Bought a GMC 55 first series P/U with a 248 ci engine. Previous owner ( also a good honest friend) said motor was rebuilt 200 miles ago by local reputable shop. It sat in his drive way for 3 years with antifreeze in it.
I dry started it last week, 30 seconds,to insure all was ok before putting freshly painted fenders on. It started easy and sounded great. I drained the oil for an oil change, and noticed green antifreeze was 1/4 of the drain pan contents with milky grayish oil floating on top.
Where do I start looking , testing, and doing?
