Hey everyone. Today I arrived at work and noticed some white smoke coming from my drivers side engine bay. My car is a 2009 Mini Cooper S with 53k miles. I looked underneath to see coolant dripping at a rapid rate onto the floor. I let the engine cool down and decided to take a look in that area and noticed a puddle of coolant on top of the transmission. My first thoughts were a hose, but it appears all the hoses were fine. I can only assume next would be the thermostat since it is located in the same location. I let the car start after I assembled the car back together and noticed it was not leaking. I even took it for a short drive to come back to see no leak. The drive was only 2-3 minutes around the block after letting the car idle for about 5 minutes.

I attached an image to show where the pooling is. I just wanted to see if anyone has an idea if it is something else besides the thermostat itself, or just the seal. Also, how difficult is it to change it out?

 

This looks like your thermostat housing. It is a complicated plastic part that normally fails between 50k and 60k. Mine just went a couple weeks ago. It's not a difficult repair, but it is kind of time consuming to get to the housing. There is a decent YouTube video on the repair that takes you through the process step by step. I spent around $150.00 on the thermostat housing, Mini antifreeze, and distilled water.


Don't be fooled by that test drive, it will leak again. If you have to order the part, but still need to drive your car, I would highly recommend keeping antifreeze in the vehicle with you, and enabling the water temp gauge if you do not have a ScanGauge.


A side note; My A/C seems to have also failed at the same time as the thermostat housing. Has your A/C stopped working as well?

 

Thanks for the reply. I did some research last night, and I did see a great step by step video for it. It isn't as bad as I thought especially for the limited room the car has in the bay. There is only one port behind the engine that I know will be the biggest struggle with. I have replaced thermostats before, but these were older and bigger cars. I am bothered by the failure you mentioned as I see more mention of it being common. Hopefully replacement parts were made to last longer, but slim chances on that. I haven't checked out the aftermarket yet to see if they make better, minimal to no plastic parts. Also, I hope that Mini has addressed the problem with their new 2014 models, because I am interested in purchasing one in the future. They are really great cars. Since I needed my car back quickly, and due to my horrible work schedule for the next two weeks, I dropped it off at a shop down here in California that specializes in Minis- MiniWorx.

As for the leak, Ive always carried coolant in my car no matter how new, or old it is. It is better to be safe than sorry when out on the road. I was lucky the shop was only 5 miles away so I drove slow there with a halfway point stop to check on the fluid. Of course, no leak. When I got to the shop, I checked and there it was dripping.

I avoided using the A/C after I saw the leak, but it was working fine a few days ago before I spotted this.

I just wonder what will be next after this? I had the timing chain and tensioner replaced with the recall, a water pump, and the previous owner replaced the fuel pump after a recall.

I know stuff happens, but I still love this car.

 

Glad you got it sorted.
I ordered my replacement thermostat housing from ECS, and it was identical to the one I removed from the car. I was not able to find any aftermarket offerings for the thermostat housing. I was able to find an aftermarket water pump made from aluminum rather than plastic. I will probably be replacing that next, as it looks like the two parts usually fail at around the same time.




Oh - The clip on the hose going to the water pump (beneath the intake) is easy to remove, it's just a little tricky to put back in because it's difficult to see back there.

 

I completely forgot about that water pump. I do have it saved from a seller on eBay, and I wrote down the model info. I will move to that one on the next replacement if (and when based on forums) it happens.

I saw another video after my previous post which actually showed the clip location, and yes I agree with you that it would be only difficult to put back in, but definitely doable. The author of the first video made it sound like it was a clamp on there, and didn't show the clip.

This is the greatly detailed video I just saw:
Thanks for your help.

 

That is the same video I followed as a guide. I did not need to cut all of the zip ties or pull the wiring harness. I just unplugged all electrical connections and disconnected all hoses. That, and removing the intake piping and filter housing, gave me more than enough room to work.

 

Also look under Modification - How To link at:

https://www.northamericanmotoring.com/forums/showthread.php?t=211246

It is common maintenence. Good luck

 

Looks like the thermostat housing.

Here is another thread and diagrams that goes well with the above link, which is link in this thread also. There are some other thing to check while you are there.


https://www.northamericanmotoring.co...8-no-heat.html





Thanks