[Wgosma]

Aha, I see it now-thanks!

[capocuoco]

Update- I finally replaced the sensor today. (It's the one that highlandpete has a picture of 2 posts prior to this.) Unfortunately, it didn't seem to solve the problem. I went for a 15-20 minute ride to "warm" the car up, traveling city speeds (up to about 40 mph). The gauge never budged. I did the "secret menu" testing again. Oil temp was 150F (65C) Coolant temp- Negative 198F again (-128C), the same as last time. I'm assuming that it's the thermostat stuck open. I'll have to read up about replacing the thermostat possibly or I might have to finally go to local mechanic. I'll have to look it up, but I think I read on another forum that BMW replaced their thermostat out of warranty for free because of known problems with it. (I can't remember, but I thought that person said that BMW extended warranty on thermostat to 10 years/??? miles. I'll look this up and report back.) Does anyone know about this thermostat extended warranty? Obviously, my car is a '12, so it's well out of standard warranty.

[Wgosma]

Ugh...motor is running too cold- maybe you can get the free thermostat install; think stat install not real fun, good luck!

[zeikei]

There has to be something else going on as well, the temp reading should be correct no matter how cold your engine is running. Before start it should be same as ambient temp and rise from there. I think your reading indicates some kind of electrical issue.

[supermarket]

The water cannot possibly be -128℃, no matter what the thermostat’s doing. Stuck open, stuck closed, doesn’t matter. This is a false indication. It’s not just implausible, it’s absolutely impossible.

You’ve got some electrical troubleshooting in your future, and if you’re not equipped to handle that, you’d be smart to bring in a mechanic now. The coolant temperature sensor was a good first step, but if that didn’t fix it, a new thermostat would just be throwing parts and money at the problem with slim chances of success.

[F30ed]

Fully agree with the last post. -128C is absurd number.

What I would do to detect the faulty part:
- buy all temp sensors that might be coolant related. All at once.
- disconnect each (not removing) and plug in new. Check the reading - it must at ambient temperature. If not - proceed to the next.
- Once faulty part found, replace and return the rest back for refund.

[capocuoco]

Yeah, I'm just going to make an appointment. I probably should have done that in the first place, but I tried to DIY the problem. I agree that it's most likely electrical because of the coolant reading of -128C which wasn't right from the start, but I thought that replacing that sensor might help. Maybe a wire from the sensor is bad? I've wasted a lot of time with this, but I always try to learn for the next time.

My car is up for inspection/emissions at the end of February anyway, so I might just get that out of the way too. Thanks for all the advice & tips everyone. I'm sure I'll be asking more questions, as I work on my car in the future.

[Wgosma]

Originally Posted by supermarket

The water cannot possibly be -128℃, no matter what the thermostat's doing. Stuck open, stuck closed, doesn't matter. This is a false indication. It's not just implausible, it's absolutely impossible.

You've got some electrical troubleshooting in your future, and if you're not equipped to handle that, you'd be smart to bring in a mechanic now. The coolant temperature sensor was a good first step, but if that didn't fix it, a new thermostat would just be throwing parts and money at the problem with slim chances of success.

Yes. OP had codes read at auto parts store but maybe the code is a generic one(?)..perhaps a fault code scan that will pull BMW specific codes is needed here?

[supermarket]

Originally Posted by capocuoco

Yeah, I'm just going to make an appointment. I probably should have done that in the first place, but I tried to DIY the problem. I agree that it's most likely electrical because of the coolant reading of -128C which wasn't right from the start, but I thought that replacing that sensor might help. Maybe a wire from the sensor is bad? I've wasted a lot of time with this, but I always try to learn for the next time.

If it's not the sensor, I suspect a wiring problem for sure.

[supermarket]

Originally Posted by Wgosma

Yes. OP had codes read at auto parts store but maybe the code is a generic one(?)..perhaps a fault code scan that will pull BMW specific codes is needed here?

That's not going to tell you anything different. There's a code indicating that the water temperature is too low, along with a water temperature reading that's impossibly low and probably the minimum possible value the car would read. The temperature reading is what caused the code. That's all you'll find, now you've got to troubleshoot the temperature reading.

[capocuoco]

Update: Switched shops and taking my car in for inspection & look into my temp gauge issue at the end of the month.
Meanwhile, I've been driving my car and everything has been fine. I've been checking my oil temp often with "secret" menu to stay informed.
I was driving out to my uncle's house yesterday and while sitting at a red light, I glanced at the gauges and surprise(??!!), the damn temp gauge was working. Pulled into a gas station, shut the car off and went into "secret" menu to read the temps. Oil temp reading was the same as dash reading and worked the rest of the day while driving.
Could a wire not read for that long (a month+)? Or was it loose and is temporarily working? Either way, it's going into shop soon to get fixed.

[Wgosma]

Interesting, you have a self-healing car! Keep us posted on new developments-
Bill

[Billfitz]

You'd have to be on Mars for the coolant to be at -198.

[capocuoco]

Originally Posted by Billfitz

You'd have to be on Mars for the coolant to be at -198.

I forgot to mention the coolant temp in the secret menu was back to a normal range too, it wasn't reading that crazy -198 temperature. So it's probably more than just the oil temp gauge wire/harness/assembly too. We'll see, but the gauge has been working the past few days. It seems like some exciting electrical problems in my future.

