All,

I've got a 2006 Mini Cooper base (R50) with an automatic transmission (CVT). I've started having cooling problems (intermittent)...not sure where the leak is but I keep having to put a half cup or so in the Mini every couple of days. I don't really know where the leak is...haven't been able to find one to be honest and there doesn't seem to be any water/coolant in the oil so I believe I'm good there. I've only go about 58K miles on it...I've had it start to heat up a few times now..yesterday it started heating up so I cut the engine off and it cooled off with the fans...checked the coolant in the reservoir and it was fine (yesterday)...anyway...thinking about changing all the hoses out with silicon but don't haven't done enough research...was really shocked at the prices for OEM so the silicon seems like a better deal even with similar prices based upon what I've read. Anyway...any feedback is appreciated...is this a doable DIY?

I've also read about a seal where the oil filter housing connects to the engine block being a source of problems...but again...haven't been able to locate the leak. At this point it's just annoying and I've been able to keep from over heating...

 

My suggestion....do not use silicone hoses....they actually cause more coolant use for most folks....just go with rubber hoses unless you must have the look....
Most common leak on the non S is the thermostat gasket...built into the thermostat.... So that would be my first thing....hoses...if more than 10 years or 100k could be due....but I have gone 200+ on some cars...no hose issues when I did change them.
The most often neglected item on a mini is the cooling system...
Mini blue coolant was a 3-4 year coolant that needed regular flushing till a formulation change (occurred with BMW too...the bottle went from white to silver...mini bottle stayed black)...new bottle labeling says lifetime..just add fresh to refil when you work on the car...
Other coolant could be used in a mini if you desire..just do a full flush. Bleeding any gen1 min is kinda a pain....just a warning.

 

P.S.
Hoses can be ordered from many places for a good $$
Check rockauto.com....they usually have 5% off coupon....

 

Similar situation to you, car using cup of coolant every couple of days. Faint smell of coolant but no obvious leaks. Was climbing under car when changing front shocks and noticed coolant drips on the ac compressor. Time for a new water pump for me - my car has 108k however and appeared to have had little maintenance (rust in the overflow tank).

Losing a cup of coolant shouldn't make your car start to overheat. So it sounds like the fans are working. I don't know a lot about Minis (only owned 2 months) but generically speaking it is likely what Zippy said - thermostat stuck or water pump not moving the coolant along efficiently enough.

 

You probably do have a leak somewhere and your overheat i'll bet is cause now you've developed air in the system. like the above posts, check the thermostat housing(leak should be visible at the housing or from under the car coming off the bell housing) then check the waterpump(staining on the underbelly splash pan or caked up and coming over the a/c compressor. When the vehicle is cold removed the cap from the thermostat housing and check your level. also remove the bled screw from the radiator hose above the alternator. If ya don't have fluid there then ya definitely have air in the system and need to bleed it.

 

If you are seeing some dried coolant by the ac compressor....
Look around...look at the water pump...the seal on it is likely weeping... An impending sighn of failure... Or the radiator might be failing where the plastic ends are crimped to the metal middle part....a common failure with this modern style design on many cars....again... Not super $$, about $100 for an exact fit rad from rockauto if you are planning to diy it.

 

Wow...appreciate all the responses. These have all been helpful. I'll check around the water pump as suggested and see if I can find the culprit. The hoses do seem to be fine so I'll leave them alone for now. I changed out my automatic transmission filter and did a complete transmission fluid change using the Redline Synthetic CVT transmission fluid. I don't have access to a Mini dealership but we have a BMW dealership...from what I read the BMW coolant is the same as the Mini...can anyone confirm this? I bought a gallon that must be mixed with distilled water...or is it 1.5 gallons...hmm...my memory isn't great and I'm not currently at home. ...meant to say I really enjoy DIY stuff if it's not over my head. I've got a Mini service manual...the one by Bently.

 

Yup...BMW coolant= MINI coolant.... Both are blue too..lol.
Most folks use a 50% water mix....others are possible like 60%/40%...the info on freeze levels is on the bottle.

