I bought my MINI about 2 weeks ago, when my Dad picked it up (he picked it up for me in Kansas City because it was such an amazing deal), he noticed that the coolant reservoir was completely empty. He wasn't that worried about it because there were no signs of leaks anywhere, figured the guy just never checked it because he was older and not in the greatest of health, plus the car only had 18,750 miles on it.

Well, my younger sister drove it down to me 1000 miles, but before she did that my Dad went through it and topped off all fluids and even drained/flushed the radiator and put brand new coolant in it. I now have almost 21,000 miles on it. I was out washing and waxing it this morning and decided to check the fluids as well to make sure nothing was leaking. I became quite scared when I noticed that the coolant reservoir was completely dry again, no visible leaks at any of the hose connections either. And there's nothing on the metal heat shield below the reservoir either.

I live 2 hours away from a MINI dealership but am a little scared that this might be something more serious, like a leaky engine gasket (as my Dad mentioned was a possibility when he told me the coolant reservoir was low). I already know about the coolant reservoir being leaky (having a split on the back of it) because it is milky-white plastic and not the new yellow plastic style, but I can't see any signs of leaking on the back of the tank. I've checked the hose connections as best I can see and nothing looks to be leaking either.

If I can't find a source of the leak, does that mean I have a leaky engine gasket? I need to see if someday this week I can take a day off work and head out to El Paso to the MINI dealership and have them look at it. But I'm a little scared to do that because I'm afraid I'll rack up a hefty repair bill very quickly...and that's just not good at all!

Any thoughts?


After looking around more for a leaky hose, I found a puddle of coolant directly below the positive battery terminal, pooled up in a cup of heatsink material in the transfer case, transmission or whatever that is. I went ahead and topped off the coolant reservoir and rinsed out everything below it, even washing out the puddle of coolant so I can see how quickly the puddle reforms. If it's a slow leak, then I'm really hoping it's just a hose or connection somewhere that I just can't see.

 

get it topped up to where you know it is correct. The first fill you mention your dad did may not have been enough if there was air in the cooling system, in which case by the next few cold hot cold engine cycles it could pull the newly added fluid out of the bottle.

One you have the bottle for sure filled correctly, now monitor for drops. If it drops, you are thinking of three of the possibilities: head gasket and clamp points/hoses, plus cracked bottle. Add to it, small leaks at radiator, plus the heater, and leaky water pump bearing. I'll skip rare scenarios like internal cracks. You might think the leaks would show up on the ground, but if they are at a hot surface, the fluid can just evaporate off. Assuming you have antifreeze in it, look for mineral deposits with some faint blue/green to them (like the Mini antifreeze color). In the case of the heater, you would likely smell something a bit sweet when you use it, and windows are more prone to fog up.

Finally, various classic home mechanic tests (i.e. not using leakdown test equipment) for head gasket include looking for white smoke in the exhaust--water vapor, but more than just the cold start up you notice in winter months. Also look for milky color in oil under the fill cap, or obvious bubbling in overflow bottle even when the car is still pretty cold (shortly after cold start). Any of these symptoms are not good, and strong indicators of a gasket issue. The water vapor in exhaust isn't so obvious in hotter months or a minor leak, but on other cars where it happened to me, it blew a whole lot of white smoke and was a dead giveaway in those cases.

 

I had the same problem and it was a leaky thermostat housing, which is very common on the 1st gen cars. Inexpensive fix.

 

Leaky thermostat gasket, cheep and easy to fix. Mine leeked for several weeks before I replaced it. You can order it and have it shipped. Easy to replace. Just keep your fluids toppped off until you replace it.

Brad

 

For starters, he actually drove the car to/from work (30mi each way) for a couple days after flushing the coolant and said it was holding perfectly at the max level. I started the engine up after being cold and looked at the coolant reservoir and didn't see any bubbling or milky color in the oil, so that puts my mind at ease a little.


If this is the case, should I just replace the entire thermostat, gasket and housing all at once? I assume I'll need to drain the radiator again, right?


This sounds a little more promising that more people are saying this, roughly how long of a job is it to replace? I'm pretty handy with tools and work as a telescope engineer, so I definitely am able to understand how things work and how to take stuff apart and put them back int he right place without extra parts . But, is it easy to get to to replace or is it an involved process? I don't have a repair manual yet, so I'd be doing this rather blindly. Is there anything I need to watch out for?