[330iZSP]

Did you happen to figure out what your issue was? I purchased a 13' 335i msport a few months ago and I'm having similar issues. My car takes forever to get to temp. I have already replaced the water pump, thermostat and temp sensor but still have the same issue. I did notice this weekend that my car would warm up fine without climate control on and stay at temp. Once I turned on climate control (heat or AC) my temps would drop and not hold constant. I've searched around on this issue tirelessly and cant seem to find a thread that has found the answer. I'm monitoring my temps with TorquePro not just the cluster. Any help would be appreciated a ton!

[dc_f30]

Also am having the same issue with my 2013 335i MSport. I noticed yesterday coming off the highway that my oil temp gauge hadn’t moved. I’d say as recently as last week it was working. “Secret” menu temp shows similar to OP’s numbers, -198 C water, 80 C oil. Will be checking fuses, connections today, but any thoughts/updates on those who’ve might have solved this would be great.

UPDATE 4/15: Apparently I also have the self-repairing model. After a weekend of checking but not changing anything, took it to work this morning and the oil temp gauge was working again. Can't say I did anything other than try and clean a few of the connections. I think the culprit is a failing thermostat. I've read other threads that talk about similar symptoms (mainly incorrect temps) by a failing thermostat. It has been added to the BMW 10-year/100,000-mile warranty list, SIB 11 10 15 or SIB 01 01 16. Will probably look to see if I can get this taken care of at a dealership sooner than later.

And just to elaborate on a details of the issue. Car seemed lumpy, under powered when it was occurring. The radiator fan was also going at a high speed, although didn't check the heater because it's already summer here. Odd note, it did show a correct reading a few times when in neutral, but then when I shifted into gear it would drop the temp to negative numbers above.

[Bryancar]

Originally Posted by dc_f30

Also am having the same issue with my 2013 335i MSport. I noticed yesterday coming off the highway that my oil temp gauge hadn’t moved. I’d say as recently as last week it was working. “Secret” menu temp shows similar to OP’s numbers, -198 C water, 80 C oil. Will be checking fuses, connections today, but any thoughts/updates on those who’ve might have solved this would be great.

UPDATE 4/15: Apparently I also have the self-repairing model. After a weekend of checking but not changing anything, took it to work this morning and the oil temp gauge was working again. Can't say I did anything other than try and clean a few of the connections. I think the culprit is a failing thermostat. I've read other threads that talk about similar symptoms (mainly incorrect temps) by a failing thermostat. It has been added to the BMW 10-year/100,000-mile warranty list, SIB 11 10 15 or SIB 01 01 16. Will probably look to see if I can get this taken care of at a dealership sooner than later.

And just to elaborate on a details of the issue. Car seemed lumpy, under powered when it was occurring. The radiator fan was also going at a high speed, although didn't check the heater because it's already summer here. Odd note, it did show a correct reading a few times when in neutral, but then when I shifted into gear it would drop the temp to negative numbers above.

any updates bro? im also having the same issue

[TheFalc]

I have this same issue. Oil temp not reading on gauge, hidden menu reading low oil temp and negative coolant, fan running excessively fast. Also, experienced the "It works suddenly" phenomenon.

One thing I want to note, is that monitoring via MHD, everything is normal (oil and coolant temp). It's not really running low, but for some reason, the way it's being calculated as seen in the hidden menu is borked, and very well could be throwing codes that aren't exactly correct. Sensors must be working if ODB readings are correct, ya?

I've found, that it may be the connector/wiring to the map thermostat. It's usually when I'm screwing around with those wires, that things tend to "work suddenly". Anyhow, I have it at a local indy shop and will follow up with their diagnosis afterward. Hopefully I can help resolve any outstanding questions on this thread.

[Gr-Racing]

any update on this having the same problem.
gauge works went it wants 2, car feels under power and fan are running on super high when gauge is not reading

[sbbii]

I also was wondering if anyone else has any updates? 2011 X3 3.5i MSport. Changed the water pump and thermostat about 6 months ago. As best as I can recall the gauge used to sit about mid-way during normal driving.

It's at the local BMW shop right now for something else and they checked it out and are saying "no problem found" which is encouraging in one sense, not so much in the other - lol! The self healing sounds nice, but with my luck the first indication I'd have of an overheating problem would be after significant engine damage had occurred :-(

[garanadhav]

Originally Posted by capocuoco

I have a '12 335i Sportline 6MT. I was driving home from out of town and I noticed that my oil temp gauge on my dash wasn't working. The needle was all the way to the left. I had been driving for an hour, so my car was at operating temperature. I pulled over, looked under the hood, listened and everything seemed okay. Nox Vidmate VLC No check engine light, codes etc. I made it home and drove it again yesterday, same thing. I have heat, car sounds fine, runs fine. I've tried to find some more info online, just can't pin it down. Could this be the oil temp sensor going bad? If so, is it an easy DIY? Where is this part located in car?

it's just not sensible to drive very much at all w/o being able to monitor engine temperature.

[bdragon46]

"Bump". Any updates on what the issue or issues were. I use MHD to clear the codes and the oil temp guage works as it should for the remainder of my commute. I know it's sensor related but not sure on which sensor to replace. I was told that the oil pressure sensor located by the oil filter housing also works as the oil temperature sensor.