 

Awesome...thank you for the info. Will probably go ahead and get a new thermostat/gasket just in case that is the problem.

 

I have to disagree with the use of silicone hoses. I have and many other been using them for years with zero issues.

 

I add my vote to the "stick with rubber hoses" club. See my post about my experience here:

https://www.northamericanmotoring.co...one-hoses.html

As others have mentioned, the thermostat gasket is the likely culprit. Had to replace mine a few years ago. It's the only place mine has leaked coolant.

Also, my guess is your hoses are fine. I replaced mine about a year ago, but they definitely had more life left to them. They can easily go 10 years, likely 15.

 

I would go ahead and change the thermostat housing as I would bet my paycheck that's where the leak is. I've had the exact same problem twice now (on 2 different cars). Also, I would suggest flushing the whole system and switching the antifreeze to GM Dexcool. Basically the same as the BMW stuff but available everywhere and about $8 a bottle. I've been using it for years with no issues.

And to be clear, you must flush the whole system to switch. Don't just start adding the GM stuff.

 

Don't want to turn this into a coolant type war thread, but the OP should at least read a little about the supposed problems Dexcool can bring. I personally wouldn't put it in my MINI, just to be on the safe side. Google "dexcool sludge."

Also, from my understanding of it, Prestone Extended Life is a very similar formulation to Dexcool. I believe the closest to BMW coolant that is widely available in the US is Zerex G-05.

BMW coolant is basically Zerex G-48, which is hard to run by in the states.

Here's an interesting thread on the differences between G48 and G05:
http://www.bobistheoilguy.com/forums...&Number=613531

I guess the real key is, whatever coolant you go with, change it often enough so the additives don't run out and start causing rust and corrosion within the system.

 

+1
And dex cool IMO is EVIL....NOT MADE FOR MINI'S. just don't do it.

 

Didn't know Dexcool was so hated. Maybe next flush/change I'll go to Prestone. But honestly, I think if you flush your system regularly (every 2 years) you should be fine either way. I've heard stories like this for the past 20 years (ie. don't use Valvoline because it will ruin your engine, Castrol causes excessive sludge etc) but I have never personally met anyone who has experienced said problem. Most issues are caused by inattention to maintenance, not necessarily what oil/coolant you use.

Anyway, my point to the OP was change your thermostat housing, flush the whole system, and switch to a cheaper, widely available coolant. Makes life a little easier.

 

My call given the year that it is your T-stat gasket. A common problem and hard to spot. replacement is not bad. jack up the car and look at the base of your transmission. if you see coolant it's likely the T-Stat there is a good thread here on replacing.



edit: here is the linky
https://www.northamericanmotoring.co...at-change.html

 

Biggest issue with dexcool...you only want to use it where it is speced....early on there were some cars it was used in...had some failures in plastic parts...it ate them... That and if the block is not 100% flushed, Dex will turn to jello when it combines with the remaining coolant....stuff turns acidic when it is used up....2 years is fine...think it is speced for like 6yrs/100,000 or even 150,000 miles....just not what the car was made to use...or even close...different chemical's.
G-05 is pretty close... Mini/BMW stuff is the stuff...but I would use regular green or yellow before I went to Dex.....but I bet you are better off than doing what some folks do...and just ignore the cook ng system....kinda Scarry with an IRON BLOCK.....
But 100% agree....lack of MX causes many more issues than regular MX with an imperfect product. If it works for you...run with it. If it has been in use for a bit...no leaks from the water pump seals or other gaskets...you are a pretty safe IMO. Just consider most coolants are formulated for use with aluminum blocks.....

 

G48 is easy to find... Just not on the shelf at Walmart...

Look harder and it's easy to get. Online it's easy to get too...

I would never run a Dexcool/ oat coolant in a Mini.

 

So I went to the garage this morning to look at what I've been using for coolant. All this reaction led me to do some more research on the topic. Turns out I'm using the autozone version that is "compatible" with Dexcool and all HOAT antifreezes. So basically, it is the same as the Prestone version. My mistake.

