Hi Fabs, it will be npt, most temp senders are 1/8th npt but usually the sump has different size like 1/4npt so you need an adaptor to fit it
cheers Richie
ritchie it seems that the vdo temp senders is M10 x 1
I haven't used one of those in sump, when i used vdo it was the dual temp and pressure sender in stock pressure location