Last week, my 'Engine Service Soon' light came on and i went to autozone and got a readout of the codes. What was pushed out was P0128: Coolant Temp Below Thermostat Regulating Temp.

It had 3 suggestions: Flush coolant, Thermostat broken, or coolant temp sensor broken. I already did a complete coolant flush and it made the light go away. YAY, right? No. The light came back on yesterday while i was driving.

Do you have guys have any insight of what i can do to take care of this myself ? Im guessing my next step is to replace the thermostat. Do you guys know what part i need and where i can get the part?

04 Mini Cooper

 

Probably the thermostat. They are designed to lock open at failure (sometimes it even works!). Stant makes a nice heavy duty one, part no. 29209, for around $12. Available at most autoparts stores. Or you can do the snobby thing and get an OEM one from a dealer or Pelican Parts. Your choice.

 

haha im not that snobby ;]

do you know where i can find instructions on how to replace it?

 

That come with a gasket too?

It's all but impossible to find directions for it specifically, basically drain the coolant (get a drain pan, undo the hose tot he radiator on the drivers side), pull the airbox, you'll see the housing (leave this connected to the hoses if at all possible, the clamps are a PITA) remove the 3? housing bolts pull out the old Tstat, replace with new one and new gasket, make sure the little valve is oriented properly (I'd have to double check just which way) and plug it all up refill your coolant, using the screws to bleed out the air (search these instructions are out there). And with an 04 you're likely due for a coolant flush anyways, so this is a good timing for you.

 

Thermostat or air in the coolant system.

 

Test out your coolant temp sensor. Remove the sensor and using a multimeter measure the resistance between the terminals. Hold on to the sensing portion and watch as the resistance values change. If they don't change, the sensor is bad. Most German cars are using 4-pin ECT sensors now, so if you're up to it I can try and get you the pin numbers.

Better to be sure of what it is than to throw a parts grenade at it

 

I had a coolant leak from my thermostat housing. Under the 100, 000 mile extended warranty, MINI replaced the housing and the thermostat and also performed the full flush. Apparently the thermostat is a pretty common failure. Good luck!

 

where can I go to get a new housing/gasket?