Tons of reading on the subject really didn't change my mind much though. I read about 100 complaints on the NHTSA site and you could boil most of them down to poor maintenance. Does Dexcool eat head gaskets? Maybe. Does inattention to your car lead to the same problem? Yes. I don't believe the type of antifreeze you use will by itself cause your engine to self destruct. As with poor health, many factors combine to make one big problem. Heck, most of us have had to change a leaky thermostat housing (I've done 2) and most were using the OEM antifreeze.

That all said, I do agree Dexcool isn't designed for our cars and I don't want to endorse anyone using it. Best practice would be to use the Mini approved stuff and if you can't do that, use the Prestone or equivalent stuff. I apologize if I misled anyone.

 

No problem....from wijipedia....
OAT vs HOAT
No worries...we are all here to learn!

 

And just for those who don't want to read it all...
DEX is NOT compatible with silicone rubber....
so not safe to use if you switch to silicone hoses!!

 

Wow...I've been out of the loop for a few days...lots of activity here. I'm pretty sure I've narrowed it down to my thermostat housing...was very surprised to find they are made of plastic...anyway...I've got a new thermostat, a new thermostat housing on order as of this AM...and a new coolant sensor. I put some coolant dye in the radiator and looked at it under the UV LED light...everything seemed to be coming from the housing.

 

I believe you are spot on...I just ordered a new thermostat housing this morning and already have the thermostat w/gasket ready to go. I also got a new engine coolant temperature (ECT) sensor.

 

Just replaced my entire cooling system - from heater core to water pump. The only thing that wasn't replaced was the expansion tank. $$$

Glad to hear that you narrowed your leak down to the housing.

 

Well...only time will tell but I got the thermostat housing, new thermostat & gasket, along with the ECT sensor changed. Took a while because I wanted to make sure I flushed the system completely before I began. I could not find nor did I really want to find the 14mm coolant drain plug [SIZE=2]located at the rear face base of the cylinder block adjacent to the starter motor[/SIZE][FONT=Verdana][SIZE=2] underneath the exhaust manifold heat shield (if looking down at the engine). Got this info from an article on Pelican Parts website

http://www.pelicanparts.com/techarti...ant_Change.htm

I also have the Bently Service Manual for the 2006 Mini Cooper so I took most of my que's from it.

To flush the system I removed the lower radiator hose and let the system drain out. I slide the clamp back to allow me to take the hose on and off through several flushings using distilled water. I actually went through about 4 gallons...I'd drain the system, fill it back up, turn the heater on and start the engine...run it up to operating temps so the thermostat would open and then add a little over 1/2 gallon...that was about all it would take...shut it down and drain it again. Not sure how many times I did this but the water only had a very light tint of yellow coolant that I had been using over the past month because it is cheap. I was losing about a cup a day just running around town. Anyway...after the system was well flushed I followed the steps to remove and replace the thermostat/housing etc. Removed the battery, battery box, and air box. When I took the housing off I had to pull the thermostat out with a pair of pliers...the gasket was not very pliable and crumbled when you flexed it so that definitely seems to have been my primary problem. Replacing the ECT sensor was pretty straight forward as well...wasn't sure at first how to get the plug off but figured it out after a few minutes and did not damage anything. Got everything back together in reverse order. Because I could not completely drain the system I decided to add only full strength BMW coolant (blue stuff). So I measured out exactly 1/2 the full capacity of the system. Mine is a Mini Cooper Base (R50)...so full is 5.6 qts...2.8 qts is exactly 1/2 which would leave me with the 50/50 ratio. I then mixed equal parts of distilled water with the remaining coolant and filled the [/SIZE][/FONT][FONT=Verdana][SIZE=2][FONT=Verdana][SIZE=2]reservoir [/SIZE][/FONT]with this coolant. Started the engine with the heater on full and began adding the full strength coolant...used the bleeder valves to purge the air in the system...got almost all the coolant in the radiator before it showed full...ran it for about 10 miles and let it cool overnight...added about 1 cup of coolant to the reservoir and added the remaining full strength coolant (about 1/2 cup)...got it up to normal operating temp and ensured I was not getting any more air out of the bleeder valve...all seems good to go...


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