Three times now over the last several weeks I've had to add 8 - 16 ounces of antifreeze to our '06 MCS (25,000 miles) to bring the level back to within the MIN/MAX lines when the car is cold. No visible leaks or puddles anywhere and oil color looks normal/level is fine. What's the next step? Pressure test by dealer? Is this normal antifreeze loss? I've never had another vehicle "use" this much antifreeze except for an '06 base cooper company car that lost small amounts of antifreeze too. Puzzled.
Greg

 

My first thought is the water pump seal. It's been noted on here before as a common leak area. It happened to me a couple years back. Eventually, it got to the point of leaving a little puddle under the car every morning. Usually, it leaks so little that it just evaporates before it hits the ground. A $1 part but several hundred in labor for a dealer repair if out of warranty.

 

You may want to take a close look under the car where you park it, you may notice a small stain or two on the ground. The pump housing seals fail on this car, usually a warranty fix. I have an 06 as well, happened to me last month.
Take it in if it's still under warranty and ***** til they fix it.

 

I had a small leak around the thermostat housing on my '06 - only 4-6 ounces every week or so. I took it in to the dealer and they couldn't find any signs of leakage, but since it was a three-hour round trip for me, I asked them to park it out of the way for a while with some cardboard under the engine. Sure enough, as the car started to cool off, coolant started dripping out, so they replaced the thermostat and housing under warranty.

 

My wifes 05 MCS (built 8-05) had the overnight drip in October '07 and was repaired under warranty(thermostat and housing). It had the same type of situation a week ago, so I spent about an hour dis-assembling the car to find the leak. The seal for the thermostat was split, so I spent $125 for new parts and 3 hours carefully cleaning and re-assembling to stop the drip(out of warranty). When we were at MITM last year, our friends MCS Cabrio pewked in her parking spot. Luckily, it was under warranty and the dealer came out to fix it. Unfortunately, its not a recall item. They just fix 'em as they break!

 

Thanks for the posts! I will try the cardboard and see what comes.
Greg

 

I have the same problem... what type of coolant should I use? Will any type do?

 

Zerex G05 is as close as you can get to OEM coolant

 

Yep, Zerex G05. good stuff

 

The thermostat housing is known to warp and leak over time. Search for a 5+ page thread on the topic. It is covered under warranty.

If all you need to do is top off a slow leak, water will do until you get the problem fixed. Preferably distilled water.

 

2006 MCS - Anybody have a picture of the radiator cap? NOT the coolant cap - that I can find. Might be hidden within plain view, but when I went snooping around for it, I haven't seen it yet? Is it tucked underneath the shroud?
Thanks
Greg

 

On the Mini and most European cars, the coolant tank cap is the radiator cap; that's why it's under pressure.

The design you're thinking of are mostly on Japanese / US cars where there's a radiator cap and a separate reserve tank to collect overfilled coolant. The reserve tank has no pressure.

 

Can you mix OEM coolant with Zerex G-05 (ie top-off) or must the OEM coolant be evacuated first?

 

+1 If you look inside the coolant tank near the firewall with the engine running (don't try this with a hot engine, obviously), you'll see that there's coolant constantly flowing through the tank - it's not a typical expansion tank like in American cars where coolant only goes into the tank after it's heated up and expanded beyond the capacity of the radiator.

On a related note, this is also why you can tap a hole into the firewall tank to mount a coolant temperature sensor, which you can't do with a regular expansion tank.

 

mine's got the same problem. just use distilled water if you are going to have it fixed soon. Or prestone 50/50, i couldn't find the zerex and will not pay the price at the dealer for it.

 

Got it! Thanks! Greg

 

After driving the car for 20 minutes and placing cardboard underneath revealed a leak (blue/green liquid) pretty much underneath the center of the engine. As best I can tell, the plastic coolant tank cap, seam, and hose connections to it are not leaking, but not sure exactly where it's originating.
Greg

 

More than likely it is the thermostat housing that is leaking. It is a very common occurrence on our cars. If you still are under warranty get it in & have it fixed. If not get it fixed anyway.

 

It is still under warranty - 25,000 miles. Few questions:
1. If it is the thermostat housing, will they replace the thermostat at the same time (or should I have them replace it at the same time anyways?)
2. Will the entire system get flushed as part of this repair? I remember this being a 3rd year "normal" service while the brake fluid is changed every two years (but I may be wrong)?
Thanks!
Greg

 

Just bought my '06 Mini a month ago, service records show it also had the thermostat housing leak. At about about 20 months from the date of purchase, the dealer replaced the thermostat, the flange (housing), topped off coolant and pressure tested the system.

If you're still under "free" maintenance, I would press them to flush the cooling system and replace with new coolant.

 

When my housing was leaking, I got a new housing, thermostat, and related gaskets/seals. They topped off my coolant, but I don't think they did a full flush/replace.

You can ask the dealer to do a full flush, but I think the specified interval is four years, not three, so they may decline. You're correct that the interval for the brake fluid is two years, though.

 

They replaced the housing, gasket & thermostat. Coolant was topped up. Since you are at 3 years I'd ask that they drain & refill the coolant. Since they are working on the cooling system anyway.

I was told that MINI includes 1 gallon of coolant along with the parts for this job. IMO most techs would only add what coolant was lost during the fix, which isn't very much.

 

Hey Folks,

2006 MCS is repaired - I was told they replaced the thermostat, so sounds like it was the thermostat housing leaking as predicted by several.

Other item: I was told the tires are @ 4mm and 5mm front to rear, respectively; brake pads are @ 9mm, and that those specs are AOK. The car currently has ~ 25,000 miles on it.

Question now is: At what mm should brake pads be replaced and any guestimates on mileage we should expect given current wear.

Thanks!
Greg

 

I wonder what percentage of Minis have warped heads as the result of leaky thermostat housing.

9mm is not bad. Depending how you use the brakes and your driving environment, 9mm can last 15-20k if you do mostly freeway driving. Mini has brake wear sensors so a warning light will let you know when to replace pads and rotors.

The sweep area of the pads are small for the rotor diameter, which brings the customers back to the dealers more often. The first owner had the factory-issued front pads replaced at 26k. My New Beetle front pads already has 80k and I expect them to last till 100k. The rear pads' going rate is about 50k. For a daily commuter car in SoCal, that ain't bad.