fuel in oil pan?

i was wondering if you could help me out...this is my first time on this forum...i have a 1989 GMC 2500 4x4 pick up with a 305...and my problem is that we are finding fuel in the oil pan...and we can't seem to figure out why this is happening...does anyone here have any ideas on what we should look for to figure this out...any suggestions you have would be greatly appreciated...i need help with this as soon as possbile as this is our plow truck and with winter on it's way we'd like to get this figured out soon

Thanks a bunch
Jen

Is this EFI or a carb.

If its a carb, is there a fuel pump on the engine block? Thses things can leak internally straight into the crankcase.

If its EFI, you should have a throttle body EFI, where the only way fuel can get in the block is with a combination of leaky piston rings, a misfire and/or an excessively rich mixture (as caused by a bad O2 sensor or similar problem.

MagicRat has it right on the money. But it could also be caused by a faulty PCV valve. (Positive Crankcase Ventilation). The PCV valve is supposed to take all blow by gasses that gets past your rings and gets into the crankase, back into your intake to be reburned. If the valve is plugged, it will not be able to do this, and may cause fuel unburned gasses to be in your crankcase (oil pan).