Is my oil temperature sensor faulty? - SOLVED

[Auspinks]

I've recently noticed that the oil temperature shown on the MFD seems to be a little erratic.

The temperature will work it's way up to around 100-110 and then it can spike upwards. Sometimes it'll jump to 130 (I saw a 140 spike today too!) and then a second later back down to 110. The average temperature seems to be a little high for my liking but is due an oil change soon so I think that may help?

Could these spikes in temperature be a sign of a faulty oil temperature sensor?

As a side note, is there an actual temperature sensor? Or is this sensor part of something else? I can't seem to find the sensor itself online.

[blower]

The spikes could be a sign of a faulty sensor.

The oil temperature sensor is integrated into the oil level sensor that's on the bottom of the sump.
If you give me your engine code and year of manufacture i'll look up the part number for you.

[Auspinks]

Cheers mate! I was thinking it may be combined inside that unit.

The model is a 2009 GT TDI 140 (I think this is a CBDB?)

Also I don't suppose if the temperature spiked up massively that it could trigger an engine warning and limp home mode to be activated?

[blower]

Part number for CBDB engine is 1J0907660F

Too high an engine oil temperature will trigger an EML and limp mode - especially if its jumping around erratically, it will log a fault.
If you have had this it's best to get the car scanned to check what faults have been logged and confirm a sensor problem - it is looking like a faulty sensor, it could be a wiring/connector fault so best check the connector to it as well - make sure its clean and not full of oil (not that it should ever be, but you don't know what clown has been messing around with it)

[Auspinks]

So today we took the car up on the lift to have a look at the sensor.

The sensor number is, 1J0907660C rather than F. I double checked the engine code and it shows 'CBD' which I assume is the same CBDB as I quoted before?

The car was left to idle on the lift with the bonnet open and the oil temperature peaked at 122C on the MFD and then dropped to 60C. Something very odd going on there! Tried jiggling the wires going into the sensor which didn't seem to make any differences and also tapping the sensor with a hammer. Again nothing seemed to change the numbers.

The sensor itself looks to be in good condition. (I'm doubting if the sensor has actually been there since new). Is 1J0907660C interchangeable with 1J0907660F? The actual fit of the sensor is good and the plug obviously fits just fine. I suppose the next step will be to change out the sensor but which should I go for C or F?

[daves2369]

The last character is usually just a revision code F newer than C

[Auspinks]

Update - Problem Solved!

So I decided to buy a cheap version of the sensor on eBay. Obviously it didn't work. We ran some diagnostics on the sensor and it was reading something but for some reason the car just wasn't accepting the part. (The eBay listing showed the same replacement part number but nothing was printed on the sensor like with the OEM part). After running the car for a few minutes the OIL SENSOR workshop light flagged on the dash and would not go out.

I then bought the OEM F version part the day after and the oil temperature now gradually increases up to around 92C which seems to be spot on. (No warning lights now either.)

Thanks to blower for his help with this.

DON'T BUY CHEAP EBAY PARTS! (Or at least an oil level/temperature sensor at least...).

[blower]

Glad you got it sorted

[Roy_01]

Nice!

[chelspeed]

but which should I go for C or F?

I was really tempted to suggest one's fahrenheit for the US market and the other's celsius for the European market. But then thought the sensor would be the same and the gauge would just display two different readings. Bit of a coincidence that a temp sensor has two versions, c and f, though. Glad it's sorted.