My poor MINI has developed an overheating problem that I'm hoping someone can help me diagnoce. I've searched the forum and come up with similar things but nothing exactly the same. So here's my story:

The car sat for a few weeks before the issue started. When I got home from dinner one day the fan continued to run after parking (which hasn't ever happened, even during the summer). I noticed that the coolant reservoir was empty which lead me to believe that I had a leak (I park in a driveway and never noticed a leak so I was concerned that it might be leaking into the engine, but never say any signs of a change in the exhaust or any smells). I am also meticulous about the car so I would have noticed any leaks in the driveway. I refilled the reservoir to try and find the leak and took the car for a drive. The car got a little hotter than normal, and again the fan ran after the car was turned off but stopped once the temperature cooled to the normal temp. I checked, but haddent lost any more coolant. I ran it again, but this time, while coming up a hill, the temp really started to climb. On top of that, the heater stopped blowing hot air (its winter so it was running the whole time). The car came very close to overheating by the time I got home and the fan ran until the car cooled to normal. Again no loss of coolant and seemingly no air pockets in the system.

I've seen posts about the fans running due to issues with relays or the fan, but since it does turn off its seems unlikly that it would be a fan issue. What really puzzles me is why I lost hot air out of the heater and its still overheating. I've seen some postings about the water pumps coming apart because they are plastic. I really hope that I don't have plastic bits flating in my cooling system plugging it up.

Thanks for any insights.

 

Year....
S or non s?
the fact the coolant ran low...
And you have no heat kinda makes me think you got air in the system...and it needs to be bleed...the mini usually does not selfbleed just by adding coolant....the reason you are low could be numerous...many leaks are so small, drips rarely occur.

 

I had an issue with my 2006 s/cab a while back. The coolant was fine but it would still overheat whenever I was idle. Ironically it would cool back down once the vehicle was in motion so I pretty much tried to keep it on highways or long stretches of road. I don't know exctly what your problem is but my problem was that there was a leak in the coolant line. My vehicle was still under warranty at the time so the fix was free so I couldnt tell you how much it would cost if you went out of pocket.

 

ZippyNH: its a 2006 non-s which is unfortunately out of warranty. Thanks for the info. I though figured it would self bleed like my blazer. I'll have to try and bleed the system to see what happens.

O how I wish I was still under warranty.

 

If your coolant level went low enough, there might be a lot of air in the system... so much that it starved the heater core of coolant to warm it up... hence no warm air.

So bleed the system a few times. Do a search for tips as it's a bit tricky to bleed the Mini cooling system.

Another culprit is a dead thermostat will not allow coolant to be circulated through the radiator and causes overheating. When the fan is on, check if the radiator is hot. If it's not, and the system is well-bled, you've got a stuck thermostat in the closed position. However, a stuck thermostat with coolant at the correct level should still have working heater.

 

I know s mini centric shop that uses a vacume attatchement on the overflow bottle on the non s....
the arrangement of the tank makes gravity bleeding to hard.
Always check the simple and cheap stuff first...since you ran low on fluid, and an airbubble can cause all your issues (except the slow coolant loss), bleed it.

Failed water pump, stuck thermostat, etc is all possible....but pretty easy to check for when you do the bleeding...prettybasic checks.

 

I think the R50 is pretty easy to bleed. There is a plastic cap on the upper radiator hose which you can remove to let the air out.