1979 240D 123 616

my oil pressure is pegged. when off, it is 0. as soon as it starts, it goes right up to the top (during idle). Perhaps this is because it's cold, i changed the oil 2 days ago, always was lower during idle, maybe because the oil was so old.

i cleaned the contacts at the two senders, one i know was the temp, but then i looked in the dash and it's a mechanical guage, looked like an oil fitting on the back of the guage.

any ideas? could the guage be broken? is there some way that something is plugged doing this? it was pretty darn hot when i was doing the checking after i got home from work, still pegged at idle.

thanks!