Does anyone else cringe at the installation of the extention hose with SAE threads into the engine case that is metric? The VDO extention hose has SAE threads on the end that screws into the case and you can see the difference in the pitch of the hose and a stock single pole OP sending switch. I really don't like the idea of possibly damaging the threads on the case, even to the point of not installing the gauge, but I guess there is no other option is there?

Jim, you're absolutely right to be worried about damaging the threads. Do not screw up the threads. That fitting is leak-prone enough even with perfect threads. If you go gorilla on it and force the fitting in there, you'll never get it to seal. Go to a hydraulic supply place and get them to make up a line with proper fittings. Or maybe contact King George at AA. I think he's got the lines in stock.

Goto a Paintball shop they have the 10mm x1 hoses or call Jake and order
one from him.
Tip
To install the hose goto a hardware store and get a set of open end
press sockets these will fit over the hose and let you tighten it. They
look like a pipe with sockets press in each end.

Here's the "real deal". The T1/T4 cases are tapped to a 10mm tapered thread not found in regular metric hardware. It's COMPLETELY compatible with 1/8 NPT. The handiest source for the hose you need is a grease gun hose, sold nearly everywhere auto parts are offered for sale. If you're using an electric sender, and you should be, you'll need to ground the body of the sender in order for it to work. 10mm x 1 threaded hoses are used in applications where a copper gasket is required, and that doesn't appear on VW/Porsche cars until about the time their waterpumpers came to the marketplace.

The Cap'n, who you can listen to because, unlike many others, HE KNOWS.

All hail the TRUE King ... Cap'n Krusty

Hope to see you at "used to be Dunkles" Cap'n. I'll be wearing my abestos underwear.

OK, so here's what I decided to do and I'm stickin' with it. It's reassuring to know about the tapered thread and the compatibility that the Cap'n stated. I didn't want to crank down on the tightness like davesprinkle stated so I took some teflon tape which basically was like a thread, not a ribbon like when you take it off the roll. and wrapped it around the threads in the middle of the fitting. I was thinking it would both give some sealing and make it so that I wouldn't have to tighten the hose too much. I tightened it by turning the hose then took some long nose needle nose to try to tighten some more. I mounted the dual sender to a hole on the fan shroud and made a short extension wire to reach from the female spade green/red wire in the harness to a ring fitting over the G pole on the dual sender. If anyone ever gets interested if it works and doesn't leak, I can let you know but.... the car is still on ..... jack stands and awaiting brake bleeding and rocker re-install. Waiting for the weather to break. See ya at Hershey!