I have a 2004 mini with about 55,000 miles , i live in Florida where most of the time its warm but if it gets colder then 50 i start having problem with the coolent system , levels are all ok but when its cold outside (dont happen that offten in florida) i will be driving and the temp gauge will go to max. i will stop the car and i check under the hood and find that the level in the over flow is all most over flowing well passed the max. all most like it has an airlock in the coolent system. But if its 65-98 outside the car is fine?????

 

wow no one has any idea what my problem is!!!

so i have try to do a few thing but still having same problem

replaced Radiator cap and changed out THERMOSTAT.


other then that i guess i just need to hope for warmer weather again and maybe post next year when it get cold again!!!

 

Did you bleed the cooling system? It could have a bubble.

 

yes i did bleed the system weeks before and i did it again after i changed the thermostat. please note this only happens when its cold out side had the same thing last year but was only cold down here for a few day and it went away. this year having a ton of cold weather.

starting to think it could be in some kind of bypass to the heating system for inside the car (if there is a bypass) if its cold tomarrow im going to not turn on the heat and see if anything changes

 

turning on the heat (given it's working right) would only help to pull heat off an overheating engine . i'm baffled . i can only think to get a hydrometer and check the coolants temp rating. overheating is less of an issue as temps drop unless ice is blocking something . doubt you got ice . check low speed fan operation maybe .

 

Is it possible the thermostat is installed backwards or something?!
A car that run fine when it is hot, but overheats when it is cold, but not so cold I can form to block the radiator is really odd!!
What else have you noticed? Does the fan run normally, is the radiator/hoses hot to the touch, any odd noises? Any strange matainance history with the car?

 

Fan running normal speed unless running hot then it run at a high speed and will stay on after car is turn off. all the hoses are hot to the touch, no odd noies. have had no problem with the car only this one when it get cold outside.

note on Herbie hind post the coolent in the over flow is very hot i dont have a hydrometer but put a meat thermometer its around 200F

 

get a hydrometer from an auto parts place. it tells you at what temp your coolant is good to . up here in north it is useful in seeing how cold till it freezes . is the car parked outside at night? has it been below freezing? i've had ice in gooseneck on a truck before and i can tell you it will overheat till it melts . get a hydrometer .

 

Just make sure you don't get a hygrometer by mistake!

 

Ok I got a though about this problem. If I had a hair line crack in the head gasket that is pumping air in to the coolant system and making a airlock. Because it is a very small hair line crack when it is cool out it open up and when its warmer out side the gasket is swelled up and not putting air in the coolant system????