Been reading through tons of post in the past few weeks and thought maybe its a good idea to reach out to the community for help.

Bought the car about 5 months ago, 3 months ago the CEL came on and threw out a P173B + P0128 code at the OBD port. We initially suspected a bad thermo housing ordered a new one from Mini and had it swapped out (local mechanic), bleed the system completely and re-fill. Code cleared the first day I drove it off and heat was working well, thought the problem was fixed. Fast forward a few days later and the heat stopped working and the CEL came back on with the same codes.

Engine coolant is maintained in the resv tank, levels are constant for the past 3 weeks.

Other symptoms include fan running for extended period of time after car is shut off.
Engine coolant temps never go higher 130-140 MAX (thats after 2 hours of stop and go traffic in NYC)
When driving in sports mode that little backfire that happens when the car downshifts as it slows down is not present and can not be duplicated.
Interior heating is not working properly, it's been freezing temps outside and heat is blowing mild hot air.
Pressure test passed before thermo housing was replaced and re-checked afterwards no issues.

Yesterday we re-bleed the system and noticed that the car is running the fan with or without the heat on, even if i start for a 30 seconds and shut off the extended period the fan runs for some time. Our next idea is to look into the radiator temp sensor (i have no idea if that even exists on a mini). I thought the temp sensor was built into the housing which was replaced 3 weeks ago, with a new wire harness as the new version needs it.

Any advise would be greatly appreciated.

 

Do not give up...Rebleed the system. while the car is running and full fan and heat, open the bleeder and let it spit out until you see a steady flow, then close it. of course keep an eye on the reservoir and fill it as it goes down.

my 08 MCS did the same and was about to cry :( i decided to do that (above advice) and heat was back in the cabin and all water lines were hot later on.

 

Thinking I am going to take it in tomorrow to the shop and have them bleed at the (2) or (3) different bleed points, all while refilling the resv tank... here comes my hail mary before I change anything else.

 

Bleeder is only in one place. a plastic screw next to the temp sensor.

 

I understood that there are 2 or 3 points that we can bleed from, not sure i read it somewhere on the forum.

 

Just the screw on the top and you have to fill the expansion tank, then close off and bleed it. I bled mine like three times to get all the air out. You have to have the heater on full heat to open up the heater core. Also make sure you dont have any other leaks, check out this thread for places to check. https://www.northamericanmotoring.co...8-no-heat.html

Thermostat diy and bleeding.

https://www.northamericanmotoring.co...hermostat.html

 

Thanks for the advice, I had LM bleed it and re-check the connections of the thermostat housing they put in. Seems as if the bleeding wasn't the problem it was a wire loose in the main harness, not sure which one yet going to see for myself.

 

Welcome. Ok they bumped a wire loose, as you can see by the DIY the main harness needs to be moved around some.

 

So my LM did some investigating work and discovered that under the engine manifold, on the left side of the car where the exhaust ties in there is a wiring harness that one of the wire shield was stripped away and touched the exhaust down pipe that was causing a short somewhere in the fan control module and he shielded it. He was able to clear the codes, and bring the engine temp up over 170 degrees where previously we were averaging only 120-130 degrees. Will drive it around for a few days and see if the problem persists.

Otherwise happy mini owner if the problem stays away.

 

So these dam codes dont want to stay away (P173B + P0128) both came back on saturday night after driving about 35-45 miles after clearing them the last time.

From the time i picked it up on thursday through friday the car was hitting 180-190 degree coolant temps, and the heat was great for the short period it was on. Just dropped it off by the LM again he wants a few days with the car, to be able to road test and diagnose the problem further.

On the checklist of completed things:

Coolant was emptied and flushed (3 timex to remove the old coolant)
New coolant levels have not gone down since it was last filled. (vacuum tested no leaks found)

Replaced thermo housing and updated wire harness from single to double plugs.
Bleed coolant multiple times since getting the CEL.

