[rickinaz]

Really hot today, but my engine is running cool. After 20 minutes on the highway.

[FC4]

Now turn the AC off and watch your oil temp gauge climb.

[carzaddict]

WOW...my gauge never reaches that high. it always hovers around the 190-200 mark.

[FC4]

Originally Posted by carzaddict

WOW...my gauge never reaches that high. it always hovers around the 190-200 mark.

Different engine. These N55s run obnoxiously hot...standard operating oil temp is 240-250. Seems quite ridiculous to me. In contrast, my GTR with more than double the power is consistently in the mid-170s. I have to wind out several gears to get it north of 190.

[chiefneil]

Originally Posted by FC4

Different engine. These N55s run obnoxiously hot...standard operating oil temp is 240-250. Seems quite ridiculous to me. In contrast, my GTR with more than double the power is consistently in the mid-170s. I have to wind out several gears to get it north of 190.

The pic is showing roughly 205F. That seems perfectly normal to me and not obnoxiously hot at all. Over 250 is where I'd start to get concerned.

My 335i is always at the exact same temp shown in the pic. I thought it's be a bit warmer given today's heat (I'm in Phoenix too), but oil temp was the same today as on an 80F day.

170F actually sounds a bit low to me.... your thermostat probably isn't even open at that temp.

[Mik3ymomo]

Ran the car all day flat out against E92 M3's, C7 Corvettes, Boss 302 Mustangs etc road racing and the car never went over 240-245F.
A/C was off the whole time. Ambient temps were mid 80's.
Was doing 20min sessions, 6 sessions total. On Lightning@ NJMP
Brakes are squeaking though
Giving chase by -mik3ymomo-
NewJersey Motorsport's Park by -mik3ymomo-
BMW 435xi Msport by -mik3ymomo-

[DJ Rocc]

Originally Posted by Mik3ymomo

Ran the car all day flat out against E92 M3's, C7 Corvettes, Boss 302 Mustangs etc road racing and the car never went over 240-245F.
A/C was off the whole time. Ambient temps were mid 80's.
Was doing 20min sessions, 6 sessions total. On Lightning@ NJMP
Brakes are squeaking though
Giving chase by -mik3ymomo-
NewJersey Motorsport's Park by -mik3ymomo-
BMW 435xi Msport by -mik3ymomo-

Nice 435! What color are those grille slats?

I love this photo, hope my GC looks just as good from that angle! Same wheels too.

[Mik3ymomo]

Originally Posted by DJ Rocc

Nice 435! What color are those grille slats?

I love this photo, hope my GC looks just as good from that angle! Same wheels too.

Stock

[DJ Rocc]

Originally Posted by Mik3ymomo

Stock

Looks great! But some reason in the photo they don't look black?

[S4NoMore]

The operating temperature is controlled by the thermostat, which as we know controls flow via the electric water pump instead of a conventional plunger-type thermal switch. The set temperature changes based on driving mode - sport mode is lowest, normal is hotter, Eco pro is hottest. I don't recall exactly but I think it's something like 180-225-245 degrees F. Cooler is nominally better for performance, hotter reduces friction for efficiency. I've posted on this before, search to find the technical manual to learn more about it, interesting stuff.

[Mik3ymomo]

Car was driven in Sport + during every session

[ryanSTL]

I just randomly checked on my 435GC that I drove home for only about a 20 min ride. The hood and engine compartment are way more hot/warm than I'm used to. I got home 40 mins ago. guess it's been awhile since I've had a turbo car....

[ft1330]

I always hear not to push the car until it gets to 250... Go figure.

[JJS]

You can start to flex the engine's muscle once the oil gauge comes off its rest stop.

[Blubaron79]

250 is a normal operating temp. The car is designed to run that hot.

[chiefneil]

I got curious so I had a look at the N55 engine description from BMW. Here's what the manual says:

The engine control unit regulates the following temperature ranges:
• 108°C/226°F = Economy mode
• 104°C/219°F = Normal mode
• 95°C/203°F = High mode
• 90°C/194°F = High mode and control with characteristic map thermostat

The engine management sets a higher temperature (108°C) when, based on vehicle
operation, the engine control unit detects ”Economy” mode. The engine is operated with
relatively low fuel requirements in this temperature range. The internal engine friction is
reduced at higher temperatures. The increase in temperature therefore results in low fuel
consumption in the low load range. The driver wishes to utilize the optimum power developed
by the engine in “High and control with characteristic map thermostat” mode. For
this purpose, the temperature in the cylinder head is reduced to 90°C. This temperature
reduction promotes improved volumetric efficiency, thus resulting in an increased engine
torque. Adapted to the relevant driving situation, the engine control unit can now regulate
a defined operating range. In this way it is possible to influence the fuel consumption and
power output through the cooling system.

System Protection
If the coolant or the engine oil overheat during operation, certain vehicle functions are
influenced to the effect that more energy is available to the engine cooling system.
These measures are divided over two operating modes:
• Component protection
- Coolant temperature between 117°C/242°F and 124°C/255°F
- Engine oil temperature between 150°C/300°F and 157°C/314°F
- Result: The output of the air conditioning system
(up to 100%) and of the engine is reduced
• Emergency
- Coolant temperature between 125°C/257°F and 129°C/264°F
- Engine oil temperature between 158°C/316°F and 163°C/325°F
- Result: The power output of the engine is reduced
(up to 90%)

[KGB_123_99]

Maybe slightly off topic, but is there any reason to monitor the coolant temperature as long as oil temperature is available? I assume that if the cooling system failed the oil temperature would rise north of 250F. Is this correct?

[n55x3]

Excellent post chief!!

Definitely ties in with my real world experience. On my MSport RWD 335i, when I am out playing on the back roads really pushing it in sport or sport+ the car actually runs cooler than on my normal commute in comfort mode.

[Ali Shiralian]

Originally Posted by n55x3

Excellent post chief!!

Definitely ties in with my real world experience. On my MSport RWD 335i, when I am out playing on the back roads really pushing it in sport or sport+ the car actually runs cooler than on my normal commute in comfort mode.

Because when your driving fast, there is more airflow through the intercooler, hence it keeps it at a cooler temperature

[justinnum1]

my car is always 240-250. and it warms up quicker with city driving.

[Blubaron79]

Who really runs their car in Econ Pro anyway..?

[Skywalker27617]

I have never seen 23 MPG on my 435i.