I've got a government John Deere 444JR diesel that runs fine but has to crank for 20 seconds or so to start. I can watch the oil pressure sit at zero all through the crank but as soon as it pops up, the truck starts right up. So I'm thinking that the oil system is draining back into the sump between starts. Oil pressure is good once it starts.
Does anyone know of a check valve in this engine oil system? And if so, its location? The engine plate says it's a 4045HDW52