This happened to my 240 once, I checked the dipstick and it showed no oil. Put 2 more quarts in, still no oil on the dipstick, put another quart in, nothing. Figured something was wrong so pulled the plug on the pan and dumped almost 7 quarts of oil out with a strong smell of gas. Turns out the fuel pump diaphram had ruptured and was leaking gas into the oil pan, daluted the oil = no oil pressure. I talked to a mechanic about it and he said I was lucky I didn't blow the oil pan off. Change the oil anyway and see if it doesn't improve the pressure.
Steve
