Received my '06 MCS in Nov 06. First year was uneventful. When I was driving away from my first full service in January 08 it blew coolant. No repair was accomplished.

In March it blew again, out of town so a different dealer looked at it. They claimed that the first dealer must not have bled the system properly so again no repair was accomplished.

Later in March (during AMVIV) it blew again. This time the dealer said it was the thermostat.

In June it blew yet again. This time the dealer said it was the thermostat housing.

Last Friday enroute to MTTS it blew for a 5th time.

This time the SA told me that they found that the coolant reservoir cap was bad and replaced it. They drove it; seems good. Verified with the MINIUSA field rep (via phone) and the local BMW service shop. They’re convinced…but then again they were the last two times as well.

I’m having a difficult time buying this. First, a coworker has a degree in automotive engineering (and has basically rebuilt his Rabbit GTI Turbo power plant from scratch) and says that with today’s system, there’s almost no way for the pressure to get high enough to overcome those caps unless it was already hot.

But, assuming he’s wrong, here’s where I really struggle. Since March I’ve had a thermostat fail, a thermostat housing fail, and now a cap. Statistically, that’s in the land of the near-impossible. My SA refuses to even acknowledge the possibility that something else may be causing the coolant to flash and the thermostat, thermostat housing, and coolant cap are victims of that rather than the cause.

That said, I’m at a loss of what to do next, short of paying my mechanic (for my other cars) to take a look at it.

Thoughts?

 

The thermostat & thermostat housing are known issues. I've had them fail also. I've heard of bad reservoirs, but not of bad caps, although it is quite possible.

I know your lights are a fairly new addition, but I'm sure they aren't helping your car stay cool. You have a lot of the radiator intake covered with those lights.

 

So have they completly drained and refilled the system yet?

It would not hurt to take the lights off to test.

 

Everyone fixates on the lights (and I can't blame them), but the first three overheats occurred before I installed the lights. Somebody (forget who/where) posted that folks have raced their cars (i.e. high engine temps) with the same lights and noticed no temp issues...that's why I felt like buying them was low risk.

Car was "fixed" and test driven. They wanted to do check something after it had cooled down so they are keeping it overnight.

MINUSA has agreed to send the field rep to the dealer and have me bring it back in then for him to look over.

 

I don't have any ideas to add on the fix but you should document the history very well because this many overheats could cause head gasket problems in the future. The expansion in an overheat is abnormal and you don't want to get a couple of years down the road and have the head gasket fail from this.
Good luck with finding the fix.

 

Agree...Already insisted that the dealer run a compression test.

 

it has been noted here that though the system is pressurized and closed ; there is still a vented cap in place . if this were to fail to vent and your pressure were to exceed this 16lb. cap then i guess you could expell coolant . yeah? has it popped since the new cap?

 

Update.

Dealer called and said it was ready for pickup. Dropped off rental, got in my car (after grumbling that I didn't think the cap was the problem but rather a victim) and drove away. 6.3 miles later it (and I) blew its top again. I let it cool, added coolant (glad I asked for the dealer to put a jug of premixed coolant in my car) and nursed it back to the dealer.

I can't begin to describe my anger right now.

First, the SA and the MINI engineer both suggest that it's my driving lights blocking the lower radiator that's the culprit. Yet the first three overheats occurred before they were installed. Not only that, but they happened in relatively cool weather at highway speeds (lots of airflow). Heck, the second one happened in Salt Lake City on my way home from a ski trip. There was snow on the ground. Can't blame the Vegas heat or my lights on that one.

Then he says that my 15% pulley might have to come out because it makes the water pump spin faster. Huh? Isn't the WP driven by the crank pulley?

Some Googling by a coworker revealed that the OEM water pump has a plastic impeller. It's his experience (his degree is in automotive engineering...he's basically redesign and rebuilt his Rabbit GTI Turbo from the ground up to get 300 hp out of it) that these plastic impellers are on metal shafts and after a "thermal event" they tend to periodically expand and slip on the shaft, and the water flow stops. The dealer made no mention of even inspecting the water pump after any of the six overheats,

I'll add that until I had my first full 10K service, the car ran great. On my way home that day, and at almost exactly the same spot on the freeway as today, it blew the coolant for the first time. Ever since, nothing but repeats.

I'm convinced that all these small parts they're replacing are victims of an overheat, not the cause. Three (now maybe four...who knows) completely different parts break in the same subsystem and result in the exact same symptom...statistically that simply can't happen.

 

Sell it. I would. I love cars as much as the next guy (okay a bit more), but when material objects (like cars) begin to rule my life (and blood pressure), I neatly package them up, and move onto the next automotive experience.

Is there a wife/girlfriend in the picture? If so, I can't imagine she's not chewing your ear off to let the car go.

 

My wife has been eyeing a Clubman, but the inability of the local dealer to fix my problem has her rethinking that.

I'd love to get 2nd gen MINI but I have quite a bit of time and $ invested in this one...would rather get this one fixed than replace it.

Besides, I can't in good conscience sell it until it's fixed...and if that ever happens there'll be no reason to.

