Hello all,

i own two 2009 mini coopers, one is a normal cooper and the other is a S. the cooper seems to have an issue with keeping the coolant temprature above 85 degrees celsius.

tools used during the test:
KIWI WiFi
REV2 PRO for iPhone

conditions during the test:
6% humidity
32 Deg C outside air temp

i performed the following test:

started the car and let it run until the temp got to 105 Deg
the fan kicked on after 105 Deg
the fan never turned off and the temp dropped to 85 Deg
turned on the A/C and the temp stayed at 85 Deg
turned off the A/C the fan kept running
turned off the car and the fan stopped
turned on the car and the fan did not come on until the temp reached 105 Deg agian.

in short, the fan stays on when you drive the car and will not turn off until you turn the car off.

i performed the same test with my S and had different results:
started the car and let it run until the temp got to 105 Deg
the car never got to 105 Deg
drove it and turned on the A/C then parked
turned off the car
turned on the car
the water temp was 106 and the fan turned on
reduced water temp to 90 and fan turned off

i am guessing that my S is running normal and my Cooper is having issues.

any ideas on what this could be?

Ross Kopp

 

Wait wait wait wait...... you are concerned that your car is cooling TOO MUCH rather than not enough?? I wouldn't say there is a problem at all. The S is a turbo version and the air inside a turbo runs more efficiently at higher temps. So I'm willing to bet the S from the factory runs hotter a tad. Cooler intake temps mean better gas mileage and performance in a non-boosted vehicle so there would be more benefit to lower running temps in the non-s than the S. The S has a tightrope to walk between hot air in the turbo for performance and cool air in the intake side for performance/economy.

In short, though I'm not a MINI expert, I am a life long car nut who knows the ins and outs of a motor, and I think both cars are running perfectly fine.

 

No, the car is not running perfectly fine. when you have a car that does not maintain the temperature of 100 to 105 C parts start to expand and contract.

all mini coopers run between these temps unless a different thermostat is fitted, for instance, track racers that run the Mini Challenge run a 85 Deg C thermostat keeping the engine cooler, but at a constant. my mini is not keeping a constant temp which is bad.

you are correct in stating intake temps when low, are good, but its not what im discussing. its water temps i am worried about.

 

The cooling fan is not on constantly at some special speed to keep a constant temp. Temps will always fluctuate when the car is running. The fan kicks on at a designated temp and it kicks off when it cools to a certain temperature. There is no constant temperature, and yes the numbers can have a slightly noticeable gap sometimes.

Moreover, sorry you got so defensive about my post, but I still don't see where there's a problem. If your fan relay was not kicking in, the car would over-heat because the fan wouldn't come on. I can't see an issue where the fan would stay on too long causing "over cooling". 85c is 185f. I don't see that being low at all..... looks 100% normal for a typical engine.

MORE YET. You're using a phone app with no actual physical hardware that connects to the car? That's what I'm reading, though I don't know about that particular app or product. I just couldn't let myself trust readings from a phone app to be 100% accurate.


In conclusion, the car cooling down to 185 sounds(though higher than most cars I've dealt with) like a normal car to me and the fan kicking in at 221(also sounds high to me compared to most), seems normal. I just don't see your concern. If the car runs and drives and cools fine, why are you concerned right now?

 

not offended, just my style of writing plus i have been in germany too long...

here is the issue. back in 2011, the car went into the shop because the water pump went out and it was replaced. i properly bled the system after finding out the BMW mechanics at the German dealership screwed it up.

the basic principals of a thermostat is to keep the engine at a constant. the variation in the system is the radiator and the fan cooling the radiator. the thermostat opens ever so slightly when the temp is over a certain threshold. once that threshold is met, then the water is changed out from the cooler water in the radiator. once the radiator inlet water get to a certain temp, then the sensor on top of the thermostat housing tells the computer that its time for the fan to cool the water in the radiator. once it reaches a cooler temperature, the sensor on the thermostat tells that the water is now cooler and eventually shuts down.

if the thermostat stays open, the water never gets below the threshold for the fan to kick off.

i measured the water temp with a laser thermometer in my MCS and the water was at around 70 Deg C after the fan shut off. this tells me that it met the lower threshold for shut off unlike what took place in my MC.

so here are my statics for the MC:
*water stays at a constant 85 degrees once the fan kicks on for the first time regardless if the A/C is on or not.
*the car needs to be shut off for the fan to turn off.
*the fan turns on for the first time at the recommended threshold for water temp 105 Deg C

my diagnosis is the thermostat housing needs to be replaced, but before i go and purchase the item, i want to see if someone else has had such a dealing with the cooling system.

 

my concern is that not only will the cooling fan prematurely go out, but the Peugeot motor is not known for operating in inconsistent temps. if the head gasket goes because of this, and i am afraid it will if i let it run like it is, then i will be up the river with no paddles and a waterfall just around the corner... if you know what i mean...

 

See, and again, I personally do not know the details of this engine in whole. I can only help based on my over all car knowledge, and to me these cars run hotter than most, and a fluctuation like that is not news to me lol. If there is more technology in these cars to keep temps more consistent, I was not aware of it yet.

Hopefully you can get a fellow MC owner who might be up and up on the technical aspects of things to give you the exact info you're looking for. If the cooling fan flat out never shuts off once it has kicked on, until the car turns off, even when running down the highway with the ac off, clearly there may be an electrical issue.

 

All,

attached are two charts showing the cooling of the system. if you look on the MC, the fan kicks on right before the temp starts to fall.

the MCS shows no sign of falling like the MC does but instead maintains the temp.

 

The quoted hasn't been my experience at all. I've been monitoring engine temps on my R56S for several months. Once it warms up, it's always within 5+/- of 223 (F), whether I'm driving in town, on the highway, quickly, or relaxed. Of course that's on an app. But I do trust it, since it's just reading the obdII data.

Unfortunately, I don't know about the Justas, so I cant help with the original question.

 

My '12 Justa is similar--it runs right around 220F once it has warmed up, and the temperature doesn't fluctuate much that I have noticed.

I'm also using the OBD2 port, reading the coolant temp on my ScanGauge.

 

On 4th Feb 2013 robbo mcs wrote an excellent post on this forum explaining the symptoms of thermostat/temp sensor mismatch.

It certainly explained my fan-running problems and I think it's probably the best-explained and most-relevant post, IMO, on NAM; certainly for me...

Do a search and see if it is helpful in your case, too.

(It was called 'Does your JCW's engine fan run after turning off the car?')