Helping a friend with a 48 216 engine that he had rebuilt by a reputable machine shop 6 years ago and was only run then on a dyno. I'm putting the truck back together for him and started the engine up and after about 10 minutes the oil pressure started to go down to almost zero. I shut it down and drained the oil to find a lot of anti-freeze in the oil. I did fill the radiator the day before and ran the oil pump with a drill to get things lubed. Checked the oil dipstick before starting it and was normal. Can't figure out how the anti-freeze is getting to the crankcase. I pulled the oil pan off, filled the radiator back up with water and applied 5 psi to it and it's not losing pressure and no leakage in to the crankcase. Very confused. Any ideas. Thanks Dave
