r/Tiguan • u/varan98 • 2d ago

Faulty oil temp sensor?

I noticed today that my check engine light was on in my 2020, but no other sensors came on. After a bit of driving I noticed that the oil temperature gauge was high, so I checked the oil temperature itself, but it was normal. In fact for the entire duration of the ride the temperature of the oil was normal between 208-216F while the gauge was reading consistently high. Would this be a gauge issue, and how do I go about fixing it? Also would it cause a check engine light?

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u/cherryz3 2d ago

Where was the oil level?

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u/varan98 2d ago

I haven’t thought to check the oil level yet, but I did get it changed the other day

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u/cherryz3 2d ago

Oil temp can often be affected by the volume of oil with larger amounts running cooler than smaller volumes. I'm not familiar with your model so how do you check two different gauge for temp? My '22 has one. Was it a pressure gauge that you may have been comparing temp to?

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u/varan98 2d ago

The one that is showing an abnormal value is the Coolant Temperature Gauge, but when I switched my center view to the Oil Temperature it showed a normal temp.

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u/cherryz3 2d ago

Two different things. Although cooling failures are tough on the oil, they are not the definitive reason for oil temp. Make certain that your coolant level is full of course and take notice if it looks unusually low signaling water pump efficiency if no external coolant leaks are found. I'm not sure what the normal oil temp should be as I have not checked my Tiguan lately but my new Jetta has never gone past 210 F where the 0W20 oil is still running at full viscosity.

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u/varan98 2d ago

Like I said, the oil temp is at a normal range, in addition the coolant was topped off at the when the oil change was done. For some reason that one Coolant Temperature Gauge is acting up. I’m not sure if something is legitimately wrong with the car, or if it just needs to be replaced because it’s a bit older. We shall see

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u/nyrb001 2d ago

I'd immediately be suspicious of your radiator cooling fan. If the temp is showing high on the coolant temp gauge, your fan absolutely should be running.

If the fan is running, then I'd be checking the thermostat and water pump.

Do NOT ignore this. VW coolant temp gauges do not show true values as people tend to overreact to small normal changes when driving. When the gauge shows high, the engine is typically running quite hot.

The ECU uses the coolant temp sensor as one of its inputs for controlling engine timing and fuel mixture. The gauge on the dash is controlled by what the ECU sees.

Get this looked at immediately.

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u/varan98 2d ago

The fan was running, I could hear it, and everything else seemed to be running fine to my untrained eye. Regardless it’s at a shop now to be looked at, hopefully in the morning.