Thermostat Mahle or OEM Volkswagen

The thermostat I pulled out was probably original, but wasn't stuck. After replacing the timing belt and thermostat, I filled the car back up with coolant and started it up. It did come up to operating temperature quicker

I replaced mine with a low temp thermostat and low temp fan sensor aswell as the infamous blue coolant temp sensor a week ago and everything ran so much cooler and smoother now. My coolant temp sensor failed for weeks and wouldn't run the low speed fan and the water temp was 30-40 degree hotter than usual. Now it's all good with AC blasting in bumper to bumper traffic for 1 hour and it water temp reads 205-215, but my oil are in the 240's.

The thermostat and temp switch are cheap. To clear up a misconception, your vehicle will come to operating temp if you use a 'low temp' unit.

I'll throw a lower temp thermostat see if I can get her temp to stay low as possible for now

I had my water pump and thermostat changed in August under warranty. I went for an oil change in Dec and they told me they think the thermostat is leaking. I told them they just replaced it 4 months ago. They went back and cleaned up the area around the thermostat and oil pan and said we need to monitor it to see if it's really leaking again. They were not surprised when I asked if it was possible it could be leaking again. They told me they see the part fail all the time.