Temperature gauge shot up

[agapebmw]

This morning I had a problem starting the car as it was -22F and when I finally started it my temperature gauge shoots up to the red zone. I got scared so I turned off the car immediately.

I came home and started the car again without any problems (it got warmer). Now the temperature gauge still jumps right to the red zone (all the way to the right). There is no way that this is right as the engine is cold.

I just let it idle to hope that temperature is gonna come down to correctly display...but it's pretty much stuck there.

I turned it off and started again. The gauge actually sits where it should be for about a sec and jumps right to the red zone again...

Does anybody know what the problem is?

[Damaskus325]

Sounds like a bad thermostat. DO NOT drive it until this is fixed. That is a sure fire way to blow your head gasket.

[Cyrix2k]

does it go up immediately after you start it? Probably the temp sensor then, def not the thermostat if it goes up immediately. Even if it were stuck closed, it would take a while for the car to warm up.

[bmwtuner325is]

easy way to tell.....turn the ignition on but leave the motor off, (with the motor cold) if the needle still pegs to the right the temp sensor is bad....if not then its your thermostat and you need to follow the advice given and not drive it

[agapebmw]

does it go up immediately after you start it? Probably the temp sensor then, def not the thermostat if it goes up immediately. Even if it were stuck closed, it would take a while for the car to warm up.

Yes it goes up immediately even after the first start up.
I thought the same thing. If the t-stat failed at closed position it should take a while for the car to warm up especially in this 5F or colder weather.

easy way to tell.....turn the ignition on but leave the motor off, (with the motor cold) if the needle still pegs to the right the temp sensor is bad....if not then its your thermostat and you need to follow the advice given and not drive it

Yes it pegs to the right.

It's funny how it correctly displays for about a sec and pegs to the right. Would it still be the temp sensor?

[Doc325i]

unplug and then reinstall the sensor atop the thermostat housing. Sometimes that will do it, if not, a new sensor is needed.

PS: Fill out the General information, which E39 is 'Nightkid'? Listing the car helps us help you better.

[agapebmw]

unplug and then reinstall the sensor atop the thermostat housing. Sometimes that will do it, if not, a new sensor is needed.

PS: Fill out the General information, which E39 is 'Nightkid'? Listing the car helps us help you better.

Are you talking about #16?

[Aussie528iT]

You can also do an instrument panel test to test the operation of all the instruments in the cluster.
Do a search on accessing/unlocking the instrument panel. (depends on which panel you have, high or low BC, for accessing/unlocking)
Test 2, which can be accessed without unlocking the instrument panel, will test all the individual instruments. If the temp gauge tests OK then its probably the sensor.

RonR

[Doc325i]

Which E39 Model do you have???????? Include this information in the spot where you list 'nightkid' as cars.

I am talking about the sensor atop the thermostat housing, not pictured in the diagram you added.

[agapebmw]

I actually have a 04 Range Rover which has a M62 4.4L engine. Since the range rover forum sucks, I had to come here. The below is extracted from Wikipedia.


M62TUB44

In September 1998, BMW introduced the M62TUB44, including within it the VANOS system and an electronically actuated throttle. Each bank of cylinders included a single-stage VANOS system, and only on the intake valve timing (not the exhaust valves). In contrast, the M52 6-cylinder included dual VANOS with the "TUB" moniker.
The engine design also included slightly larger mass-airflow sensor and lower flow intake plenum runners which improved lower RPM torque characteristics at the cost of some high-rpm flow. Non-"TUB" intake manifolds can be transplanted onto a M62TUB44 engine to improve high (>3400) RPM torque and power characteristics (similar in effect to the swap of OBD1 manifolds onto newer OBD2 generation M52/S52). Dinan also sold this modification under a Dinan performance package (but the BMW part numbers are equivalent to stock -B44 manifolds).
210 kW (286 PS; 282 hp) and 440 N·m (325 lb·ft) / Electronic Throttle -SINGLE vanos;the M5 S62 was the first BMW V8 (and only E39 V8) with dual vanos. In 2002, the power was increased from 210 kW (286 PS; 282 hp) to 216 kW (294 PS; 290 hp) while torque remained the same.

1998-2003 E39 540i
1999-2001 E38 740i/740iL
1999-2003 E53 X5 4.4i
2003-2005 Land Rover Range Rover 4.4
2000-2004 Morgan Aero 8 Series 1[1]

Which E39 Model do you have???????? Include this information in the spot where you list 'nightkid' as cars.

