Hi All
I have had a long history with this code, I have replaced the Coolant Temp Sensor, and the fan will run even one occasion when I only drove a mile and a half. This code occurs whenever the fan runs after I drive the car and shut it off. Up 'til now, I never hang around to see how long it will run. I clear the code and the fan shuts off. My scanner real-time data temps report low, e.g. 164, 139...The code shows up in Bimmerlink, and a cheap plug-in reader with an LCD screen (which is faster). I was vacillating whether to replace the thermostat myself or take it in.
I won't go into granular detail, but A buddy convinced me to take it to a reputable shop, which I did, and they told me that they scanned it and could not find anything wrong with the car. The Manager drove the car, then had one of his Tech's drive it. Their shop is fully equipped with factory diagnostics.
What brings me to the forum today is to ask for folks to chime in. I'm not disputing the shop, It's the suspension of disbelief. I don't get a CEL when this happens.
I expect you will have questions. My buddy said forget about the code. Drive it, shut it off and hang out and see how long the fan runs. My concern is the first time this started, it flattened the battery bc I did a scan and went in and researched it while the fan continued to run without me knowing, so if I pull up and the fan is running and I pull a P0128, I clear it right away.
Thanks in advance for your help.

 

P0128 Means the thermostat has given up, and is now stuck open. When that happened on my car, the CEL will not illuminate on every drive. I would start making plans for changing out the thermostat.

 

Nik
Thanks for your insight. Believe me I believe you! I've been dealing with this since December of 2024. Thanks to all on the forum for experience and guidance. Side note: My buddy George, who is a consummate car guy, and a friend of over fifty years had taken his son to the train station. You can see the shop from the platform, so he went and inquired about my car.
The Manager quoted him $800-850 for a thermostat job, so I made an appointment. Last quote I got from a German Auto shop near me was $1200.00. When I got to the shop he told me $900. I said "you told George 8-850" an he said "I'll do it for 8 flat". Maybe he's trying to wiggle out of the job.
I spoke to George yesterday and he told me forget about the code and drive the car home and see how long the fan runs. I am picking up the car today and will ask if the fan was running after the drives, and for how long. I have to pay $180 for diagnostics. Prior to this, George out of the blue told me he would split the cost with me. He's a classy guy and drives a Maserati Quadroporte. So I was going to shop some of the recommended Mini shops in my area and then this happened.
Will post results.
Regards

 

$800 is a bunch of money still. If you are mechanically able, its not a difficult job, apart from removing the cross pipe clip. Good thing is you don't have to reinstall the clip after swapping the thermostat.

I just checked your profile, and see that you already tried replacing the temp sensor:
https://www.northamericanmotoring.co...p-aligned.html

Remove a few more hoses and clamps, and you can get the thermostat out.

 

Thanks Nik
Good to hear you do not have to replace the clip. Should the pipe be replaced with the thermostat?
I was currently thinking when I would have time to take the car offline and attempt it. I've been working on my cars since 1970, but not as sharp these days as I used to be. Last thing I want is to have a shop salivating as I am towed in.
From what I have read, the pipe clip is a tricky part, and don't want to bust the pipe.

 

If your pipe isn't leaking, leave it alone. I ran my car over 200k miles on the original pipe, and I replaced my thermostat twice, and water pump once.

 

No coolant leaks whatever. Last time the thermostat was replaced was in May of 2021, right when I bought the car, I drove it home and got a CEL on the way. My Dealer took care of it, pipe included.

 

I went to pick up the car and upon arriving, my car was parked outside the shop with the fan running. I went in and said "the fan is running". He said "I know" They did another test and scan and the code appeared. They are replacing the thermostat today and I will pick it up tomorrow.
Thanks Nik.