 

Never fear, NAM is here. Instructions here, complete with pictures.

No need to drain the radiator, and it's not too complex. See the threat and ask if you have any questions.

 

Awesome, thanks for the link! I must have skipped over that thread when looking through the How-To section. Might need to relearn how to use the search function in specific subforums

Yesterday, the coolant level was perfectly level with the top of the Max Line, and this morning after it cooled off overnight, it dropped down about 3/8", so it definitely needs to be taken care of, but in the mean time I'll be checking it daily and looking for puddles or obvious signs of drippage.

I also checked around the thermostat housing as best I could, and found at the base of the bolt heads, there was some ever-so-slight green crust that had formed. After looking at that how-to thread, it seems that some signs it's definitely the thermostat/gasket is coolant residue underneath the thermostat housing flange, which makes sense that it'd also seep out through the mounting bolt holes.

 

I've never heard of one failing catastrophically, they just keep pissing on the driveway/garage until you fix 'em.

 

Ha, well that's good to know. My Dad originally thought it was an engine gasket or a faulty water pump, both would have been expensive repairs and I didn't want an expensive repair within the first month of owning my MINI!

And I guess I'm lucky about it pissing, I live in the mountains and my "driveway" is a combination of dirt/rocks/pine-needles and various twigs. So I'm fortunate enough that I don't have to mop the mess up!

Found the Thermostat (Wahler) and Thermostat Housing (OEM MINI) from bimmerspecialist at 34.99/40.99 and shipping is like $1.24 via USPS. Think I'll just order these later today and forget the dealership. They just called back and quoted me $472.35 installed. The parts were $43.25 for the thermostat. The rest of that was labor!

So, I think i'll be ordering the thermostat/gasket, thermostat housing and auxiliary audio kit for $113 shipped from bimmerspecialist!

 

I recommend the OEM thermostat over the Wahler. I tried them, but the gasket didn't fit the housing very well and had one come back later. The new OEM one has bee improved and works great.

You prob don't need the housing, 99.9% of the ones we do just need the thermostat

 

Thanks, just ordered the OEM thermostat, hoping to get it in my hands by this weekend so I can devote an entire day to the swap. I live 30 minutes up in the mountains so if I have to run to town to get fluids or a tool, it'll take me a while and I doubt I'll be able to make the swap during the week.

Now I just get to find a way to rig up a catch pan for the coolant that I'll be draining without letting it drip all over the engine and pick up dirt. Going to try to get an extra gallon or two of coolant while in town tomorrow (already have roughly 3/4 of a gallon, brand new stuff that I just opened to top off the coolant tank the other day).

 

Definately a thermostat-related problem. Had this exact problem with my R50.

 

My $0.02 - Don't even THINK about trying to catch the coolant coming off the engine. First, it will be dirty, and second, not much comes out. False economy in a big way. You're pulling the thermo near the top of the engine, and the overflow tank won't drain if you don't open it. You're better off just getting a bottle of distilled water and topping it off with that rather than trying to reuse coolant.
The OP in the 'How To' does a LOT more work than necessary to get the job done. See later posts. You don't need to remove the ECU, just put it to the side. Don't need to drain the rad, either. Only a small amount of coolant will drain out of the thermo hole.
The job shouldn't take more than a few hours, and only requires a small torx driver, a 10mm socket, and a pair of pliers (channel locks are helpful.)

 

So you're just saying to let the coolant spill onto the ground? I was only going to catch the coolant so as to not pollute, and only reuse it if I could find a way to catch it straight from a hose (since it is only 3-4week old fluid). I'll be doing the swap on a gravel/dirt driveway so my initial thought was to just let it drain out and replace what I lose; since the MINI's so low to the ground, no one will see me polluting and not even attempting to catch the coolant. I figured the OP in How-To post did way more work than necessary for me; he did that thread on an S, mine is a non-S and it's very easy to get to (will probably just have to remove the airbox and that's it to access the thermostat housing).

Here's my plan of attack:

Remove airbox or whatever else is necessary to get to thermostat/housing. Remove bolts holding thermostat housing on, pull out thermostat/housing and let whatever coolant spills just spill onto the ground.

