[BMWfan73]

The last BMW I owned was back in 1992 - a 325i so I don't remember if it was like this then... but now that I'm getting my X3, I noticed that they have an oil temp gauge on the dash instead of water. Why is oil more important than water? Can anyone shed some light on this for me?

[S4NoMore]

Oil is a better indicator of engine temperature, i.e. warmup status. Water temperature increases pretty fast, and the only reason to have a gauge on it is to tell you that you are overheating. This can be done with a light or an alert message rather than a permanent gauge.

[BMWfan73]

Do you know the normal coolant operating range for the 35i? I have an Ultragauge device that plugs into the OBD2 port and I can set an alarm for things like coolant temp when it falls below or rises above a certain temp.

Originally Posted by S4NoMore

Oil is a better indicator of engine temperature, i.e. warmup status. Water temperature increases pretty fast, and the only reason to have a gauge on it is to tell you that you are overheating. This can be done with a light or an alert message rather than a permanent gauge.

[e30lover318i]

Unfortunately bmw has changed the way they do a lot of things do to the brainless car owners of the current generation. They removed the temp gauge because durning an overheating condition the vehicle is now smart enough to turn itself off. The 2010 e83 was the last x3 with a temp gauge unfortunately. Due to our analog generation being obsolete now “inserting the twilight zone episode for a better understanding” hahahah

[robbyd63]

Originally Posted by S4NoMore

Oil is a better indicator of engine temperature, i.e. warmup status. Water temperature increases pretty fast, and the only reason to have a gauge on it is to tell you that you are overheating. This can be done with a light or an alert message rather than a permanent gauge.

Still. I agree with OP, it's annoying that I'm always looking at oil temp now. In every other car I've owned it's always been water temp, and since that's what I'm used to I have no indication of what oil temp is bad vs good. Would have been helpful if BMW kept the blue and red sections on the gauge so I at least knew what to look out for. On hot days my X3 has seen the oil temp go right to the middle of that gauge and idles roughly when it does.

[Wgosma]

Originally Posted by BMWfan73

Do you know the normal coolant operating range for the 35i? I have an Ultragauge device that plugs into the OBD2 port and I can set an alarm for things like coolant temp when it falls below or rises above a certain temp.

Coolant should run in range of 100C ~ 110C or so. You can use the car's 'hidden menu' function on the OBC if you want to spot check coolant temp (and several other parameters, such as system voltage). Video here

There might be better video's on YouTube - when you enter the hidden menu you need to first 'unlock' it using a numeric entry, which is sum of the last 5 digits of your car's VIN number, before you can access it's menu- this function has been available on BMW's for a long time, you may have used it on your prior 3-Series car (?). Once in hidden menu mode the OBC readout will stay there until you either exit that mode or turn off the ignition.

[S4NoMore]

Originally Posted by robbyd63

Still. I agree with OP, it's annoying that I'm always looking at oil temp now. In every other car I've owned it's always been water temp, and since that's what I'm used to I have no indication of what oil temp is bad vs good. Would have been helpful if BMW kept the blue and red sections on the gauge so I at least knew what to look out for. On hot days my X3 has seen the oil temp go right to the middle of that gauge and idles roughly when it does.

Just look at it in the same manner that you looked at water temp. Take out the descriptor altogether - it's your engine temperature indicator. It just so happens that oil is the better indicator. Did you really use water temperature for anything other than interpreting if the engine is "cold" or "warm" or "overheating"? Blue and red sections were always the extremes, and as mentioned already these cars are so smart they will tell you on the HMIs if there's an issue, or shut down if it's bad enough.

In my F30 with N20, and now my E90 with N55, the oil temperature doesn't vary much. In the F30 I could see the changes in temp between "eco" and "sport" but it never went past 50% of the gauge sweep. In the E90 there's no engine mode variation, it always goes to about 2 hashes shy of 50% or 235F (if I recall correctly, with 250F being 50% of the gauge sweep).

At the most basic level, I believe the reason they did this is that on a cold morning your water temp might reach operating level but your oil temp is still quite low. So it's a simple matter of that little extra delay before you are driving as if you're fully warmed up.

