I changed my wife's R56 (non-S) coolant pipe and thermostat housing a couple of months ago. The thermostat was replaced with a REIN oe from FCPEURO, not a genuine BMW. No issues since then but this past week got a check engine light. I scanned the codes, and it was giving back fault 2F07 (Map Thermostat from DME). I reset the code with my Foxwell scan tool and tested the temps while driving around. I was getting between 156-172F while driving in traffic (30-40Mph) and on the highway. Prior to the work done with the original thermostat, I was getting temps all the way up to 210-220F which seems to be more normal based on all of the threads that I have read.

One thing that I also noticed was that when the engine is cold and I start it up, the AUX fan starts up immediately and it feels like the upper radiator hose has fluid flowing through it. The heater is somewhat warm at start. Based on this, I believe the thermostat may be stuck OPEN such that coolant flows to the radiator immediately. Does this seem correct?

The thing that puzzles me is that the temps are still very low when the engine has been driving around for quite some time. I would have thought even if the coolant was going through the radiator at the start, the fluid should still get very hot. I replaced the fluid with 50:50 mix with BMW fluids.

Any thoughts on this? I assume I will need to replace the thermostat housing.

Thanks!

 

According to --- https://www.perrin.com/blog/post/mini-r56-dtcs-list P2F07 is "P2F07 Thermostat Mech Error" Perrin is a long standing Mini guru, and has ready access to Mini-specific codes. Based on his translation and your symptoms, I'd replace your t'stat --- probably stuck open.

 

Thanks for your reply. Didn’t know about Perrin so that’s good to know for the future.

so if it’s stuck open, I guess there is no harm in driving it short term until the next housing comes in. But why doesn’t the engine get up to normal operating temps regardless it is stuck open?

Maybe the DME opens and closes the thermostat frequently to keep it within the desired temp range?

 

Yep mounds like a bad thermostat. Make sure you have the correct adapter also. For certain years and model you have an adapter as the updated the thermostats. 6/2010 to 3/2012 Base. What year and production is yours? Also we are always here for you if you have any questions.

https://www.northamericanmotoring.co...sing-help.html

 

Thanks the reply. I did but the adapter when I originally replaced the unit because I wasn’t quite sure if I needed it or not. I actually didn’t need it.

The main harness has one connector for the coolant temp and the other went to the opposite side. Probably some kind of feedback sensor from the thermostat or unless it’s electronically controlled. The housing was basically the same as the OEM so the connections where the same.

 

Ok, what year/production is your MINI? If you have a 6/2010 to 3/2012 you will need that adapter or you will get a code.

 

It’s 7/2010. But there is no logical place to connect that adapter to.

 

The thermostat is a non electronic device, it opens/closes based on temperature. Being in the stuck open position allows the coolant to always circulate through the radiator and cooling system.The only way you will get up to temp, would be to let it sit and run; if you are moving, the air flow going through your radiator will keep the temps down; if you are running on the Highway, you car would always run cool, which is not good for the engine. I would make sure you take care of it before the weather starts getting cooler. On the bright side, if your t-stat was stuck closed, you'd be overheating.

 

Ok, well they might have already changed out the thermostat before and then the adapter might already be there. This you can just swap in a new thermostat Got a picture?

 

Ok that’s what I originally thought about the thermostat. One of the connectors to it must be a position indicator. I read in another thread that it could be electronically controlled, that it was a heater. Apply 12V to it and it would act as a heaters. Didn’t make much sense to me why they would do that unless they were trying to optimize engine performance and keep it within a certain temp range by opening/closing it frequently.

 

No picture unfortunately, but the main harness essentially has the split connections to the coolant temp and thermostat position indicator.

i will take a snap shot when I change it out in a few days

 

Here are some picture. I changed out the thermostat with a REIN (same one that I took out). From the naked eye, I compared both thermostats position and both seemed to be in the same position. Upon further inspection, I noticed that the failure one was slight open (take a look at the picture). I used a light and shined through it. I replaced the thermostat tonight, and it's working properly. The fan did not kick on instantly when the engine was started from cold. I monitored the temp and it got much warmer. Took it out for a drive and got the temp up to 200-210F, which is in the ballpark range for normal operation.

Glad it got resolved. Hopefully this REIN will last much longer than 2 months….If not, I guess I'll have to get an genuine Mini housing.


Coolant temp connection

Thermostat position indicator connection

Slightly stuck open. I shined a light from the heater hose side, and you can see it wasn't shut all the way. This is from the lower radiator hose side.