[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. 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?

[HighlandPete]

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. 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?

First thing I'd try, is looking at the digital display via the hidden menu. Then you will know what the oil temperature is, or if there is a fault with the gauge. No digital display, likely a sensor issue.


Hidden menu, the one accessible using the code generated from the last few numbers of the VIN number. There are videos on how to access, if you are not familiar with the way in.

[Wgosma]

You can also run instr cluster self-test with hidden menu- that will rule in/out possible cluster failure.

You can also set the cluster to readout coolant temp in Deg C....have to do it each time you startup the motor but sure as heck a lot safer than driving blind/no engine temp info.

[cfm56d7b]

Do you have a code scanner such as Foxwell NT510? It's unusual for CEL not to turn on if a major component such as oil temperature sensor could be malfunctioning. There could be other codes stored.

[capocuoco]

Thanks everyone. I guess I'll look up the "hidden" menu & try that. I don't have a scanner, but I guess I could go to a auto parts store and have them scan it for a code. I'll try these suggestions and report back. I can work from home, but do you all think it's safe to drive locally until I can figure this out?

[Wgosma]

Don't drive the car again until you get the cluster unlocked so you can monitor either the Oil or Coolant fluid temperature (both are available via hidden menu....go to YouTube and search BMW F-Series hidden menu).

You don't want to overheat the motor, be smart on this and get that temp info displayed before you run the car even a few miles.

Codes: auto parts store may be able to read but not certain they will be able to interpret - you may well need a mechanic (Dealer or Independent mechanic) to assist on this. Or buy scanner and learn how to use it.

[jh_f30]

Regardless of whether it's the cluster or the sensor, I don't think driving moderately is an issue. I'm pretty sure there are cars out on the road that have neither an oil or coolant temp gauge. I see you're in Pittsburgh, so I'm guessing overheating won't be an issue. Check out the digital temp readout as others mentioned, and while you're at it, check your oil level if you can (I don't know if it'll even work given the current situation...another instance where a dipstick would be nice).

You should be fine driving to a shop or the dealer to get it checked out. Previous poster said "don't drive the car" but I don't think this is so severe an issue that would warrant suggesting you tow the car to get it checked.

[Wgosma]

You don't need to have the car towed; it's just not sensible to drive very much at all w/o being able to monitor engine temperature.
Good luck w/repairs / Bill

[capocuoco]

I found the "hidden" menu and ran the system test. The oil temp gauge needle moved & operated on that test. Everything else seemed fine. After my car idled for 7 minutes in my driveway (heat off, 35 outside temp), I shut it off and looked at the coolant and oil temps in the hidden menu. Coolant temp read -128C or (-198.4F) & oil temp 47C or (116.6F). The coolant doesn't seem right at all and the oil temp seems low but might be right as I wasn't actually driving, just idling. I'm going to run a few errands and I'll be driving a total of 3-5 miles. I'll re-test when I get home and report back. Any thoughts? Thermostat stuck open? Coolant sensor? Thanks to all for the help so far.

[Phoenix704]

Originally Posted by capocuoco

I found the "hidden" menu and ran the system test. The oil temp gauge needle moved & operated on that test. Everything else seemed fine. After my car idled for 7 minutes in my driveway (heat off, 35 outside temp), I shut it off and looked at the coolant and oil temps in the hidden menu. Coolant temp read -128C or (-198.4F) & oil temp 47C or (116.6F). The coolant doesn't seem right at all and the oil temp seems low but might be right as I wasn't actually driving, just idling. I'm going to run a few errands and I'll be driving a total of 3-5 miles. I'll re-test when I get home and report back. Any thoughts? Thermostat stuck open? Coolant sensor? Thanks to all for the help so far.

Coolant temperature seems alright to me. Remember, it's a high efficiency engine, and designed to run on the warm side.

I'd be curious about what the actual oil temperature was after driving for a little and really warming the oil up. If it starts to read over 160F and isn't registering on the gauge, than your issue is narrowed down something beyond the actual sensor. Not familiar enough with BMW electronics to say whether it's a cluster or some component in between the temperature sensor and the cluster.

[jh_f30]

Originally Posted by Phoenix704

Coolant temperature seems alright to me. Remember, it's a high efficiency engine, and designed to run on the warm side.

I'd be curious about what the actual oil temperature was after driving for a little and really warming the oil up. If it starts to read over 160F and isn't registering on the gauge, than your issue is narrowed down something beyond the actual sensor. Not familiar enough with BMW electronics to say whether it's a cluster or some component in between the temperature sensor and the cluster.

Oil temp of around 117F isn't operating temperature. I consistently read 240-250 on the dash gauge after driving around a bit. My coolant temp floats around 210-220. It usually takes up to 10 mins of running the engine under load (driving around, not just idling) to get it to operating temps. Given that you're running it in cold ambient temps, 7 minutes of idling isn't going to get fluids to the point where you might be able to detect an issue.

