[cas3]

i had a 47 gmc that had never seen much maintainence so we did the old timer thing of putting 2 gals of diesel fuel in and run for ten minutes or so, and repeat a couple times. i will say that some glops of crud would come out when it was drained, so i guess we did something, but i never put any real miles on it, and never had the pan off to see what was left. naphtha is powerful stuff, but i dont see anything doing much without some agitation of some sort. you could rig up a pump and squirt in there like a pressure washer, but still you have no idea really what you have done. most likely the pump screen is clogged, and is the motor healthy otherwise? maybe do a new pump too while your in there.