I am talking about the sensor atop the thermostat housing, not pictured in the diagram you added.

So you are talking about #9 in the below diagram.

[Doc325i]

13621703993

[agapebmw]

13621703993

Thank you sir!

[agapebmw]

Just to give you guys an update.

My battery was dead, so I removed and recharged the battery. I started the truck again when it got much warmer like -5. The gauge problem is now fixed!!
In the end, I didn't have to replace anything...and I still don't know what happened...

[NoTempoLimit]

I've had a similar thing happen with my M52TUB28. The temp gage quickly rises to the red zone.

It always happens during very slow driving where you would not normally expect an overheat. In each case I stop the car and open the hood and the engine is not any hotter than normal.

Usually, checking after the engine cools off, there is not enough coolant in the expansion tank. I think it's some kind of air bubble that causes it, and I try to bleed the system each time it happens.

I think I've got some kind of very slow coolant leak that can't be detected by the usual means. Systems holds pressure and does not leak coolant.

[keefy6]

hpend to me called my mechanice and discussed that it was one of two things. thermo or low coolant. added coolant maybe twice and it was fine. obviously don't drive it, but try the coolant if you haven't first, start and see if it goes up and stays up. DONT DRIVE just start, if the engine beginst to heat up, the guage moves without having to move the car.

[tdubbs211]

Need Help! Mechanics just taking my $ and not fixing problem. They scanned the engine while it was running and confirmed it is not overheating. My gage still jumps all the way to right, sometimes comes back normal, sometimes does not. Any suggestions helpful! 97' 528i

THnx
Tdubbs

[Gregs///M]

Need Help! Mechanics just taking my $ and not fixing problem. They scanned the engine while it was running and confirmed it is not overheating. My gage still jumps all the way to right, sometimes comes back normal, sometimes does not. Any suggestions helpful! 97' 528i

THnx
Tdubbs

There's a short in the signal wire. Once the signal wire from the sender is shorted, the gauge will peak to red. Replace the damaged section.

[mattmartindrift]

There's a short in the signal wire. Once the signal wire from the sender is shorted, the gauge will peak to red. Replace the damaged section.

as said, it's either a bad sensor, a bad connection to the sensor, or bad wiring.

When the DME sees a fault in the sensor circuit, it defaults the thermostat to full-open, and pegs the temp gauge in the dash. If you unlock the OBC, and run Test 07, you will see that it reads -40ºC. -40ºC is pretty darn cold.

[dluker]

I accessed the DME with my computer, cleared out the fault code, and the temperature gauge is back to normal. No shorts, no bad sensor, no bad wiring.

[trent740il99]

I have the same problem with my 99 740il , could I cracked coolent line cause this problem . Were the temp guage shoots to the red right away?

[mxracer41]

If the gauge is shooting straight to the red that quickly I could almost guarantee you it's your temp sensor (as long as your wiring and everything is good). Mine went bad on my 540 and that happened to me a few times and scared the hell out of me. Replaced it about a month or so ago and haven't had an issue since.

It's really easy to replace; it sits right on top of the water pump and all you need is a big socket (forget the exact size), screw it out and screw the new one in and plug it up, boom you're done. You'll lose a tiny bit of coolant but that's about it.

[e31gixxxer]

Any updates on this subject, same issue on our new 540i.

[e31gixxxer]

Does it every day after a few miles from cold start. Needle is full hot even if the car is left for 2hrs or even over night.
Battery disconnect is the only reset, then its fine until next days cold start.
New dual temp sensor fitted and same.
Several codes including coolant temp sensor, EWS random code storage, supply voltage constant.
Live data on scanner shows temp and sensor voltage are stable.
New stat ordered but can't see it being that, although lots of accounts of this fixing other similar issues. Left the heater unplugged incase a heater fault was dragging the temp readings down, same.
Looking like an inspection of the wires and DME when time allows.

[joeappel]

@e31gixxer - is it just the temp gauge? Or does the tach not work and the DSC light come on, too? If so then it's likely the DSC module.

[e31gixxxer]

Joeappel, just the temp gauge nothing else and just the first start of the day.
It didn't do it today after being parked at work for 8hrs, but did it on the way there after a long cold night.
We will change the stat on Sunday and see what happens, not holding my breath.
There is also the bottom hose sensor. I only see one coolant temperature and sensor voltage on my scanner, so there are another three temperature inputs to the DME. The two on the dual sensor, the bottom hose one and one on the rad r/h top.
I can't help thinking The DME is either not getting some of that data or doesn't like what it sees.