Loosing coolant. The Dealer said they pressure checked twice and found no leak. Has anyone had a similar problem? "06 Cooper S

 

The most common coolant leak is at the Thermostat Housing & Gasket. Mine leaked only at night after I parked the car in the garage. There would be a little puddle under the car in the morning. Depending on engine temperature (part expansion) when pressure check is performed the leak might not be observed.

If the Thermostat Housing is leaking you can usually see a little liquid puddled near the housing or at least some dry white residue left over from the leaked coolant evaporating.

The dealer should be very aware of this common problem.

 

mines leaking from the thermostat housing, it won't show up in pressure tests.

the thermostat+gasket costs about $40 and whatever new coolant costs now.

 

3rd vote for thermostat gasket. Mine leaked so little, it left zero visible trace. I don't have the equipment to pressure test, but I'd wager it would not be detectable. Unfortunately, the damn gasket is not available without purchasing the thermostat - hence the high price Rusty mentioned. I'd suggest getting from the dealer, or a well trusted specialist. The word on the street is that MINI revised the gasket a few times, and you want to ensure you have the latest part. Although I might be confused with the revisions to the oil pan gasket. Either way, I'd go OEM on this one.

Edit: And welcome! You should really post an intro when you get a chance.

 

Yeah, either thermostat housing or leaking expansion tank. Both are known issues.

I replaced my expansion tank, thermostat / housing, and all rad hoses when I got my 2003 (in 2011) just to be safe.

 

Here is what the thermostat housing looks like and a place to purchase if you want to DIY:
http://www.waymotorworks.com/r53-the...t-housing.html

You can go to the How To section under the Library tab to find instructions for replacing the housing.

 

I think it is the thermostat gasket as well. My gasket broke into 3 pieces as soon as I removed it. I don't think it's the housing..call Way first.
http://www.waymotorworks.com/thermos...t-r50-r53.html

 

Here is a link to what the expansion tank looks like and a place to purchase:
http://www.waymotorworks.com/coolant...2-r53-oem.html
The tank is mounted in the engine compartment on the firewall.
The tanks frequently leak at the middle seam. If leaking you should see white residue on the side of the tank. The earlier years had more problems with the tank leaking than the 2006.

 

well, recently out here in Chicago, Ive been seeing the o-ring on the water pump, that goes into the housing on the block, leaking coolant. Sometimes it leaks on the floor in the same area as a thermostat gasket leak. No real easy way to check for this leakage without getting under the car, and even then its a bit of a PITA. This gasket usually wont leak until operation temp has occured, or a drastic change in weather temp.

 

Had a coolant leak in Feb '12 on my 06 mini-s and had the thermostat replaced - now it's May and it's leaking again - not noticeable - but the coolant thing is empty and the fan comes on when the car stops. What should I replace now?

 

The common leaks are:

- thermostat housing
- expansion tank

The expansion tank leak is hard to see, usually on the bottom / back. I had to replace mine - and some people have replaced them more than once.

 

BuYou need to be a bit of a detective....
look at the common stuff as stated above...
then look at your hoses, and the the radiator (the most common leaks are around where the metal tubes are crimped to the plastic sides, but with a low front a road debris, snyplace is possible)...maybe even the weep hole on the waterpump....as the miles and age of the cars go up, the number of things that can be causing the leaks go up...

 

Thanks! So do people actually keep their mini's forever or are the repairs too frequent and not worth it.

 

Imo it kinda depends....
The 2005+ gen1's had many improvements, but the older ones (2002+) can be pretty relilable...alot depends on how the cars have neen matained, and more importantly, driven by prior owners (if applicable). Many mini's were driven hard, tracked, and abused...but many more were weekend cruisers or commuters....
one thing that makes a huge differance seems to be finding a competant mini centric shop...many of them know the cars better than the dealers (many mini dealers opened in the last couple years are new, both in ownership, and employees, and some know amazingly little about the pre-gen2 (the r50/52/53) mini's....).
Sometimes just a bit of knowlege can make a huge difference. Heck, some of the best mini mechanics have gone out and started mini centric shops...so they were both factory trained, and highly experanced...WAYMOTORWORKS.COM, a sponsor here (i actually have visited them down in GA, on a bussiness trip), sells great parts for diy'ers and has great knowlege to back up the sale, and any questions that come up.

 

First step is to refill the overflow tank w/distilled water and check every day or so. Could be that you had an air bubble and just hadn't noticed. If it still appears to be dropping, see previous posts.

 

Like another user mentioned, you will see a trail of white powdery dry liquid stain near the leak. My thermo housing leaked the first time 2 years ago at 14K. There's a trail going from the bottom part of the housing, to the diff housing of the tranny, down to the bottom tip of the tranny.

Sadly to say, 2 years later after just 6K, I found leak again last week. I'm seeing green dry crystalized stain of the upper part of the housing and greenish white stain on the bottom of the diff housing.

I think we need to get some of NASA's engineers to figure out a fix for us instead of keep on replacing the darn thing. Every time, there's no drip mark or puddle on the card board, it seems to happen when the is cooling down, and it evaporates by the engine bay heat. I just keep monitor the expansion tank level and refill as needed.

 

I called and asked for a quote for thermostat and thermostat housing....they indicated 375 plus tax which includes a coolant flush.....

I ended up getting out the door for $400.00 at Seattle Mini.