I've only had my 05 MCS for about 3 months. It has just under 29K miles. I guess I haven't had it long enough to really pay attention to what the temp gauge is reading. Anyway my hubby was driving it the other day and noticed it was about at the 3/4 mark. We checked the coolant and cleaned the air filter.

Now I'm noticing it's running consistenly at just past the half-way mark --and it could swear that it normally runs below the half-way mark (but like I said...I haven't had it that long so I could be "flashing back" to my other vehicles ). What is the norm?

And then this AM I noticed that when I started it up it was at the very highest point for about a mile...then slowley started to go down to the just above half-way mark. Is this normal?

I have an appt to take it to the dealer (2 mos left on warranty ) in about a week. Also have the SES light on occasion and the scan is saying it's one of the 02 sensors.

 

Sounds like you need a new thermostat.

 

Don't coolant leaks usually coincide with the thermostate issue? I have yet to see any leakage.

It sucks that this happened so quickly after buying the MCS, but on the flip side, I'm so glad both of these issues (o2 sensor) did happen now just short of the warranty expiring in a couple months

 

Coolant leaks dont have to coincide with a bad thermostat as the T-stat is an internal component. That said, I would ignore the temp gauge all together, it stays in the same spot all the way from 180 degrees to 220. If you want to see if the temp is all right get somebody to hook up either a ScanGauge II or a LapLogger to your car and read its actual temp from the OBDII port. It makes no sense for the gauge to be at the very top before you even start a drive, the car hasnt even warmed up yet. I assume it was at the very start start of the drive, right when you turned it on, right? If that is the case then you may be in the need of a new coolant temp sensor not a t-stat.

 

Thanks for the info - very helpful . Yeah the temp guage starts out at the very highest as soon as we start -- definitely not normal.

 

Either a bad coolant temp sender or a bad gauge then. At the risk of narrowing to much, a bad coolant temp sensor causing it to jump like that would probably trip a CEL, so you may be looking at a gauge cluster problem $$$. Speculating though.

 

Good thing we are still under warranty -- 2 mos. left and counting!

 

It seems like it's the thermostat causing the problems. I had the thermostat go bad and it wasn't pretty.

 

I had the same problem but when I checked to see the coolant was low. I've read different threads on using wet wetter and so far it's really working well. I probably don't have a thermostat problem, I'm just faced with 115+ degree weather in AZ.

 

You think there is any danger in driving it until it's fixed? Coolant is staying steady. Temp gauge is doing the same thing every day now...starting at highest point then going to just over half-way mark and staying there.

I can't get it in to the dealer until next Monday and it's our daily driver.

 

So my mini has been at the dealer since yesterday. Also had the bad 02 sensor replaced and some service done. As of yesterday evening, they were still scratching their heads re: the gauge. Said they cannot duplicate, nor find anything wrong.

I did learn while I was dropping it off that the coolant tank and thermostate had already been replaced on warranty for first owner. I had them keep it overnight so they can start it up cold and see that the gauge immediately goes to hot...then scrolls down to over halfway mark within just a couple minutes. To me it seems a no brainer if they can't find anything else wrong...it's the gauge, but waiting for them to come to that conclusion
...

 

I'm not a mechanic by any means and can only tell you from my personnal past experiences. With that said, if the dealer can't mimic the problem then it seems like it's a hardware error. I would say that if they changed out the coolant and thermostat (good thing it was under warranty) then maybe your faced with another defective thermostat and it does it every now and then.


Maybe get another look under the hood from a different respectable mechanic...... HMMMM! Sorry I can't be of more help anyone else?

 

For blonds, the temp gauge pegs hot with fresh start of the engine.... then it goes down.

For redheads, it pegs overheating with steam coming out of the hood.

For black haired folks like me, it's cool as a cucumber.

 

LOL I did think to make sure we weren't reading it backwards

Anyway they were very nice and kept it an extra day but couldn't duplicate. Was OK cuz I had a nice brand spankin new Bimmer to drive in the meantime (not a fun as the Mini though).

So it's not doing it now. It figures . However, although I specifically told the service writer not to let them do it, they reflashed my software . So now I have to take it to the local Dinan dealer on Monday to get my Stage 4 software put back in. Will take this opportunity to have the 2nd opinion. But I'm wondering, since they did the reflash when they installed the new 02 sensor, if this did something to "fix" the gauge issue.

On the bright side...we've had an opportunity to observe that the Dinan software (along with the other Dinan mods) really does make a difference in responsiveness off the line and power .