My X3 has the diesel engine, which is not like N20 or N55 with mode-dependent temperature variability. It warms up to 50% of the gauge sweep every time. If you're running rough at that point, you have an issue - I'd be thinking plugs, coils, vacuum leaks, etc.

[najnad]

Originally Posted by robbyd63

Still. I agree with OP, it's annoying that I'm always looking at oil temp now. In every other car I've owned it's always been water temp, and since that's what I'm used to I have no indication of what oil temp is bad vs good. Would have been helpful if BMW kept the blue and red sections on the gauge so I at least knew what to look out for. On hot days my X3 has seen the oil temp go right to the middle of that gauge and idles roughly when it does.

Up to the middle of the gauge is fine, beyond that you need to do something to cool off...slow dow, turn on the heater full blast, etc.

[Wgosma]

Originally Posted by robbyd63

Would have been helpful if BMW kept the blue and red sections on the gauge so I at least knew what to look out for. On hot days my X3 has seen the oil temp go right to the middle of that gauge and idles roughly when it does.

Perhaps you can keep in mind that since the oil is what is lubricating the motor it's THE most critical fluid to (directly) monitor. These modern BMW's have sufficient brain power to alert us to the fact that the oil or water temp is 'out of line/approaching the danger zone' and also cause the car's motor to throttle back, etc. to protect the motor. This capability has not been in these (or other cars) for all that long a time, it's very useful protection to keep a driver from doing major damage to the engine.

If you think back for a moment to older cars, say 2000 or so model year and the operation of their coolant temperature gauges (on BMW's...and probably most other cars) those gauges were electronically 'dampened'....as we know the actual coolant temperature in a car's system continually fluctuates, sometimes up to +/- 15F degrees from 'nominal' as the engine load changes - the dampening of the gauge holds the needle more or less constant once nominal/normal operating temp. is achieved; hiding these temperature fluctuations from the driver is probably a smart design for most of the motoring public...if people saw their temp gauge swing up/down as they climbed then descended a hill or sat in commute traffic and watched the needle climb, many drivers would be thinking there is something wrong with the car's cooling system.

The coolant gauges in those older cars did give yellow, then red warnings as temps climbed to abnormal levels, but it was up to Mr Driver to heed that alarm and slow down or stop the car...I knew a few people who decided to drive that 3 or so more miles to their house after they saw the red gauge warning and voila, there goes the head gasket- inline 6 motors in particular with their relatively long heads simply don't tolerate overheat well at all. The newer cars will go into limp mode on over heat thus preventing the driver from toasting his motor.

[pungo]

My 2007 Z4 ///M coupe with S54 engine has oil temp, but no coolant temp like the x3. I can view the coolant temp on the nav display via my Intravee II interface, but that's another story.

Although I'd prefer to have both coolant and oil temp gauges, but if I had to choose just one, I'd go for the oil temp. On the track, at speed the oil temp will creep up after some time while the coolant temp doesn't move much higher due to the high speed air entering the radiator. The same can be said for Autobahn speeds or very high highway speeds. The oil is going to creep up, but the coolant doesn't because of the high speed air flow. A turbo will increase oil temps even more, though the coolant, not as much.

My 1990 Corrado has a factory supercharger and when getting into boost a lot, with higher RPMs, the digital oil temp shown in the instrument cluster will really creep up, letting me know to back off some to let it cool down

The Germans, with their high speed roadways, know how much oil temps increase at speed so provide the user with the ability to monitor those temps, even on my 30 year old VW.

[383vett]

Originally Posted by S4NoMore

Oil is a better indicator of engine temperature, i.e. warmup status. Water temperature increases pretty fast, and the only reason to have a gauge on it is to tell you that you are overheating. This can be done with a light or an alert message rather than a permanent gauge.

On the next model of the X3, the G01 starting in 2018, BMW back to water temperature on the X3. When the waterpump goes, there is no warning other than the engine shutting down and an overheating message. I certainly didn't get a warning light.

[Wgosma]

Originally Posted by 383vett

On the next model of the X3, the G01 starting in 2018, BMW back to water temperature on the X3. When the waterpump goes, there is no warning other than the engine shutting down and an overheating message. I certainly didn't get a warning light.

Perhaps the gauge change as the G01's have mechanical belt driven water pumps - no easy way to monitor it's condition and feed that info to the car's brain.