[Three_thirty_I]

As per the title, my E90 330i seems to be running colder than normal based on the temperatures that I am seeing on the hidden OBC menu (unlock 19 and 7).

Last night driving home with the outside temperature being around 14C the engine coolant temperature was between 77 and 82 degrees Celsius, and this has been the case for a while now and was pointed out initially as a possible thermostat problem, but then suspected as being faulty temperature sensors. I replaced both temp sensors since they are the cheaper initial items to replace, but no difference, so it can now only be the thermostat that's not closing and properly regulating the temperatures.

I gather that the correct operating temperature range is mid 90's to a little over 100 degrees Celsius, maybe even higher this and then in some cases a bit lower than 90 degrees.

So just want to clarify this and hear what it is supposed to be in reality.

[SDemetris]

I feel lime this is sort of a mystery for most people here because instead of a oil/coolant temp gage, we have the dumb mpg meter.. so i would like to know this as well

[Three_thirty_I]

Well, the hidden OBC menu shows the coolant temperature which is what I am looking at.

[Johnny D]

Normal operating temps are between 200 and 210. You'll have to convert to Celsius... I'm lazy.

[Three_thirty_I]

Originally Posted by Johnny D

Normal operating temps are between 200 and 210. You'll have to convert to Celsius... I'm lazy.

That's around 93 and 99 degrees Celsius, so makes sense from other threads that I have read so far...

[thecadman99]

Torque app shows mine anywhere from 90C to (highest I've seen yet) 103C slow pulling up a nature trail in Pigeon Forge.

Yours does seem a little "cool".

[GoRomeo]

I should read mine too. I have the Torque App. I once got a faulty thermostat code and I wonder if mine temp does not reach the normal temp.

[Three_thirty_I]

On another thread, this interesting reply! Check the spec PDF too on the linked thread!

Originally Posted by Volasko

A while back a member posted a link to a long detailed report about the N52 engine (http://www.e90post.com/forums/showthread.php?t=788821). There is lots of good info regarding our engines that I found interesting, particularly the design concept of the electric water pump (page 67). It describes that our water pumps move more or less coolant through our engines depending on the situations to maintain different engine temperature setpoints. During spirited driving the temperature of the coolant is kept lower to improve volumetric efficiency and thus more power. During eco mode it keeps it higher to thin out the oil to reduce parasitic losses (ie friction) on the engine to save fuel. Most importantly it shows the different coolant temperature set points and will answer your question quite nicely:

112 deg C ECO Mode
105 deg C Normal Mode
95 deg C Med output mode
80 deg C High output mode

I suggest taking a look yourself as it is described in better detail. Hell you can find out every damn detail about our engines in that report as its 75 pages!! Prepare to spend a few hours reading if you're super technical. Having a degree in mechanical engineering helped

[Eagle1oh7]

What is this hidden menu?? Is it in N51 powered 3ers?

[Three_thirty_I]

Originally Posted by Eagle1oh7

What is this hidden menu?? Is it in N51 powered 3ers?

It is. To access this press and hold the trip meter reset button and hold for 10 seconds, then the hidden main menu will appear where it normally shows the time and outside temperature etc. Then cycle to menu 19 by pressing the reset button until there. Now to unlock the hidden menus to access the temperature you need to input the sum of the numbers making up your car's VIN number. So for instance, if your VIN is AB12345, then you need to add these number up, so in the example it would be 15. Then once unlocked cycle to menu 7 and it will now show the coolant temperature.

For more information on the hidden menu and all of its functions, just do a google search - easy to find and lots of info!

[e90pilot]

Originally Posted by Three_thirty_I

On another thread, this interesting reply! Check the spec PDF too on the linked thread!

Great find! This is totally correct. The car will change it's temperature constantly. It's one of reasons that BMW decided to remove the temp gauge. It's really interesting how it all works. I looked at some live data from my car once. On the freeway the water pump is spinning at a low rpm and the t-stat is closed. Engine temp is around 112C. Adding a large amount of throttle will cause the pump rpm to increase and the t-stat to open. Downshifting a flooring the throttle actually causes the engine temp to reduce around 85C and the water pump to operate at max rpm.

As I got off the freeway and slowed down the temp decreased to 85C - 90C and is maintained there for city driving. Very interesting indeed.

