This is with my Mini Cooper (non-S) Cabrio. The entire drivetrain is completely stock. The car is just over 1 year old.

This is a very strange issue that I'm really not sure what's causing. I am under warranty but the nearest MINI dealership is 150km away so I'm hoping it's nothing serious.

When I'm driving the heater works perfectly normally. Gets quite hot as the heater does. Now as soon as I'm at idle for about a minute, the heater starts blowing nothing but cold air. The fans still work, but no heat whatsoever.

What really concerns me though is that if I'm at idle for more than a couple minutes, the engine temp light creeps up all the way to the top bring the temp warning light on. The gauge goes back to normal (about halfway) within 30 seconds of resuming driving.

The first issue is more frustrating than anything but the second one quite worries me. I do assume they are related though.

Any ideas? I did a quick search on the forum but I could not find any related issues.

 

Do you have enough coolant?

 

To be honest I havn't checked the coolant yet. It is a closed system though isn't it?

 

Yes, but if you have a blown gasket or a leak then it could have gotten out somehow. I'd check coolant if you're overheating, once you eliminate that you can move on to the more complicated stuff .

 

Looks like you're right. It's very low. I'm borrowing a vehicle to get some anti-freeze now.

Thanks!

 

A word of caution, the MINI takes special antifreeze. You'd probably be better off filling it partially with distilled water until you can get some from the dealership. Some other's can chime in, but I've heard about issues with waterpump seals using anything other than the MINI Antifreeze. Perhaps give the dealership a call and ask for their advice?

 

I don't really have much choice as it certainly wouldn't be safe to drive 150km to get some and it still freezing where i live at night so distilled water is out of the question.

I put some anti-freeze in for now but I will call them tomorrow and try to figure out a solution. Obviously I still need to get it booked in for service to find and fix the leak, but for now the anti-freeze i put in seems to fix the issue.

 

If you have a BMW dealership closer their coolant should be the same (Or at least similar) .

 

Nope, the closest MINI dealership is also the closest BMW dealership.

 

Don't mean to start any wars over this, but for all of my (considerable) checking, I can't find any verifiable documented accounts of a compatible antifreeze causing harm to MINI waterpump seals (they are not unique in any way).
By compatible, I mean one of the name-brand Extended Life antifreezes. Brands in the US include Prestone, Xerex, or Peak, and will be labled Extended Life, Long Life, or Dex-Cool. Other than the color they are all (including MINI's) the same formula -phosphate, silicate, and borate free.
Buy the 50-50 mix and it's ready to pour in without having to add water.\
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Bad news. I took it for a drive and the same issue occured again. When I checked the fluid level after it was exactly as it was when I filled it so it doesn't appear to be leaking, or if it is it's very slowly and shouldn't be cause this problem.

Any other ideas? Should I be having my car towed to the dealership for warranty?

 

Perhaps thermostat or other is failing, making the car not heat up well and pressuring some location to cause a leak. Reason I say this is we have a 1997 VW with a 'weak' thermostat (sorta stuck open); car will heat up very slowly after miles on the road, not at idle so heater feels weak (no restriction of coolant to radiator making it overall cooler when it gets to your heater). In a different car, I saw a stuck closed thermostat over pressurize a radiator - nice steam show

Anyway, painful as it is I think MINI should pay for your tow and make your car right again. Cooling woes could take down the engine...

 

You might also have air in the system that needs to be bled out. Check around the thermostat housing as the '05 and '06 tend to develop a leak around there. My wife's '05 MCSa was dripping on the garage floor and it was from around the thermostat housing.

 

Forgive my ignorance, but where would i find the thermostat?

 

"The thermostat housing in the Cooper engine is part of the coolant filler neck at the rear of the engine." Bentley manual 170-9.
On the left side (your left as you face it) of the battery, you'll see the heavy red cable coming out. Directly in front of it (towards the front of the car) is a black cap with yellow lettering. It's at about 5 o'clock from the oil filler cap. That's the filler neck. Three bolts hold it on. It may help to pull the intake hose, and if you want to make life easy, the battery and battery box. Drain some coolant first, or it will get all over everything.
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maybe water pump; or belt which drives it is slipping .

 

I was able to get the coolant flowing so the heater is working properly again and it's not longer overheating but it's definitely still leaking. I have to add coolant daily.

Hopefully I can get it into the dealership ASAP.

 

This sounds like the classic thermostat problem. Thermostats are usually very easy to replace and inexpensive. The little gate in the thermostat is stuck and not directing hot water to the right places so that your heater will work. If so it is no big deal, but your engine won't regulate its heat well and could overheat unless you get it replaced.