Install new thermostat with new gasket (Dad suggested I add a little permatrex create-a-gasket for extra protection), swap hoses to new thermostat housing and button everything back up.

Start engine with bleeder screws open a little to let air bubbles get out of lines (close once steady flow of liquid starts coming out).

Turn off engine, check coolant:water ratio and top off fluids as necessary, let cool, check fluids again. Done.

Am I missing something?

 

The thermostat on the R50 is in the same place as the R53, but it looks like you have less stuff in the way (primarily, the MAP sensor.)
There won't be much coolant that spills, but you can certainly put a small pan under the car if you want. From the link below, you may want to drain your overflow tank - on the R53 it didn't seem to matter.
I would not put any permatex on the gasket. The gasket is some form of silicone, so it's not like the old paper gaskets that can use the ptex to seal the surfaces. The gasket compresses and flexes when you tighten down the housing.
Other than that, sounds like you've got the right plan.

FYI, found this link to a description of doing the R50 thermostat.

 

I just got finished cleaning up from the swap this morning. Took me about 1 hour 45 minutes to do the entire thing start to finish.

My process:

Removed Airbox
Removed Battery
Disconnect hose clamps on Thermostat Housing
Remove thermostat housing, gasket and thermostat. My thermostat gasket was the old
white style.
Used a towel to clean up the engine block, and a little sandpaper to remove some built
up corrosion around the gasket mating surface
Hook up hoses to thermostat housing
Reinstall new thermostat/gasket and mount housing to block
Replace airbox and battery box
Fill reservoir with coolant/water mix
Turn on engine, let warm up with the two bleeder screws on the the radiator hoses
open. When I started receiving fluid out of the back one (below power steering
reservoir) I closed it. Never really got fluid to come out of the left most bleeder
valve.
Let engine cool and watch it suck coolant into the system, over time.

I'm still keeping a gallon of coolant and distilled water in my trunk for a while until the coolant level starts to stabilize. But for the time being, I'm just watching it very closely and marking the coolant reservoir where the level is when I check it. I'll be driving it down to town tonight, then coming home so I'll check it when I get home and hopefully in the morning it is stabilized mostly.

To know if the system is completely closed now, will I see the coolant reservoir level lower when hot and then increase when cold? Or is it the other way around?

Wondering how many days I need to monitor it before I can say for sure that the system has stabilized. Hoping it's not long though, having to worry about it while I'm driving to/from work or into town is a pain.

Overall, it went very smoothly and was definitely worth it to NOT drive it 2 hours to the MINI dealership, and pay them $472 in labor to do the same thing I just did. Especially since it only took me 2 hours from start to finish!

 

Just a couple of trips and you should be fine. I usually keep a small water bottle full of distilled water in the boot. If you need it for the coolant system, you've got it. And if not, you've got a bottle of water.
Glad to hear it went smoothly for you!

 

Well, after 3, 32 mile round trips and the coolant holding it dropped again from last nights 32 mile drive to this morning. I'm wondering if I didn't quite bleed the system properly or if there are still air bubbles in it.

I checked the coolant level this morning (when coolant was 17*C) about a minute or two after starting the engine, and it was about an inch lower than it was late last night when I checked it (and the coolant was at 31*C).

Perhaps before I leave work today (after car cools all day), I'll park on an upwards incline with nose up, remove the radiator cap and start the car. I'll slowly add antifreeze/water until the engine gets hot, then close the radiator cap and top off the overflow tank.

Not sure where to check next if this doesn't do it, I'm not seeing any signs of leaks anywhere, no puddles of coolant or drops on the pavement (currently 60*F outside, won't get much warmer than 75*F).

Even though the white/clear overflow tank is not leaking (no signs of leaking on the metal heat shield below it), I may just replace the overflow tank with the new yellow style. When I do that, I'll add a metal hose clamp to the hose at the inlet for the overflow tank just in case.

