[moldcad]

After I set up both my Torque Pro and Dashcommand to check how fast the engine oil and water temps get into the "fully operational" value range, I'm actually somewhat worried with the coolant readings (the oil is OK). Namely, not only does the coolant temperature go up pretty quick (which is good), but it actually has the tendency to stay in a somewhat high territory...

I'm probably a little too obsessed with it (after having read the research thread on which cars do and which don't have the left-side aux radiator - mine is EU spec, so it doesn't have it) - but 115C during just cruising around in comfort mode seems a little high to me. How is yours?

[silverado]

Originally Posted by moldcad

After I set up both my Torque Pro and Dashcommand to check how fast the engine oil and water temps get into the "fully operational" value range, I'm actually somewhat worried with the coolant readings (the oil is OK). Namely, not only does the coolant temperature go up pretty quick (which is good), but it actually has the tendency to stay in a somewhat high territory...

I'm probably a little too obsessed with it (after having read the research thread on which cars do and which don't have the left-side aux radiator - mine is EU spec, so it doesn't have it) - but 115C during just cruising around in comfort mode seems a little high to me. How is yours?

I'm no expert but I think this may be getting into TMI (too much info) territory. The car has many safeguards against overheating and would certainly let you know if the coolant is too hot. I understand maybe wanting to do a lot of monitoring if you're pushing your car hard (repeated launch control, racing, etc.) but worrying about it while just driving down the road seems a bit much.

[Viffermike]

Originally Posted by silverado

I'm no expert but I think this may be getting into TMI (too much info) territory. The car has many safeguards against overheating and would certainly let you know if the coolant is too hot. I understand maybe wanting to do a lot of monitoring if you're pushing your car hard (repeated launch control, racing, etc.) but worrying about it while just driving down the road seems a bit much.

Not when U.S.-spec M235s get a second aux coolant radiator while Euro-spec M235s don't, as the OP alludes to ...

Personally, I don't think there's such a thing as TMI when it comes to monitoring operating temperatures on a performance car. At the very least, a coolant temp gauge (and digital speed indicator, natch) should be info display options along with fuel range, avg. speed, instant fuel consumption, etc.

[Supernaut]

Originally Posted by moldcad

After I set up both my Torque Pro and Dashcommand to check how fast the engine oil and water temps get into the "fully operational" value range, I'm actually somewhat worried with the coolant readings (the oil is OK). Namely, not only does the coolant temperature go up pretty quick (which is good), but it actually has the tendency to stay in a somewhat high territory...

I'm probably a little too obsessed with it (after having read the research thread on which cars do and which don't have the left-side aux radiator - mine is EU spec, so it doesn't have it) - but 115C during just cruising around in comfort mode seems a little high to me. How is yours?

I, too am running Torque and get 115C/240F routinely in cruise. As I posted in the Torque/OBD thread, I found an older guide for the N55B30 family that says the engine goes into a protective mode by reducing AC & engine output at coolant temps of 117C/246F which seems really close to the temps I get with casual driving in cool weather. True limp mode is higher at 125C/257F coolant temps. Oil temp cutoffs go much higher. I'm not sure if those numbers are different for the retuned M235 engine or if it truly skirts the protective parameters that closely.

[moldcad]

Thanks for confirmation, Supernaut - I only hope that at higher speeds, when the radiator does its job, the temperature will slightly drop and stabilize. I also don't think the high temperature at cruising is in any way related to the lack of the (second) aux radiator - if it was so badly needed at cruising speeds, tracking this car would simply be impossible!

[one1er]

Engines these days are programed to change temperature depending on driving conditions to either optimize performance or efficiency. Usually they'll run hotter when cruising and will drop a few degrees when under load, like closer to the mid 90's ºC

[Supernaut]

Originally Posted by one1er

Engines these days are programed to change temperature depending on driving conditions to either optimize performance or efficiency. Usually they'll run hotter when cruising and will drop a few degrees when under load, like closer to the mid 90's ºC

Indeed, the N55 guide shows target cylinder head temps for different driving modes:
108C/226F=Economy mode
104C/219F=Normal mode
95C/203F=High mode
90C/194F=High mode and control with characteristic map thermostat

I also didn't realize the coolant pump is electric and can shut off for warmup and keep running after the engine is shut down.

