Before you install your oil thermostat, you should find out if it works correctly.
An Oil Thermostat is an integral part of your Porsche air-cooled engine. Without proper oil flow, your engine will not be “air-cooled”, more like oil burnt.
Testing your Oil Thermostat
If you take a look inside, you can see a number stamped on the brass cone inside. This is the temp that the thermostat opens up at. Also, the unit has to close when cooled. The heat is not exact, and a 10% heat range on either side is acceptable.

Heating the Oil Thermostat
We use a hot air gun to heat the oil thermostat. We use a Raytec non-contact tempurature gun to read the temps reached. After we have confirmed the function, we are going to let the thermostat cool off!




When your oil thermostat is room temp you can put on the oring. When it gets in the slot, make sure there is no tension in the oring and it is not bound up in any way. We like to use a silicone lubricant to help as you press the thermostat into the case.
We have seen a few engines with silicone sealant on the thermostat. This is not how to fix a leaking oil thermostat. This is very bad. All of the oil will pass through this point, and contamination here can destroy a Porsche engine.

Other Oil Fittings
With the oil thermostat functioning and in place, we can move onto some other oil fittings. Again no sealant. A copper or aluminum crush washer is all that is required. Remember that these washers are a one-time use, so do no use them again!
Oil pressure sender
Earlier we put in the adaptor for the oil pressure sending unit. Depending on your model there can be different oil pressure sender types here.
Oil Temperature switch
Clean and test the temperature switch before installing it. Use a copper or aluminum crush washer in this spot too.
Camshaft oil line fittings
We continue with a couple more oil line fittings for the cam shaft oil feed lines.
With all of these oil parts, no sealant, fresh seal rings, not too tight, and you will be good to go.
Up Next on the Engine Build
Thanks for watching and reading about your Oil Thermostat.
Up Next, we tackle the timing chain guide rails. There are some tricks to learn here, as the timing chain guides can go in the wrong way, the wrong depth, or the wrong type! Continue to follow along with us and learn what to do to be confident in your air-cooled build.