mini one - heating issues

[laurabond2002]

for a while now, i've had issues with my heating, eventually a garage diagnosed the head gasket had gone. I've had this replaced, all was well. Then a few weeks later, I wasn't getting any hot air out of the blowers. took it back to garage, found it was air locks, fixed & had hot air again. few weeks later, same thing again, air locks, garage fixed & hot air again. Inbetween all this, we were checking coolant level daily and then weekly till it settled.

It's been ok for a few months and now the cold weather has kicked in, suddenly no hot air again. We bled the system by undoing the 2 screws we could see, lots of air released. once all gone I took the car for a drive, after about 10mins, I finally started getting hot air, but when i got to a junction, the air would go cool, as i pulled away and got up to speed, the air would go hot again?? When we got back home, left the engine running and eventually it was just cold air coming out. I undid bleed valves, lots of air in system again and didnt tighten untill all air had gone. sat back in car, still blowing cold air, despite engine being at temperture.

Next morning, i removed air from system via bleed valves, then removed coolant filler cap. started the engine and waited for it to warm up, when engine got to temp, i could see lots of bubbling in the filler tube till eventually just water was coming out. I took car for longer run, and despite been up at temperture before setting off, it was still a good 10mins till hot air started blowing out, but as above, when got to junctions and eventually end of journey, back to cool air? I undid the bleed valves and again, lots of steam being released for a good minute until coolant started coming out. The final notes to add is that one side of radiator is always hot, as I bleed air out of the system, you can feel the other side of radiator warming up? The cars temp always reaches midway, and doesn't appear to overheat. Not sure if it helps, but the header tank is always above the max level...whether this changes when driving..who knows? No coolant leaks either?

Does anyone have any ideas what might be the cause of this. Sorry it's a long explanation but want to get all the facts out to help diagnose this. when the garage replaced head gasket, they apparently tested the water pump and said all was well. Could it be the heater matrix, or is it simply still an air lock? Something else is a dodgy thermostat??

thanks in advance
stressed mini one owner (

[mab01uk]

Have a look through this link of Mini cooling info it may be of some help in pin pointing the possible causes:
Solving MINI Cooling Problems.......... - Forums

[laurabond2002]

Thanks for the reply. I've checked out the links and what I've just tried is bleeding system from cold, heating on, fan on full blast. Filler cap off, both bleed screws open. After 5mins the water started bubbling in the filler cap, occasionally coming to top then sinking back down, I kept squeezing the inlet hose to the radiator but at no point did any fluid come out of either bleed screw...would I be right in thinking the water pump isn't functioning?

[mab01uk]

This case in link below turned out to be the water pump impellor (inside) was not turning with the shaft/pulley and therefore not pumping water around the system properly.......no way of telling for sure without removing the pump to examine inside though:
http://www.mini2.com/forum/first-gen...nightmare.html

Not sure how your garage would have tested the water pump without removal?.......only leaks are really obvious from the outside.

[Triumph fan]

I was the poster in the thread referred to above,my daughters 2003 Cooper was overheating with the heater being stone cold,we had bubbling in the filler and i tried bleeding it loads of times.

I put a new rad and thermostat in as well but this didn`t cure it,i also cleaned out the heater matrix,while doing this i noticed the water was old and brown although the system was refilled numerous times,this seemed to point to the pump not circulating water properly.

The pump is mounted on the front of the engine and means dismantling the whole front to get at it,there is an excellent technical article on how to do this somewhere?

When i removed the pump it felt very loose.I don`t know how your garage tested the pump but i don`t see a way of checking its working on the car.
I fitted new pump and after putting the rad back in and refilling we instantly had warm air and no more overheating.It seems the pump had failed internally and although there were no leaks and nothing appeared to be broken it just was not pumping.

Cars been fine for about a month now and i keep checking the coolant level regularly.
Hope this helps.
Steve