I think I screwed up. I changed oil in the '59 two weeks ago and it was black already from running the truck tuning it up, etc.
I drained the oil yesterday. Then I refilled with oil and added a quart of fuel oil and ran truck for about 20 minutes. I then drained it again and poured 2 quarts of fuel oil through it to flush the motor out. I refilled with new oil and installed new filter.
The truck always had great oil pressure but now the truck has great oil pressure at startup and then pressure starts to rise and fall like the pump is not picking up oil. If I shut it off, let it sit and restart there is great pressure again then rising, falling pressure.
My guess is there is sludge in the pan that didn't flush out and it is clogging the oil pump inlet after running a minute or so and then drops away when shut down, repeating each time the truck is started. ...OR.. the pump is pumping the pan dry and oil returns are partly plugged so oil takes too much time returning to the pan and pump starts cavitating.
Any ideas????
QUESTION...can the oilpan be dropped from the motor as it sits in the truck or do I have to unbolt and raise the motor. Truck is a '59 1/2 ton, motor is a 235.
thanks in advance...
Carl
