairly bone dry. Filled her up, but experienced periodic bouts of temp guage running towards the red. Heater blowing cold etc. Seems she cycles coolant when cruising, but not when idlin / stop and start traffic. So the temp guage systematically goes up when in traffic, and back to normal when cruising. My thought is that it's maybe a basic thermostat leak or such. Since I let the coolant res go to empty now there is air in the system and so even though it's re-filled with coolant, trapped air causes short term over heats. Anyhow, Off to the shop tommorow for service under warranty. Ucanny the explosion of posts on this issue. Seems to be a 30K mile 2006 type of thing. Mines a PW 06 MC right at 30K miles.

 

I wish I had paid a little more attention to the housing design. I wondering if larger washers on the three bolts, spanning the brass inserts to plastic, would keep the plastic housing from creeping away from the inserts. I do think that this is the cause of the leaks. The plastic housing moves away from the cylinder head as it slips from the inserts. This is the same effect as leaving the hardware loose.

 

The other attribute of the light blue coolant is that it doesn't evaporate, unlike, window-washer fluid or water, for example.

Had the leaking thermo housing on my `05 S replaced under warrantee. The SA told me that they are replacing one or two of these per day, so it would appear that most `05-06 cars will be affected sooner or later.

Keep an eye on your coolant overflow tank ...

 

If this occurs again, I will use larger washers to see if it cures the problem once and for all. If things go as I anticipate, I should be taking my MINI back for this in September 08. A metal thermostat housing would be nice!

 

i just got a new thermostat/housing kit; seems like morristown only sells them like that now. it says it's made in brazil, i guess 'cuz tritecs are made there. sure hope someone makes an aftermarket metal housing. maybe m7 would be interested in developing this? =P shouldn't be too hard. i'm gonna install my jcw upgrade kit sometime in the near future and will do thermostat at the same time, also replace the cheap green coolant *****'s auto clinic put in when they did the flush. is it worthwhile to buy the bmw coolant? it's phosphate-free 'cuz of the european water prone to leave deposits but our water doesn't have that problem. another option is to use evans tho that stuff kinda creeps me out

 

Nigel just hit the smurf. Two years, 2 months/ 27,600 miles. Calling my dealer . . . .

 

My '05 PW/B MCS JCW has been dripping blue liquid on the garage floor for 6 months now...2-3 drops here and there. It is a May build '05 with 35,000 miles. I first noticed the blue liquid on my garage floor at about 31,000 miles. After reading this, I went out and checked out the thermostat area, and sure enough, the expansion tank is at the low level line (it's never been that low), and I have dried blue crust around the thermostat/housing area that connects directly to the engine.

I am actually glad it wasn't my A/C! I drove through some icy snow this winter and slid off the road, which slightly dented the bottom part of my A/C condenser about a half inch on the right corner and slightly cracked the radiator mount. No apparent leaks after I took off the bumper for a close examination, but I thought the fluid from my slow leak was from the A/C unit, mainly because of my ignorance of associating the blue liquid with the "cold" A/C! The A/C always worked perfectly, but I was worried that it was a slow leak, and thought that the diminishing amount of A/C juice would damage the A/C unit further! Thank you all for your insight...you saved me some real mental/financial anguish!

 

Thermostat housing is a problem known to your mini dealer. My SA said they get several each week. Mine was replaced at 25K miles under warranty.

 

My '05 is out of warranty--76,000 miles. I had the thermostat housing replaced by Minicorsa. It was toast..no surprise it had been leaking. Silly design issue that's affecting so many '05s.

 

Yep, I changed the housing/thermostat on my 05 MCS at 77,000 and change also. The gasket just fell to pieces, completely brittle when i removed it. I don't know if they changed the design of the housing, and/or the gasket material, though it looked the same.

 

Nice to find this thread. My 05 is just out of warrenty . . . although I noticed some funny temperature gauge readings before my last trip to the dealer under warrenty (not warming up as quickly as normally) I didn't mention it as I was preoccupied with the hole in the year old replacement top. After the 50,000 miles I noticed the fan running when turning off the car in cool weather. . . then I looked under and saw the puddles . . . then checked the coolant tank and saw none.

Ah well, it sounds like a fairly easy first trip into the woods, although, so far I don't see a path through the thicket at the edge of the field. Is there much green briar?

 

One more for the blue fluid leak. '05 MCC w/ 34.000 miles. Going into service tomorrow.

Thanks for the thread!!

 

Thermostat changed!

 

Add me to the COOLANT LEAK list.

I found a blue-ish fluid under my mcsa the other day. Last night I was idling and the temp. gauge crept over 225. I checked the reservior and there was very little coolant in it. I had one of my techs look at it today and there is dried coolant around the thermostat housing.

I have an appt May 17th to get it fixed.

 

My mini is leaking again. Found another spot on the ground.

I cant wait till May 17th to get this leak fixed.

 

Thermostat Replaced Under Warranty!!!

 

Handsome Rob,

Where is your nearest dealer? I think kudos are in order seeing how some of the dealerships are a real PITA when it comes to this kind of thing. The dealerships in Atlanta (Global Imports MINI and MINIs of South Atlanta) have been treating our clubmembers really well when it comes to this type of problem.

Cheers-

 

My nearest dealer is about 50 miles east of me, in Omaha, NE. I didnt have one bit of trouble with them replacing the thermostat housing. The tech even told me that its a known issue.