Thanks to the original poster! But I need help! I have changed my thermostat but the coolant will not fill the top rad hose and my cooling fan never comes on. The coolant in the expansion tank gets really hot. And my AC isn't working either. Big bummer. I was going to be selling the car and sold my Bentley manual already. Luckily this was here. Any ideas on what's going on would be greatly appreciated. The fuses I can visually inspect all look good but the box fuses (not sure what type they are) that I can't visually inspect, haven't been tested. TIA!!!

 

So I am lost and any advice would be much appreciated. I changed the thermostat and the housing, I knew I needed to but I'm getting ready to seek the car so I had to. My AC also isn't working so I was hoping based on some threads that the stat could magically fix that also. I followed this how to step by step and when finished I top off the coolant and it drips out of the bleed screw as it should, so I close it. Start the motor and let the engine warm up and nothing comes from the bleed screw when I reopen it. As the engine warms up, the coolant just overflows from the expansion tank and nothing goes to the radiator until the engine is off! What is going on here? Why does coolant circulate with the engine off, but no on? Please help, I would like to fix my MINI to get some drives in and be able to sell it in good working order. TIA!

 

Coolant doesn't flow, by the water pump at least, with the engine stopped.

It sounds to me like the Tstat is installed the wrong way around. Are you sure it's right?

 

So I redid the installation. Everything is in correctly. When the engine is off the thermostat is open and when I open the bleed screw, coolant will seep out of the upper hose, so I close the screw. Once I turn the engine on the thermostat closes, and if I open the bleed screw, the coolant that was in that hose passes the water pump and refills the expansion tank. I've run the engine until the thermometer on the dash shows its in the middle, but the expansion tank stays full and eventually overflows with super hot coolant. My radiator fan never comes on and when I turn the engine off I can hear the thermostat being reopened. Some body please help. I am so lost on this one. What should I check? Please please please...

 

So the T stat is turned with the spring into the head ?




You might not have a hose hooked up right or something, did you bleed the system a couple times?

 

Yes it is in that way. I've tried to bleed a few times to no avail. Same thing happens every time.

 

The thermostat is temperature operated. When cold the thermostat is *closed* to keep water in the engine until it warms up. It then opens as it heats up. OEM is designed to open at 180deg. I don't know what you're hearing, but I doubt you can hear the t-stat open and close.
Is the overflow tank closed when it's spewing water? The system is design to be under pressure, so the cap should be closed.
If low speed fan doesn't come on and AC doesn't work, your low speed fan resistor is probably dead, which can lead to the failure of the AC compressor.