Hello All!

I own Mini Cooper S 2006 convertable, automatic. A few weeks ago I started to notice a weird problem: after stopping on a traffic light (idle at 800RPM) the engine temp goes to the red zone very quickly. I hear the fun going on. If I put the transmission on neutral and get RPMs to 3,000 (still waiting on the traffic light) then the temperature quickly goes back to normal. Also, it goes back to normal as soon as I start driving.

I've spoke to a couple mechanincs already but they didn't have any good ideas. I read on the forum that it can be related to termostat but I am not sure how it explains the fact that the temperature goes back to normal when I go to high RPMs.

Thank you in advance!

 

Did you mean: High coolant/water temperature?

Unless you have added a aftermarket gauge you do not have an oil temperature gauge.

 

Right, coolant/water temperature. Sorry, just a typo.

 

if the thermostat isn't opening all the way, then the low pump speed along with the partially closed t-stat can cause this. Also check that the cooling system is well bled, air in our cooling systems is a real pain.

Does your supercharger rattle?

Matt

 

Thanks! This is a good explanation about low pump speed + partially closed thermostat. Is there a way to determine if it is just a broken pump or broken t-stat?

Yes, the system is well bled, the first thing I did after noticing the problem.

It is hard to say about rattle. I think the sound didn't change.

 

the pumps are pretty solid. If it does start to go south, it will seep coolant and the level in the resevoir will start to drop. I haven't seen any impellors that have worn away. The pump drive on the back of the SC is known to go south, but if it's really shot, you get a lot of noise from the back of the supercharger, and you overheat at pretty much any rev...

Thermostats fail more often, and is a good place to start....

Matt

 

Thanks!

 

Would a low speed fan resistor failure cause this?

 

Well, I hear fun on low speed and then on high speed. And I don't think it explains the high-RPM "solution".

 

If the low speed fan wasn't working simply getting more water thru the radiator will lower temps as the radiator will bleed off some temp w/o moving.

 

Possible, will be checking all of that over weekend

 

I changed the thread title to reflect this.

 

Just to close the thread: it was t-stat. Replaced it on Sat and had extensively test-drived the car on Sun without any problems.


Thanks everyone!

 

Good it all worked out.

Thanks for letting us all know.

Matt

 

Did you flush and refill the system with the T stat replace ?

Did you test the thermostat on the stove or just assuming now that was it ?

Dont think this is case closed until you have tested the T-stat. Just flushing and refilling and re-bleeding the system may have indeed been the cure.

 

You need to go to better mechanics..... this is a simple thermostat problem, probably one of the simplest and most common cooling system problems.

Edit: I see the problem is fixed.