300 tdi running hot

[Oberon 110]

Hi all, my 300 tdi appears to be running hot. It's runs for around 15 minutes or so, but then the gauge goes up about 3 quarters to max. My lr specialist hasn't found any issues, although the ac doesn't work so I wonder if the fan not running is blocking airflow? Another interesting thing is that if I turn the ignition off and then immediately back on, the gauge returns to a healthy reading, so possibly a temp sender issue. Any ideas or advice would be appreciated very much! Cheers

[Red90]

Most likely an electrical issue. High reading means an issue on the ground side. Check engine grounds, main harness ground and gauge ground.

Buy an infrared temperature gun to verify engine temperature. They are cheap and accurate.

[Robmacca]

Hi all, my 300 tdi appears to be running hot. It's runs for around 15 minutes or so, but then the gauge goes up about 3 quarters to max. My lr specialist hasn't found any issues, although the ac doesn't work so I wonder if the fan not running is blocking airflow? Another interesting thing is that if I turn the ignition off and then immediately back on, the gauge returns to a healthy reading, so possibly a temp sender issue. Any ideas or advice would be appreciated very much! Cheers

I had something very similar with my old Tdi300. I determined mine was due to water ingress as I had been through quite a bit of water and there was no way the engine was as hot as the gauge was telling me. Did all the normal checks and just put it down to water ingress. The following day after everything had dried out all was back to normal.

It might not be related to your situation though...

[shack]

Another interesting thing is that if I turn the ignition off and then immediately back on, the gauge returns to a healthy reading, so possibly a temp sender issue.

Mine does exactly the same, once it reaches a certain point on the gauge, it
will continue to climb irrespective of temp.

I checked the head temp at the sensor with an IR thermometer and was pretty sure the gauge was reading wonky compared to the thermometer reading, so I bought another stand alone digital gauge and left the original in place.

The digital gauge confirms over a few years that the original is faulty, but I never tracked why, gauge, sender or earth.

I'd fit another gauge if it was me.

[Oberon 110]

Thanks for your respones everyone, much appreciated. Sounds like it's almost certainly an electrical issue. Should be an easy fix to sort out the grounding issue. Cheers