[Joe Bob]

I have never tested an internal thermostat like that but I would consider using an oil based liquid that doesn't boil at a low temp as water.

T-stats are cheap. Replace it if you have doubts. Do you have an external t-stat and a trombone or cooler up front? If so, did you do a read on the temps in the external lines?

A good hand held pyrometer is a good tool to verify oil temps. VDO gauges aren't always right. T-stats should open at 185ish F. Unless doing 'spirited driving', oil temps should stay around 175-190F.

If after re-installation, with a new internal t-stat and you still show hot on the gauge AND you verified the reading AND you don't have an external cooler.....consider one.

If you have a trombone AND the external t-stat in the wheel well is opening at 180F, consider a brass row or Carrera finned cooler.....