I had the Thermostat housing and water pump pipe changed at a shop on my 2009 Mini Cooper Hardtop. I hooked up an OBD2 scanner and watched the temperature.

The coolant temperature went from 160F to 180F to 200F to 210F. I pulled over and let the car cool down for a few minutes. I decided to drive back home (7 miles). I started it back up and it went up to 215F, so I opened the heater all the way open, since I thought it was overheating.

The intake temperature was 106F (as per my OBD2 scanner). The outside temperature was about 80 degrees.

Not sure what temperature the coolant is suppose to be at, but it just seemed like it was getting too high.

 

That sounds about right... 210F, 215F is normal operating temperature for an R56
I also live in an area where outside temperature is around 85F and intake temp is between 91F to 110F depending if you are in traffic or in a highway and with the oem intercooler, with an aftermarket intercooler it is a lot different.

 

That sounds great. I was worried that the engine was overheating. I didn't test drive it on the highway, just street driving.

I did notice the temperature drop to zero, and than back up to the normal reading range. A P0117 code showed up first. Than a few minutes later a P173B showed up. Not sure if there is an air bubble in the system that can cause that, or should I have the shop take a look at it.

 

Yeah you should go and have somebody to check that..
As for the temperature here is a tip, if you turn on the a/c fan on max the radiator fan will turn on until the temp goes to 188F and will stay there as long you have the fan on max speed.
What year and model of mini you have?

 

I have a 2009 Mini Cooper Hardtop.

Interesting tip about the temperature. Is this during idling? I would think the engine will go above 188F if I drive it since the operating temp is around 215F as you mentioned above. Unless the radiator fan is suppose to regulate the temperature to 188F at lower speeds.

 

Does not matter if it is in idle. It will stay on until temperature gets to 188F then after that the fan will slow down speed then after a while when it gets hot again let say 190F or maybe a little bit more the fan will accelerate the speed again until temp goes down to 188F again. Now all this happen only when the engine reaches the operating temp first. Meaning that in the morning when the engine is cold if you turn on the engine and also the a/c fan it will not happen until first the engine reach its operating temp.

 

If you have an older thermostat housing your water temperatures will run about 215. With the newer housings available now water temps will run about 225. BMW raised the water temp for increased fuel efficiency. Most S models will open the bypass and lower coolant temps to 185 when the AC is on MAX. Later models will do this when the sport button is pressed. Some JCW's like my 2012 however always ran at the regular temp. Didn't matter what setting the AC was at or if sport mode was selected.

Reason number 297 for a Stage 2 Manic tune. My operating temps are now 185 all the time.

 

I put a new thermostat in my '08 Justa a few months ago and the temp stays at 215° all the time unless I'm on a long uphill climb when it'll drop to the 180°s

 

A brand new thermostat was installed. So when it was going over 200F I was getting concerned. When it went over 210F I was a bit panicking. I am not sure when the overheat light goes on, but I didn't see it go on. I didn't want to wait until it came on since they sometimes come on too late.

I'll test drive it again and see if it stays below 220F.
Its good to know that is it normal to have such a high temp, given that the manufacturer is trying to increase the MPG. Didn't know about the bypass, or is that just the heater core.

Kind of counter-intuitive. Going up a hill should increase the temp of the engine since the load is higher. I guess the fan kicks in and helps cool off the engine.

 

Probably the case. Can't hear the fan over the revs.
"Kind of counter-intuitive. Going up a hill should increase the temp of the engine since the load is higher. I guess the fan kicks in and helps cool off the engine.

 

I can't comment on the Justa as I've never looked at the ECU code, but that is different behavior than I'm used to seeing on the S and JCW. The bypass is not in the heater core but is a function the thermostat itself. The ECU controls the opening of the thermostat. With the AC on max the ECU bypasses the normal control process and opens the thermostat. Turn off the AC and temps will climb back to 225.

 

I know my JCW sets at 215-219, the Cooper should run about the same, if not a a bit cooler being there is not hot turbo under heat soak , but the thermostat on the Cooper and Cooper S is shared its the ECU that sets the rate. Sounds about normal.