 

Sin. how long does it take for it to start getting hot. Do you have a temp guage from C-H or temp. let it run for a while. Feell the top of the Valve cover see if it feels hot compared to the rest of the engine. Do you have
a infared temp sensor. To point @ the engine. We had a cooper S the other day @ the shop. Found water was not circulating. Engine temp showed hot
but the acutal engine itself in certain spots were not as hot. We found a faulty waterpump. It runs off the Supercharger impeller. Also. I wonder if the correct stage on your engine fan are coming on. Sounds like a flow problem
if the radiator is not flowing and not getting hot because of cold spots
then the Aux fan Won't properly turn on when its supposed to. then in turn ,causing it geyser out the top.

Does your fan come on? there are different stages according to engine load.
check your fuses 1-5 and check fuse 8.

something is up investigate these items get back to me .


Guido.

 

Oh man,

I greatly feel your pain...
I myself am having a similar issue... my batmobile started heating up a few week's ago, but I never saw a wetspot or leak under the car, so the water is going somewhere... Finally get the time to check it out, remove the front end, WOW... the entire front of my brand new built motor freshly painted black to repel rust, is orange, rust colored... So I'm guessing it's the water inlet coming from the WP where the neck meets the housing of the block... this is how it get's water... So I pull the SC and alternator to gain access... both o-rings are shot... found the problem right? Replace the o-ring's... $5 and some change... put it all back together, fill it up, and purge the system for air... run's great for about 4 days and never overheats even at idle....

Today I notice as I walk up to my buddies door... my fan kicks on... I'm thinkin' CRAP.... run back to my car and watch the temp gauge just in case something decides to heat up... doesn't... I walk away as the fan slow's down... than I look back a few second's later... she's drippin' water from the block... dammit... go back, gauge starts to rise so I kill it... check the resivoir, dry again... wut the hell???

The car has 83k on it... I know the SC usually goes around 100k give or take... what about the WP? Could it be bad or have a broken impeller causing the car to overheat and melt the o-ring on the inlet causing coolant to leak from the inlet housing???

 

No pattern. Last Friday, took 45 minutes. Today (and the first time), 6.3 miles. At AMVIV, I drove it all day to Death Valley and back, and overheated when I was returning to the track in Pahrump because I had forgotten something.

Only the stock idiot needle.

Nope.
Please explain...hows does the SC drive the WP?

That's pretty much what happens...everything is normal and then...it's not. Sometimes it appears that the coolant came out the reservoir because it's all over the engine bay. Another time it didn't (probably the time the thermostat housing gave and leaked it out the bottom)

Fan appears to be operating normally...at least it's always running when I shut off.

Cooling systems aren't that complicated...either the WP, the thermostat, or a leak somewhere. Note I never find any fluid anywhere except after such an event.

 

The WP runs on the same shaft as the SC...

 

Wow, I never would have guessed that.

So, can a reduced SC pulley cause the water pump to fail? I guess it's possible. What size is the JCW pulley and does it use the same SC and WP as the MCS?

 

Its has special topsecret "coated" rotors... but yes, same SC... it does run a 15% pulley on the JCW... and no, this wont cause your WP to fail.... maybe it just went out? Im starting to think thats what mine did... need to get Guido back in here.... WAKE UP!!!

 

This seems like a real strong possibility.
I have had other plastic parts melt from overheats, heater valve, so even with the impeller designed to work in hot water is could have deformed or be slipping.

 

i'm having similar issues with my Cooper. '06 55k miles. mysterious empty reservoir every 3 days. they replaced the thermostat and the gasket for $225. this morning (the third time it has drained since) the cap was off of the reservoir, however i doubt it spilled out through there since it was pretty clean around that area. the wp is my next guess. and bmw is notorious for their faulty plastic impellar designs. ask anyone with a 3 series with 80k miles or more.

 

It gets ridiculously hot under the R53's bonnet. I thought my Corrado ran hot, but the R53's really cook. Strangely enough, they both share one thing in common, form before function. But I digress...

On earlier BMW M50 engines (E36 M3 for instance), the water pump used a plastic impeller. If equipped, this impeller will definitely develop cracks around the water pump shaft causing the impeller to disengage from the water pump shaft. The fix? An upgraded water pump with a metal style impeller is needed to correct this problem. That's not to say this is the definite cause of your failures. But since your tech buddy mentioned this, and as we know MINI = BMW, it's worth investigating.

 

Well I think I'm gonna pull my WP/SC again today and check the o-ring's... if they are cooked... than it's gotta be the WP... I'll post up something if I find out anything....

 

Update #2. After my car overheated on the way home, they were able to duplicate it in the shop (driving or idle, I know know). End result was 2 overheats since the last repair. They searched and found nothing broken, so they started pulling things apart. Water pump looked good, so they put everything back together...except the lights. Tested car with clear lower grill. Guess what. It overheated again. So at least it proved I was right and it wasn't the lights.

Now they are suspecting the fan. The fan has always run a while after an "incident" but they're thinking now that the lower stage must be intermittent and when it decides to stop the car overheats faster than the second stage can kick in and cool it.

 

Quite puzzling. Keep us posted.

 

jees this sucks . they do a full on flush?

 

Flush...I've no idea. Didn't think to ask. But given they pulled the water pump and probably the thermostat I'm sure they've replaced a significant portion if not all the coolant. My question is, did they inspect the old coolant for metal flakes that could indicate something internally has failed or could be blocking the flow.

 

Odd question, but what's your oil look like? It's not milky or foamy is it?