This is gonna be long winded, but i need to explain. Truck is new to me, I've had for less than a week. This morning when i started it lifter tick, and skipping. Let it warm up, rev'd her up and skip went away. I went to auto parts store, because i was planning on new plugs, and wires. I wanted to drive a little. So i stopped at Autozone and got some plugs, and also Marvel mystery oil. I added in parking lot, and started my 9 mile drive to a different store for the plug wires.
On the way i could here the lifter noise come and go. I got to store, got parts. Now the good stuff..... It cranked over about 1/2 revolution and stopped. Being WTF! I tried again, still a heavy THUNK. I was able to roll backwards, in reverse to pop start. Nothing-just skidded to a stop! I rolled into a parking spot. Check oil- between marks on dipstick. I try the start several more times-Thunk! I call tow truck.

As it sits, I try again. It starts cranking,and i get it fired up. Its skipping. So i shut it down. Get towed home. I'm thinking the timing belt jumped, and i need to pull the head. Well.... I immediately start the inspection: Oil ok, check coolant in radiator-None visible! So now i figure it siezed, and cool down allowed it to crank. But i still feel I need to check the timing belt. Remove cover= belts ok, Timing marks good. So now I figure I have lost compression in a cylinder. Check spark plugs #4 wet fouled, Check compression #1 120, #2 120, #3 120, #4 150 . So now more confused.

So here is my theory, tell me what you think : Blown headgasket, coolant was so low that temp guage didnt read high. When i shut off truck,#4 filled with coolant- Hydro lock!! After 15 min,it leaked past allowing it to crank over. What do you think? Tomorrow i plan to fill coolant,new spark plug and see how it runs.