Thermostat Choices in 2025

[t36]

So I'm looking for the best thermostat options in 2025.

Clark's and a few Vendors list:

944 106 019 00 - for the new style turbo pump.
Opens at 83 degrees.

One Vendor sells:
944 106 129 05
-this appears to be for the older model pump.
But they say it opens at 80 degrees and is applicable for all models.

I purchased both Wahler units. Both of them are stamped made in Brazil rather than Germany.
Reading old posts it appears a 71 degree thermostat gives good results. I cannot find a part number for this unit however.

Between two options above, is one a better option for the 944 turbo with new style pump? Should I keep hunting and find a Made in Germany Wahler?
thanks!

[Tom]

Wahler was acquired by BorgWarner maybe a decade ago, and was essentially folded into their branding and mfg infrastructure. BorgWarner then sold it to another company, TMS, which brought back the name, but seems to make the actual thermostats in various countries. In other words, unless you find a NOS vintage Wahler, they aren't the same these days. That's not to say they are bad, I'm just not sure they are the gold standard anymore.

You need to see if you have the new or old style water pump (most are new style by now) and then get the t-stat that fits your pump. If you have an old-style pump, consider changing it! As for temp ranges, what is the climate where you live? In climates with hot summers, I'm a fan of the lower temp thermostats, paired with a lower-temp radiator fan switch.

[walfreyydo]

I just went through this and if you dont get the right thermostat to match the pump style it wont fit right. I referenced clarks garage for this info to be sure I got the correct thermostat:
https://www.clarks-garage.com/shop-manual/cool-07.htm

On the newer style water pump, the gap between the thermostat sealing surface and the snap ring groove is 7mm. This will require the newer style thermostat and sealing ring. It will also require installation of the 2.5mm support washer between the snap ring and the thermostat. The older style water pump has a 4.5mm gap between the thermostat sealing surface and the snap ring groove and requires the older style thermostat and sealing ring without the support washer.

The correct thermostat part number and correct snap ring is listed in the table.

What temp thermostat you get doesnt really matter as long as its a lower temp than the radiator temp switch installed in the radiator. If the temp switch is lower than the thermostat opening temp, the thermostat wont ever open (because the fans will switch on before that point and keep the coolant temp too low for tstat to open).

However, this usually isnt a problem as the OEM temp switch triggers at 92C, but there are some that trigger lower I believe, such as this one which triggers at 85C allowing the car to run cooler while sitting in traffic. Also note that later model cars run a dual activated temp switch for high/low speed fan control (92C/102C), whereas early cars only have a single switch control (92C), but again, a previous owner could have changed to a different, possibly lower temp, switch.

[t36]

I just went through this and if you dont get the right thermostat to match the pump style it wont fit right. I referenced clarks garage for this info to be sure I got the correct thermostat:
https://www.clarks-garage.com/shop-manual/cool-07.htm

On the newer style water pump, the gap between the thermostat sealing surface and the snap ring groove is 7mm. This will require the newer style thermostat and sealing ring. It will also require installation of the 2.5mm support washer between the snap ring and the thermostat. The older style water pump has a 4.5mm gap between the thermostat sealing surface and the snap ring groove and requires the older style thermostat and sealing ring without the support washer.

The correct thermostat part number and correct snap ring is listed in the table.

What temp thermostat you get doesnt really matter as long as its a lower temp than the radiator temp switch installed in the radiator. If the temp switch is lower than the thermostat opening temp, the thermostat wont ever open (because the fans will switch on before that point and keep the coolant temp too low for tstat to open). However, this usually isnt a problem as the OEM temp switch triggers at 92C, but there are some that trigger lower I believe, such as this one which triggers at 85C allowing the car to run cooler while sitting in traffic. Also note that later model cars run a dual activated temp switch for high/low speed fan control (92C/102C), whereas early cars only have a single switch control (92C), but again, a previous owner could have changed to a different switch.

This is all great info.

I have an updated water pump already and I’m putting in a brand new GEBA unit.

I might opt for Mahle/Behr. Combo of temp switch and thermostat. They both appear to be made in Germany still and temps seem to cooperate.

Very interesting that the vendor says 80 degree old style thermostats work for the new style pump.

[walfreyydo]

Yes this is why it is advised to measure the distance between the snap ring groove and sealing surface just to be sure. There are many different iterations of water pump out there now and the key indicator of what thermostat to get is that distance...

[t36]

Wahler was acquired by BorgWarner maybe a decade ago, and was essentially folded into their branding and mfg infrastructure. BorgWarner then sold it to another company, TMS, which brought back the name, but seems to make the actual thermostats in various countries. In other words, unless you find a NOS vintage Wahler, they aren't the same these days. That's not to say they are bad, I'm just not sure they are the gold standard anymore.

You need to see if you have the new or old style water pump (most are new style by now) and then get the t-stat that fits your pump. If you have an old-style pump, consider changing it! As for temp ranges, what is the climate where you live? In climates with hot summers, I'm a fan of the lower temp thermostats, paired with a lower-temp radiator fan switch.

Oh wow. Yep I have an updated one currently and switching it out for new GEBA one.
I’m in the PNW, but we get really hot summers nowadays in the valley and that’s really the majority of my driving season. Do you happen to know the part numbers of the lower temp switches? I can’t find them in the PET or google searching.
Thanks Tom!

[walfreyydo]

Thermofan temperature switch:

Late Model: 951 606 481 00 (85C linked in my post above)
Early Model: 823 959 481 (there appears to be some as low as 70-75C so be wary when pairing with your desired tstat)

[t36]

Thermofan temperature switch:

Late Model: 951 606 481 00 (85C linked in my post above)
Early Model: 823 959 481 (there appears to be some as low as 70-75C so be wary when pairing with your desired tstat)

Thanks!

[Latitude48]

I have a new Porsche thermostat 944 106 019 00 I purchased in 2022 for an eventual pump replacement. I'll dig it out and see where it's made, and if it has any temp markings.

[t36]

I have a new Porsche thermostat 944 106 019 00 I purchased in 2022 for an eventual pump replacement. I'll dig it out and see where it's made, and if it has any temp markings.

Awesome! Appreciate that.
My recent purchase from Pelican indicates Made In Brazil and stamped 2022.
My local dealership is bringing one in as well to check. Maybe they have old stock.