[Eagle1oh7]

Originally Posted by Three_thirty_I

It is. To access this press and hold the trip meter reset button and hold for 10 seconds, then the hidden main menu will appear where it normally shows the time and outside temperature etc. Then cycle to menu 19 by pressing the reset button until there. Now to unlock the hidden menus to access the temperature you need to input the sum of the numbers making up your car's VIN number. So for instance, if your VIN is AB12345, then you need to add these number up, so in the example it would be 15. Then once unlocked cycle to menu 7 and it will now show the coolant temperature.

For more information on the hidden menu and all of its functions, just do a google search - easy to find and lots of info!

Sweet! Thanks for the info! I'm sure it'll come in handy!

[Three_thirty_I]

Originally Posted by e90pilot

Great find! This is totally correct. The car will change it's temperature constantly. It's one of reasons that BMW decided to remove the temp gauge. It's really interesting how it all works. I looked at some live data from my car once. On the freeway the water pump is spinning at a low rpm and the t-stat is closed. Engine temp is around 112C. Adding a large amount of throttle will cause the pump rpm to increase and the t-stat to open. Downshifting a flooring the throttle actually causes the engine temp to reduce around 85C and the water pump to operate at max rpm.

As I got off the freeway and slowed down the temp decreased to 85C - 90C and is maintained there for city driving. Very interesting indeed.

This is the crazy thing! The agents had the car for this after a specialist had picked up that the engine was constantly running cold, so they initially thought it was the thermostat and then changed their minds thinking that it could be the coolant temperature sensor. But the agents claimed they could not find anything wrong, translation, no codes came up. And they can't perform live tests anyway, at least so I was told. Now the thermostat is probably the problem, but it could even be something with the ECU since it is suppose to control what the thermostat is doing. All I can think is that the thermostat is stuck open...

[GoRomeo]

Originally Posted by Three_thirty_I

This is the crazy thing! The agents had the car for this after a specialist had picked up that the engine was constantly running cold, so they initially thought it was the thermostat and then changed their minds thinking that it could be the coolant temperature sensor. But the agents claimed they could not find anything wrong, translation, no codes came up. And they can't perform live tests anyway, at least so I was told. Now the thermostat is probably the problem, but it could even be something with the ECU since it is suppose to control what the thermostat is doing. All I can think is that the thermostat is stuck open...

I read here in the forum that if you can feel or press the top hose on the radiator when cold, if you can feel water circulating it means the thermostat is in fact stuck open but if you dont, then ur thermostat is not the problem.

Thermostat should always be closed when cold and open when hot.

[MrDummy]

Will doing this hidden menu trick effect warranty or will dealership know I messed with it?

[Three_thirty_I]

Originally Posted by MrDummy

Will doing this hidden menu trick effect warranty or will dealership know I messed with it?

Well, can't do any harm with it, so I can't see how this would be a problem, and can't think that it would be detected either. It's merely there to display information as far as I know, so can't do anything adverse to the car. At least this is what I remember reading when looking for information regarding the hidden OBC menu...

[MrDummy]

Also do u need to be park or any special instructions?

[MrDummy]

I can't get mine to work, I see code 19, type in my numbers added up from the full vin # and then it shows the 1_ part, then I go to 7_ and tried holding in button and tried doing nothing but it just keeps reverting back to time and clock?

[Three_thirty_I]

Can do this parked or even on the move (but not safe of course), and with the engine on or off as far as I know.

Originally Posted by MrDummy

I can't get mine to work, I see code 19, type in my numbers added up from the full vin # and then it shows the 1_ part, then I go to 7_ and tried holding in button and tried doing nothing but it just keeps reverting back to time and clock?

Did it show unlock after putting the combined VIN number in menu 19? It should then show the temperature in menu 7. I battled the first few times when I tried this and just ended up accidentally resetting my trip meter.

[MrDummy]

No it still shows locked even after I triple checked the math.

You don't add in the letters correct? Just the numbers in the full vin, right?

Thanks,
MrD

[e90pilot]

Originally Posted by MrDummy

No it still shows locked even after I triple checked the math.

You don't add in the letters correct? Just the numbers in the full vin, right?

Thanks,
MrD

No just the numbers after "KR"

[MrDummy]

Thanks will try in a few mins...