I recently got an OBDII dongle and have been monitoring my coolant temp, voltage, ect. I've noticed that my coolant temp is normally between 200 and 208 but usually between 203-205. This seems a little warm to me, does anybody know what temp it should be? The car runs just fine, and I am in Texas at the moment, with a forecasted high of 104 today.

I just flushed and replaced my coolant a month ago, I went with an 80:20 mix of distilled water and coolant with a bottle of redline water wetter in there too. I wasn't having any cooling problems, but I figured it might cool better with the mostly water mix (I'll make sure to switch back to 50:50 before winter). The car has 82,000 miles, and as far as I know the original thermostat. The radiator looks OEM, though I am running a 17% pulley on the super charger (not sure if that affects cooling since it drives the water pump) and I have an aluminum coolant tank since the plastic one split at the seam, but other than that, I'm pretty sure the coolant system is stock.

The car runs fine, seems to cool fine, and isn't even running the fan after I stop and turn it off, but I'm just not sure if there's anything I need to do to make it cool better, or if it's fine the way it is.

 

 

My steady state is 193 per ScanGaugeII, but I live in a cool climate on the coast.

 

My R53 is happiest around 88*F through the OBC in the speedo. That being said, here in hot AZ, it's not uncommon to see numbers in the 88-100*C range (190-212*F).

I believe low speed fan kicks on at 212F, and high speed kicks on in the mid-220's.

 

I wrote this up a while back:

OK, the Mini Cooper Coolant systems functions as follows; low speed fan switches on at 221 and the high speed switches on at 234. When the AC is on, the low speed switches on when the system pressure is at 116 PSI with the high speed switching on when the system pressure reaches 261 PSI. The high speed fan will run without the AC being on if the set point of 234 is reached. On the Gen1 car, you can bring up the coolant temperature inside the car (will read in Centigrade) with the set points being 105 and 112. The cut off is 7 F below the cut in.

 

Racing guy -

WHY...the Water Wetter ?
That's mostly to be used on the track in place of coolant (which is an incorrect term) so you don't slime up the track surface (make it slippery) if you have a coolant system problem. Your 80/20 mix is a very good choice though.
"Coolant" does NOT transfer heat very well, plain ol water (or distilled) is the best at that task. The Antifreeze is good at holding corrosion at bey and is good for lubricating the water pump. And also for those folks in colder climates to keep the "freezing" problem down when the ambient temperature goes below zero.

Mike

 

Hadn't heard this before. Can't find it with search - any hints where I could find how?

 

Check out Item # 17 of the below thread. Lots of good stuff in the FAQ section,

https://www.northamericanmotoring.co...questions.html

 

Sounds like a sticky thermostat. It should open up around 195F. My new car reads right around 195F from the obdii.

 

ECU goes into closed loop at 185 F. and "Normal running temp" according to Mini is 200-215 F. If you're running an average below 185 F. you're losing power and mpg.

Coolant does not lubricate water pumps (Common Myth). There is a seal between the bearing and the coolant to prevent it front contaminating the bearing. When a water pump starts "weeping" out the hole on the bearing chamber to show the inner seal failure.

Straight distilled water is the best for heat transfer in a cooling system.

Antifreeze (coolant) - is just what the name implies, it keeps water from freezing and most have a corrosion inhibitor in them.

Water Wetter and pretty much most of your "Performance Cooling system additives" - pretty much just glorified soap. (Don't believe me? Do some research) These can leave a coating between the metal of the block and the water actually slowing down heat transfer from the engine to the water (the reason they show lower temps in the advertising). If you run a cylinder head temp gauge you would actually see the metal temp increase compared to straight water. Some of these do have a corrosion inhibitor in them.

That being said, you do need some type of corrosion inhibitor for obvious reasons and if you live in a place that gets cold you need antifreeze to keep the system from freezing.

I run a 95/5 mix of Water / Coolant in my system and have no issues even in the hot desert running hard.

