Ford f350 diesel Engine will not start cold, smoke leaks from the engine, fuel gage

Three Problems:
1. Engine will not start cold
2. Smokes leak out from top of the engine near the spark plug/glow plug (front of the engine)
4. Front gas tank gas indicator only shows empty, even if it is full.

I recently bought a 83 Ford F350 Diesel Truck (dually)
It was hard to cold start, and I have to use lighter fluid to get it started. Once it start for 10 minutes or so it would start again without any problem.
What could be the problem? Is it glow plugs. It has a block heater to plug in to a 120V electric outlet and I did plug few times over night, but it did not good.

Second problem:
Once the engine runs about 15 to 20 minutes, some white smokes come out of the top of the engine where the sparks plugs and glow plug on the first one (front).
Then after the oil really warms up in the engine, then the smokes come out from the dip stick. The radiator water also has little oil in it. But water level stays the same. Of course I have replace oil every 100 to 200 miles. Also the smoke coming out from the tail pipe is grayis white and it also smells like oil.

Third problem:
It has 2 gas tanks, front and back. On the dash board it has a selector switch to select one tank at a time. I filled up Both tanks , but only the back tank indicate the gas level. When I switched to the front tank, it shows empty.

I greatly appreciate your input and your stories on such a problems like mine.