 

Er....part of the reason it's a pressurized cooling system is to allow the water/ATF mix to get over 212 without boiling. I have no idea what the problem would be with 210. The systems in these cars always let the coolant get hot before kicking the fans in to cool back down - it's constantly cycling through that process.

IMO it's all a false alarm.

 

So when the AC is on max, the thermo opens, and fluid goes through the engine to cool it off. At some point I would think the temp has to get over 200 unless the engine is designed to operate at a lower temp. So when the temp goes to 220 is that because the thermo hasn't opened?

I also noticed something else kind of weird. The radiator reservoir got really hot when my engine got to 220. Doesn't make sense.

 

FWIW, my 2009 Clubman S coolant usually runs about 221 degrees F under normal conditions as checked via ODB2 port.

The system is pressurized allowing for a higher boiling point.

 

Does the reservoir also get hot also? It is made of plastic. I thought the reservoir was only used when the coolant was low. So would stay cool even when the engine is at operating temperature.

 

Good question. My understanding is that there is some suctioning back and forth of coolant between the reservoir and the rest of the system as the system heat up and cools down, but there is not a constant flow through the reservoir, so the coolant in the reservoir should not be very hot, except for heat picked up from the engine compartment. I have heard of cracks developing on the bottom of the plastic reservoir.

 

The reservoir gets pretty hot. I wasn't sure if fluid passes through the reservoir when the engine is at full temp. The engine got up to 220. I turned the air on and it fluctuated between 180 and 220. At some point it went to zero and the engine light went on. I reset the engine light and the temp went back to the normal range. Not sure if there is air in the system. I bled the one screw on the thermostat several times on different days,

 

You can glean information from these tech articles, the cooling system section:

http://www.pelicanparts.com/techarti...r_R56_Tech.htm

I remember one of the articles discusses squeezing the radiator hose to pump/bleed air out of the system. Also pinching off one of the hoses while the engine is running you should feel pressure build up on one side indicating that your water pump is working (I think the plastic impeller inside the water pump can break which would mean no/little pressure). That was discussed in one of the articles also.

And there's the auxiliary water pump but that is electric so it would probably throw a code or check engine light. BTW there was a recall on the auxiliary water pump.

I don't understand what you meant by the coolant temperature going to zero. It also seems to me that once the coolant gets to 220 it should stay there and not go down to 180. But I am no expert.

You said you got a check engine light and cleared it? Do you have a way to read the codes? Anytime I see a check engine light I want to know what the code was before clearing it.

 

Here's a good post with a PDF file explaining how to properly bleed the cooling system. https://www.northamericanmotoring.co...ml#post3397203

 

The thermostat temperature went to zero because the sensor is having a problem. the code P173B popped up. I was thinking it is caused from an air bubble, or maybe the tech damaged the sensor when reinstalling. I initially thought the high temperature might have damaged it but 220 or even 230 seems normal.

I reset the code and will test drive it tomorrow. I am more worried about the bleed screw. I hope I did not strip it.

 

Sound like you need to be sure the system is bled properly first. If it is, sounds like a faulty thermostat which is located in the thermostat housing, or a faulty temperature sensor which is mounted to the engine separately.

I've also read of trouble with the connectors for either of those two items getting damaged and needing the connectors replaced (ECS Tuning sells them I think). I believe the two connectors look similar and share some parts.

On the Pelican Parts website I think I read, that there is an o-ring on the bleedscrew, so that makes it sound like it might be removable in case you want to inspect it and make sure it's not damaged. Be careful not to crossthread plastic. I think they also talk about how far to open the bleedscrew.

 

Greentrees, it sounds like you have a faulty temperature sensor or connector if you got a zero reading. Check that first then bleed the cooling system.

 

For an R56, is the temp sensor integrated into the thermostat housing? The thermostat and housing is new.

 

Originally R56 had the sensor in the therm housing but in 2011/12 there was an R56 thermostat 'fix' and many sensors were relocated within a new hose. There was a new wiring harness added, too.
Perhaps only these replacements are available now?
In the pic I think the new sensor's in the hose and the new cradle to connect the sensor is shown above it.
Hope this helps...