Gotta admit though that I'm starting to get a little worried about what else it could be.




edit: Looked closer just now and found coolant leaking out from between the hoses and the plastic H-bracket that holds the bleeder valve in the back, closer to the driver (not the one on the front left of the engine). Will buy some screw-style hose clamps tonight or tomorrow and swap them out, but 98% sure now that this is the problem. Found it odd that the coolant leaked out after surviving several trips where the engine got fully hot and cooled down all the way, but I guess the system could be under actual pressure now with no leak, and the hose clamps just weakened enough to let a leak form.

However, this leads me to believe that it might not have been the thermostat gasket to begin with, but just these hose clamps. The hoses themselves are just fine, no signs of cracking anywhere. But, at least I have the peace of mind now that the thermostat and gasket have been replaced, so I won't have problems down the line.

 

I've been wondering about this for a while now. Been noticing little wet spots all over my driveway and have finally come to same conclusion. The links above are very helpful and I now know what I'm doing this weekend.

 

Mine was definitely leaking at the thermostat gasket, when I removed it, it was the old white version and completely flush with the surface of the thermostat housing, so there was no extra gasket material to be compressed.

After driving home yesterday, I looked for leaks around those hoses and didn't see anything. I let it cool off about an hour and checked the radiator cap, it was full to the top with coolant, so I think the system is just bleeding air bubbles which is why it's sucking extra coolant in. I can't find ANY leaks now whatsoever, and last night I only lost a few millimeters of coolant (which is less than the night before, so I think it's finally starting to level out. I'm keeping track of how much it loses and should see it level out soon.

 

I had my thermostat replaced about 24K ago and 2 1/2 years and now I found a few spots on the driveway. Wiped clean and drove car pretty hard, temp was normal and checked no leak?? I am assuming its the thermostat again. Resovoir is proper level......just curious if the water pump went out what I be seeing?

 

Just looked at my car today thinking it was the T-Stat what I saw gave me pause. After taking off the intercooler cover air box/ecu I carefully looked around at the housing. The top "kind of looked like there was some seepage but the button and the top of the bell housing looked very clean regarding coolant spills.

while looking at the back (right side towards the firewall) I saw a bead of coolant below the exhaust manifold where I think the head is meeting the block. I wiped it up thinking I dripped it when topping off and before my eyes it returned. So I am hoping it is a head gasket leak. I have no white smoke, no milky oil so I am at a loss to comprehend this.

 

Hi there,

I just got a Mini 2 days ago and spotted some wet spots in my driveway today :( I checked the coolant and it was completely empty so I've topped this up to see how long that lasts.

I don't know much about cars and just wanted to ask what area of the car did you guys experience leaking from? Mine started leaking from the bottom of the front bumper in the middle, about 2 hours later it was leak heavier (as there were bigger wet spots on the ground) from the drivers side of the bumper (right side as I'm in Ireland). on this side it seems to be coming down on the black trim at the bottom of the bumper at the front as well as from the flat bit underneath.

I'm really shocked because my uncle who's a mechanic checked the car out up on his ramp 4 days ago and didn't spot this - is it the kind of thing that you wouldn't see from underneath?

Any help would be much appreciated - i'm hoping its the same problem you guys have experienced and its not more serious.

Thanks - Debbie

 

hello Debbie

did you by your car from a dealer or a private seller?

If dealer bring the car back and tell them they need to fix it.

- check the oil and make sure it is clean, full, and not milky or chalky. Milky/chalky oil could indicate a head gasket leak.

- Check the hoses that you can see while the car is running if you see steam or fluid it is leaking from the hose.

- Next check the thermostat 2005 to 2007 have a high incidence of the seals going out. replacing it solves the issue

-water pump when they go out they start to leak through a weep hole in the bottom. access to it on a mini is hard.

-radiator could have a hole or crack.

If you pressure test your system you can safely check for where the fluid is coming out I would guess it is the t-stat just because it is so common but that is just a guess.

remember when you fill use premixed coolant or mix with distilled water as the minerals in tap water are not great for the system.

good luck.

PS If it is a head gasket and it is a car from a private seller they likely knew it was problem when they unloaded the car. a check of the oil on private sales is an easy way to ensure you are not buying a big problem.

 

My coolant leak was a result of a water pump issue AND the thermostat. NOT a cheap fix if you are not mechanically inclined. Getting tired of being sent to the poor house by this car - brakes, clutch, coolant leak and valve gasket all replaced this year - 2007 with 65 k miles. WTF?!!!