hi rusty wrench, i used plumbers tape on the sensor, i thought that would help isolate the sensor from any potenital earthing issues.

both sensors were used, and had worked well, but the spare always sat at 3/4 temp were the one that i replaced it with sat at the correct 1/2 temp.
they both could have gone bad- being 2nd hand. unlikely though.

i get the copper loctite bit, didnt think it was suitable with coolant? glycol.

im running a L16 in my b110, no a series push rods here.

further advice welcomed.