I have a 2006 Mini Cooper S with 17,000 mi on it. This morning while backing out I noticed a light bluish oil pool on the floor. It was directly under my engine (driver side). I'm suspecting its coming from the transmission. Does anybody know what color is the transmisson fluid? The car still has the original transmission oil.

 

It's either anti-freeze, or you have a leaking motor mount, however the motor mount that usually leaks is the one on the right side of the car....

 

I'd guess cracked cooland reservoir. Check and see if there is coolant in it!

 

Have the dealer check the thermostat housing for cracks.
Your still under warranty.

 

Thermostat housing leak.

 

Ussually just needs a new seal, seems to be really common in 05+ R50, 52 and 53 models.

 

I have an '06 and had the same thing. The pool isn't very big right? Mine was a cracked thermostat housing. Didn't leak when warm just when cold. Dealer replaced the thermostat housing and went ahead and replaced the thermostat, and coolant resovoir. I was considering flushing the coolant the following summer but this resolved that.

 

I have a 2006 with 20k miles on it, and on mine, the leak was a bad radiator cap.

dp

 

I've replaced the thermostat and integrated gasket twice now. The original gaskets were made of a material that leaked, and the newer/replacement ones are a different material (old = white, new = clearer).
The dealer said they had never seen a cracked thermostat housing, only leaking gaskets (and very many of them!) I imagine that the dealer is replacing the thermostat housing to increase margin (whether in or out of warranty) and to be overly cautious.

 

I also suspect you have a leaking theromstat housing/gasket. Very common with the 2006 cars. I would only see a puddle when backing out of the garage in the morning.

 

Thanks for all the replies. I removed the air intake housing today and it is coming from the thermostat housing seal. I guess its time to replace the thermostat and the gasket. Again, thank you all for your time.

 

I discovered the same issue about 2 months ago and now am fed up with pouring in Prestone 50/50 every other day. I've ordered my thermostat housing and new thermostat from Mini Mania and will hope that resolves the issue. Thanks for your posts! Helps me narrow it down.

 

i also have a 06 mini s that has the "small blue puddle" after sitting overnight. is it the t-stat gasket or t-stat housing gasket that commonly goes bad? any info is appreciated

 

Are you using the green Prestone? If so you're using the wrong antifreeze!

 

The Thermostat housing and Thermostat gasket is the same gasket. And yes it is the most common gasket to leak. We have the newest upgraded version of the thermostat with gasket in stock. The white colored gasket is the old one that is more common to leak.
http://www.waymotorworks.com/product...7&cat=0&page=1

 

uh oh... I just add the bad thermostat housing also, and topped off a few times before taking it in. have to go look at what I used though...

Why is that wrong?

 

Despite Prestone's TV ad claims, green stuff usually does not mix well with BMW antifreeze (VW's have the same issue). It can react badly and turn the coolant into something that resembles peanut butter...

Use ONLY MINI/BMW coolant and ONLY distilled water (impurities in tap water can also cause problems).

 

If you doubt what IanF says, try this: Draw an ounce or so of the BMW coolant from the coolant tank with a turkey baster or coolant tester and put that sample in a glass jar. Then add an equal amount of conventional coolant and stir it up. It will quickly react to form a slimey sludge. If you've been doing this to your cooling system, you'd best get the entire system purged.

 

BMW/MINI coolant is a hybrid of sorts when it comes to beaing a automotive coolant. That means it is not the same as the yello, green, orange, or pink. It is not the same, nor is it compatible with so called universal antfreeze (many debates here....just know that universal stuff when mixed, fails the SAE requirements of the stuff it is trying to mix-with....so water would be better IMO). The one aftermarket brand that meets BMW/mini requirements is zyerex g-05 think..... One of 3 versions that zeyrex makes, one for the traditional yellow/green, one for the pink/orange, and one for the BMW/mini, the blue. Any of these 3 antifreezes when mixed together can breakdown, createing acids, gells, etc....all bad things in any motor. When improperly mixed, thee combo have been known to dammage plastics, metals, and eat gasket materals. Do a quick google search...dexcool problems, etc, and you will be like wow. If properly flushed, different antifreeze can be used in a refil, but most reccomend sticking with the oem since it is pretty good stuff, not to pricey, and the expense of flushing eats up any savings garnered by the new fluids longer life.

 

I had the same leak, Mininme, at 15000 miles. 2006 MCSC also. Thermostat seal leak.