Which thermostat?

[Error404]

Thats pretty much what mine is doing. It will get to ~90° at a standstill, taking a bit longer than usual. Once on the move the temp drops quickly to ~60°. Using quite a bit of fuel as a result.

[Jamo]

Are you going by the gauge or ECU via vagcom? as that sounds like a temp sender fault, I had that at one point, the ECU reads from a different sensor IIRC Now S2central.net is back you can ask him.

[Error404]

I checked with measuring blocks in VAGcom and ECU was reading similar (from the sensor on the back of the head)

[Jamo]

Thats good to know then that it's not a temp sensor issue, the only other thing is the clocking of the stat, but they have been known to fail especially the gsf aftermarket ones

[Bowie69]

Cheers Alex, it's the same part no for a 7A as well, just confirmed in parts cat

[Human Joist]

Sorry. Mistyped the entry as phone playing up. The mfts was £50 half price. From memory the thermostat was around the £12 mark from QC

[AndyP]

I've had nothing but problems with non-genuine ones ( GSF and ECP supplied ) so I always splash out and get a Wahler from the dealer, not cheap at almost £20 but never had a problem.

Any idea what difference clocking them makes as I never knew about this before??

[Bowie69]

Without looking it is likely to be a bleed hole to allow air or steam to pass through and stop air locks forming as the thermostat sees a lower temperature.

Also aids filling.

But there may not be a hole

[Error404]

There is a small hole
I think it also helps the coolant to circulate around the block & head preventing hotspots

[johne]

You don't want a thermostat with a small hole in it like the Frusser ones from GSF because if there's even a small hole your temperature will fall away cruising on the motorway in the winter.

Small hole with a jiggle pin to close it like some Wahlers is fine.

John

[JariP]

I had this same problem with temp gauge readings, changed the thermostat (Wahler) and still the gauge reads low as before. I recommend checking the temperatures with a laser temp gauge or thermocouple before changing the thermostat. Water hose going from head to heater matrix might be a good place to start measuring the temps.

[DNA-S2]

I will be trying out some that they open at 71C on my current builds
Like the idea of water/coolant exchange earlier

[AndyP]

I know that if there is a hole you put it at 12 o clock, but I'm 99% certain that the Wahler ones don't have a hole

[Error404]

I had this same problem with temp gauge readings, changed the thermostat (Wahler) and still the gauge reads low as before. I recommend checking the temperatures with a laser temp gauge or thermocouple before changing the thermostat. Water hose going from head to heater matrix might be a good place to start measuring the temps.

How did you resolve the issue Jari?

[Thuppu]

I did resolve a similar problem(low gauge reading) with a new multi-sensor.