It's an odd thread, used for sealing small stuff with a taper. The thread in the case is straight-sided M10 x 1.0, the sender has (or should have) an taper. As you nip it up, the taper seals against the straight thread. By coincidence, it's almost (but not quite - thread pitch is slightly different) the same as 1/8" NPT.
It's a b*gger, on further investigation there must be half a dozen variants of the VDO pressure sender. Mine is marked 30/2, which at first seemed to short a number to be a real part number. But whaddya know...you live and learn.. https://www.vdo-instruments.com/pressure-sender-80-psi-warning-contact-7-psi-m10x1k-30-2.html M10X1 looks to be the chap, thanks.
That should be fine (you can see the taper in the pic), but it's 80psi full scale. Bit too high for an aircooler, if that's what it's going in.
Yes, air cooled, type 4 engine, 5 bar sensor. Blummin' minefield this has turned out to be. Bit disappointed with Machine 7, they usually supply good parts and good advice.
How’s Para getting on with his Vernier Caliper? His Vernier Caliper I say. How’s he getting on with it?
I went to school with Tobias Vernier Caliper. Nice chap, always good fun in the Prefects Common Room when we were thrashing the junior boys.
Related by interbreeding I believe. They had their American cousin over once, nice chap R Chet Screwdriver.
A 5 bar gauge (and matching sensor) is fine. Your oil pressure's going to top out at about 3bar (~42psi) in normal operation.