 

Mike, mostly for the corrosion protection and a little in hopes that it might decrease coolant temps. I was a little nervous about putting mostly distilled water into a cast iron block even for just a few months. So I probably put more antifreeze/coolant in than it needed, but I didn't want to regret not putting enough in down the line.

 

I did a fair amount of reading on water wetter, though I haven't done any research of my own (though this experiment is the beginning of my own research; I'm monitoring the coolant temps, and plan to switch back to 50:50 in a month or 2 and see if there's a difference) But what I read was that by functioning as a surfactant, it decreases cylinder head temps and hot spots. Though I don't have a head temp gauge. I have't heard about it leaving a film/residue in the cooling system though, that's interesting.

 

Yeah we went through it and a few others in testing and found just straight water with a higher pressure cap was the best for a full race vehicle.

You definitely need a corrosion inhibitor for a street car

 

Thanks!

 

g to Mini is 200-215 F. If you're running an average below 185 F. you're losing power and mpg.
I replaced my car thermostat to open at 185F and my car temperature run below 185F i dont feel my car loosing power at all.. Im willing to sacrifice a little lower gmp than overheating....

 

If you have to run that low of temp thermostat to prevent overheating then you are just masking a problem somewhere in your cooling system.

You may not "feel" any power loss but you are not making all the power you can because in open loop at that temp you do not see an optimum fuel mixture or as an aggressive ignition advance.

 

Some folks thinks that running a cooler temperature is better. No, not unless you are racing, tracking, or autoXing your Mini in hotter parts of the country. There is thermal efficiency to consider. Cooler is usually not better. The coolant system is pressurized for this very reason. The temperatures at different parts of the motor were designed by engineers and technologists. Coolant system is designed to reach higher temperature than pure water at boiling point at sea level. What govern the engine temperature primarily is the thermostat. The coolant sensor for the ECU plays the secondary but also a critical role in switching on the radiator cooling fan. But if you are driving flat out on a track, the chances are the thermostat is doing all the work regulating the motor temperature while the DME's fan control never do anything until you come into the pit.

 

I had this set up for 10 years 02MCS and so far not an issue, i live where normal daily is around 84-90F. I am aware of the loss fuel economy but im willing to sacrifice... I am not worried about the gas prices....

 

You're missing probably around 5-10hp also.

 

My car has a new thermostat and it runs right about 180 degrees and in closed loop. I monitor it via a scanguage. When I decelerate it goes to open loop but back to closed when I accelerate.

 

How do you know it's in closed or open loop? I just replaced my thermostat yesterday and it's running noticeably cooler, 180-196 degrees F. It's also 33 degrees and raining outside...

 

 

is there published literature on the cooling system and the set points? I’d love to read it and understand more since i always fear over heating

 

If MINI/BMW offer a "factory" service manual for the car this can contain very interesting info about the engine/car. I have had these for other cars -- the set for my Porsche Boxster weighed in at 64lbs and cost $350 discounted down from $3000!.

Prior to getting the manuals I used an OBD2 code reader/data viewer to view coolant temperature in real time -- the dash temp gauge is just an animated idiot light -- and observed the fans switching on at 212F and switching off at 205F or switching to high at 216F.

For my JCW I have not bothered to use my OBD2 tool to observe coolant temperature in real time. I have data logged the engine though and have observed the coolant temperature runs a bit hot in the range of roughly 220F to 230F with 226F being the "average". This is believe it or not not really alarming to me. A hot engine has less internal friction due to "cold" oil -- remember in the case of my JCW and 0w-20 oil the "20" is the oil's viscosity index at 212F which I consider the oil's working temperature -- and the oil is hot and this keeps the water boiled out of the oil and the oil is better for it.

The most common logs are for my work commute and this consists of an approx. 30 mile commute mostly at freeway speeds. The coolant temperature is pretty darn steady. By contrast my Hellcat coolant temperature runs around a high of up to 217F (I think the fans come on at 217F) to just under 190F under the same conditions as my MINI.