Here's the rationale for the higher temps with lighter loads:

[moldcad]

Thanks for that info; I didn't have an opportunity yet to drive spiritedly with my Torque installation on. Will try it and report my temperature readings here for reference.

PS Indeed - in my F10 (which probably had a very similar water pump management system), I usually saw 95C on the motorway; never paid attention to it when cruising though...

[moldcad]

Supernaut - your info is spot on! Yesterday I was on my way back home after a long (1,500 km) business trip, and - driving on a motorway when the clock went past the 2,000 km - I did the "what the heck" thing and floored the gas pedal

The speed of 250 km/h I kept for several seconds only (still too low a mileage), but - having my ODB2 transmitter in and DashCommand running - I saw 90 C of coolant temperature for the first time.

Just to remind those who didn't follow this thread: seemingly defying logic, the coolant temperature can go as high as 115 C when just cruising - but with more load (and admittedly also air action on the radiator), it goes down to some 95 C in normal highway driving. When going extreme (like I did for the first time with this car), the coolant temperature drops by another ca 5 C. So - all seems to be fine (even without the left-side additional radiator)

[Supernaut]

Originally Posted by moldcad

Supernaut - your info is spot on! Yesterday I was on my way back home after a long (1,500 km) business trip, and - driving on a motorway when the clock went past the 2,000 km - I did the "what the heck" thing and floored the gas pedal

The speed of 250 km/h I kept for several seconds only (still too low a mileage), but - having my ODB2 transmitter in and DashCommand running - I saw 90 C of coolant temperature for the first time.

Just to remind those who didn't follow this thread: seemingly defying logic, the coolant temperature can go as high as 115 C when just cruising - but with more load (and admittedly also air action on the radiator), it goes down to some 95 C in normal highway driving. When going extreme (like I did for the first time with this car), the coolant temperature drops by another ca 5 C. So - all seems to be fine (even without the left-side additional radiator)

It's good to know that info is accurate. I haven't had any opportunities to push the car hard even though it's broken in. I certainly don't have any opportunities to hit the rev limiter like that. Color me very, very envious.

[SwolePatrol]

Sorry to bring up an old thread. But my '15 M235i just showed up a CEL with the following codes U1408 and P0128. Car is running fine. I hooked up an OBDII reader, and it shows my coolant temp approx 220-228F while cursing in "comfort mode".

Is this normal? I looked at the temp guide, but not sure if that is reflecting coolant temp.

I cleared the faults as suggested, to see if it comes back. At that point I guess I'll work on checking the sensors. After I cleared the codes, U1408 remained as a permanent manufacture defined code while the P0128 has been removed.

Side note: is it normal to only have O2 sensor #2 show values and O2 sensor #1 not showing any?

[Maynard]

No such thing as TMI, but do yourself a favor and figure out what it is 'supposed to be' before you monitor it or get upset. I know I am constantly reminded of how different things are with these intelligent and overcompetent machines - i.e. for this, they have unused cooing ability that they can exploit as directed, rather than the old school sytems that were always just open or closed. And a rise in temp while going slower would be expected, even w/ the old school systems - at least now I don't have to keep the heater going full blast to try to keep it from overheating at a stoplight (that was the old version of the 'auxiliary radiator' c.1978).

[SwolePatrol]

I see what you are saying, but why would it throw a code if the temperatures are where they are supposed to be? It just doesn't make sense lol.

I'm hoping to attach screenshots of the codes when I get to the house, and hopefully this will help me get a clearer picture.

[allthatisntnow]

Ive got Euro spec cooling and on track the oil temp for me never exceeds 116c in ambient temps of 12-15c. The 8AT however does touch 100c (usually not much above 85c with spirited road driving) by the end of a 20-25 minute session. Which is more concerning for wear rates. I believe the transmission does have a heat exchanger with the engine coolant (which also helps tranny warm up) though which would explain the high temp ceiling. If i was going to get additional cooling it would be prioritised for the transmission more than the engine.