I'm still leaning towards there not being a mechanical problem, just a bad sensor, IMO. I would like to think that there are redundant safeguards in place should something go wrong. The car would likely go into limp mode to protect the engine if there was a serious issue. I can't imagine one faulty sensor being enough to cause catastrophic failure.

[capocuoco]

After doing some errands, I ran the tests again. Coolant temp same as before -128C or (-198.4F). Oil temp was 71C (160F). I was driving very conservatively, shifting @2500 or so. Maybe a wire running from a sensor? Any other ideas? I forgot to take it to Advanced Auto to run a scan. I know I should just buy a good scan tool. Any suggestion for that? Foxwell? I'll probably just bite the bullet and take it to the shop. I've been trying to do maintenance/DIY work on this vehicle as much as possible, but sometimes it's above my "skill" level.

[5mall5nail5]

Are you saying it is reading "negative" 198F? Does it change from that at all? Obviously "negative" temperature is never a good thing...

[Wgosma]

Seems the cluster checked ok- likely it's the oil temp sender signal.

Scan tool is decent investment if you are able/willing to DIY some repairs. Very helpful. You might browse BimmerLink app. - it's pretty good.

[capocuoco]

Originally Posted by 5mall5nail5

Are you saying it is reading "negative" 198F? Does it change from that at all? Obviously "negative" temperature is never a good thing...

Yes, it's reading negative 198. That's why I thought it might be the coolant sensor or a wire malfunction coming from it.

[5mall5nail5]

Originally Posted by capocuoco

Yes, it's reading negative 198. That's why I thought it might be the coolant sensor or a wire malfunction coming from it.

That's very odd. Most coolant temp sensors only go down to like -40F. clearly a fault there. prob zero resistance.

[Wgosma]

Originally Posted by capocuoco

Yes, it's reading negative 198. That's why I thought it might be the coolant sensor or a wire malfunction coming from it.

Is coolant reading 'stuck' at -198F or does the value vary? Problem is one of two places: sensor/sender or cluster.

Maybe you'd better run that instrument cluster self-test again and double check that it is fully functional. Looks like you have 2 issues: coolant digital reading and analog oil temp gauge, hmm...I'm thinking cluster issue-

Sounds like time to get fault codes read; have mechanic look this over.
Good luck/Bill

[capocuoco]

It seems like it's stuck at -198. Both times I've run the test, it read -198 and didn't change. Did cluster test again and oil temp gauge "needle" moves during the test. Frustrating, but I'll be calling the mechanic tomorrow.

[Phoenix704]

Originally Posted by capocuoco

It seems like it's stuck at -198. Both times I've run the test, it read -198 and didn't change. Did cluster test again and oil temp gauge "needle" moves during the test. Frustrating, but I'll be calling the mechanic tomorrow.

Highly unusual - as previously mentioned, sounds like a bad sensor. It's very possible that a bad coolant sensor is improperly keeping the thermostat open when the engine is cold, which would cause the car to warm up veryyy slowly. This could be the reason for the oil temperature rising slowly as well.

Do you have heat after a few minutes of driving, or does the air blow cold longer than it seems like it reasonably should?

My oil temp will usually settle right at 200, sometimes a bit higher if I'm driving spiritedly. If I'm idling, it tends to drop below 200. This is after 10-15 minutes of driving.

[dan of montana]

As others have said, buy a scan tool. I use a cheap OBDII + Bluetooth tool and it is great. That will help determine if it's a bad gauge. If it's a bad sender, you will still see the same junk values from the OBDII port.

Two other thoughts:
1. It's cold out right now, and it's not uncommon to see lower oil temps if you're just cruising around.
2. If your thermostat is bad, it would be stuck open and your oil temps will only come up after significant driving.

[HighlandPete]

Originally Posted by Phoenix704

Highly unusual - as previously mentioned, sounds like a bad sensor. It's very possible that a bad coolant sensor is improperly keeping the thermostat open when the engine is cold, which would cause the car to warm up veryyy slowly. This could be the reason for the oil temperature rising slowly as well..

Similar thinking, from the description posted.

Does appear that coolant is likely running cold. Faulty signal does seem likely, from the constant temperature reading. Cool ECT will prevent oil temperature from climbing as normal, particularly in colder ambient temperatures.

[supermarket]

Originally Posted by Phoenix704

Highly unusual - as previously mentioned, sounds like a bad sensor. It's very possible that a bad coolant sensor is improperly keeping the thermostat open when the engine is cold, which would cause the car to warm up veryyy slowly. This could be the reason for the oil temperature rising slowly as well.

If the car thinks that the water temperature is too low, if anything, it’d keep the thermostat closed, not open. That means that you’d get no coolant flow through the radiator(s), even when the water’s up to temperature. There’s a pretty bad overheating hazard.

But I think that the N55 thermostat isn’t strictly electrically controlled. It does have an electrical connection, but I think the thermostat is primarily a mechanical device with electric input to tweak its operation. That makes a huge difference here. Probably no overheating risk. Probably.

The B58, which replaces the thermostat with a “heat management module,” would be a different story.