Hey guys i have recently purchased a NF Fairlane with a 5 litre in it, and i am having trouble with the oil pressure gauge. I have changed the oil and put a new filter on it, but the gague reads that i have no oil pressure.
On startup on a cold morning the gauge hardly goes up to the halfway mark, then as soon as you start driving it goes down until the warning light comes on. The car still runs fine, no knocks or ticking or clunking. Could the oil pressure sender be crook??

Yep change oil sender unit and check motor to body earth, connections at bettery....