Last winter I wanted to use the D6 to plow the deep snow out of the driveway. It was 10 above F. The oil pressure did not budge and after sweating for what seemed an eternity and was no doubt too long I shut down.
I received several suggestions including that it might be the gauge. I finally tackled it the other day and it was indeed the gauge, but in a surprising way. Inside the crystal (is that what the see-through cover is called? there was a ton of moisture. Obviously the moisture had frozen, preventing the needle from moving. thank heaven that was all it was! I had worried all winter that I had damaged the diesel by cranking it too long with no oil pressure.
I put the gauge in the oven on low temp thinking to boil the moisture out but not realizing that the crystal is not glass but some kind of plastic and it was cooked. Fortunately I had a NOS gauge on hand that I had got off ebay several years ago on a whim and it works fine.
The D6 has plenty of pressure now and purrs like a kitten.
Whew!

 

Yikes! not again.  I give up. this website and i just don't get along!