Anyone else want to chime in and throw up some advice or next steps we can take to make this all go away.



___________________________ EDIT _______________________________

Just got a call from the LM, he is thinking the thermostat that was replaced from the dealer is at fault for throwing the codes again, se he ordered a replacement of the replacement so does this count as 2 thermostats replaced? Wondering if anyone had any issues with the thermostat that was new from the BMW dealer.

 

So an update...

picked up yesterday, running nice all day for about 15miles. Today did another 25 and cel came back on and threw p0128 code again. My LM changed out of the internal sensors on the thermostat, not the entire housing.

Taking it back in, but he was talking something along the lines of reprogramming the ECU? OR POSSIBLY REPLACING THE ENTIRE UNIT Does this make sense? Costly?

Some other suggestions?

_____


Can anyone confirm if this post is actually true, my reasearch has not shown any sensonrt in the radiator house as per this response: https://www.northamericanmotoring.co...ml#post3852494

 

Happy to report that on the 3rd thermostat housing swap the car is finally able to achieve proper operating temperatures. It climbs pretty slowly but all in all its fixed. Hasn't thrown a code for a week or so. The fianl swap was an aftermarket thermostate inside an OEM housing that did the trick.

Happy to be motoring again and loving my mini until the next fix...

 

that is good news! thanks for the update

 

So here goes my rant...

This morning I remote started the car twice, first time the car was on for 10 minutes and shut off, so I was still not ready to go so I kicked it up again and started driving off about 2 minutes into the second warm up. The car was at 127 degrees for the engine coolant. After driving for about 25 minutes (10-12 miles) the car temp topped off at 138 degrees while driving on the highway.

Parked the car, and the fans were on full blast when I got out of the car, came back 20 minutes later the fans weren't on any longer and went to start the car threw up the CEL light. I had my Ancel plugged in and the temp of the car was readying around 144 degrees. I was not able to read a code, but after shutting off and turning the car back on the code reader was able to preform an erase on the code and it cleared the CEL light. (mind you I tried to scan it multiple times and it did not reply with a code).

Madea stop at a store had the car idling for about 25 minutes top temperature was 185 degrees. Got out ran my errands, came back started it up car temp was 155 and I was set to start driving off toward home base. Upon arriving I left the car idling for 5 minutes in my driveway while I unload the car. Drove to my office (20 minutes about 7 miles stop and go on the streets) temp was up to 190. Let car idle again on driveway for 20 minutes and temp hit 230, car fans turned up on HIGH setting from the sound of things and it brought the temps down to 185-189.

So far to date we swapped the thermostat housing twice, bleed it like a million times, swapped out the OEM thermostat with an aftermarket (which is currently installed). Coolant levels haven't seen any noticeable drops. Compression test on coolant system shows no leaks.

The next step, I am thinking of replacing the water pump, possible a flow of coolant issue?

Someone mentioned to me that the ECU should be re-programmed, i am not sure if this makes sense to do or not ($400-600 )

The temp outside is about 40 degrees in NYC today, wondering how long it takes your cars to heat up from cold start in the morning, if you let it sit idling and warming up for 10 minutes does the temp reach over 130 degrees? Is it common to motoring around town for 15-20 minutes and not reaching over 170 degrees for the coolant temps? Am I over thinking these points?

 

if you can come down to philly, I can reset adaptation on your car and also do a deep tissue scan on it.

 

Thanks for the offer, is this something I can preform locally, resetting the adaptation sounds like I need to plug it in to a BMW scanner.

Deep tissue scan sounds a lot more interesting... what does that entail?

 

It is more than a scanner that needs to be used. I acquired a delphi scanner like this one (https://www.totalcardiagnostics.com/.../delphi-ds150e) that pretty much can read most if not all modules in the car. you can trigger components for testing and read live data feeds.

 

So I am happy to report that its been 3 weeks and the thermostat is holding its own... for now.