JBotone - Thanks for the how-to guide! Could you please edit step 16 to say a 19mm or 3/4" wrench will fit the sensor, since 3/4" is within a hairs width of 19mm. I don't own a 19mm wrench, but I do have a 3/4" wrench and remembered from various past encounters with 19mm nuts and bolts that my 3/4" wrench fits nice and snug. Thankfully, I remembered this before buying a wrench I didn't actually need. By the way, I have my Tousley receipt in front of me and I paid $104.15 + $10 shipping ($114.15 total). Also, be sure to mention special internet pricing if you order by phone. The brass plug should be 1/8 inch pipe thread. When I brought my housing into the hardware store, the 1/8 inch would only thread in 2-3 turns by hand before tightening up. However, once you get the Teflon tape on it, it will turn smoother into the extra port. Also, I found a counter sunk 1/8 inch pipe thread brass plug that IMO looks and works the best. The plug is just over 7mm tall and fills the extra port neatly without sticking out. I will also list the part numbers as a convenience to anyone checking out this thread.
F8RZ 8592 AG - Thermostat Housing
F5RZ 8592 A - Thermostat Cap
F8CZ 12A648 B - Sender Assembly
W500015 S309 - Screw
(requires 3 of these)
W700319 S300 - Thermostat O-ring
F8RZ 8575 CA - Thermostat