. Well, I'm disappointed as hell today because it appears that I will be working on the truck in the cold and snow. I do have a question to pose about the issue before I go out and change the engine today. Is there a chance that something with my idle air unit could leak antifreeze into my engine? I'll go back a day and clearly describe what happened. I drove the truck 15miles to town to get animal feed. It ran fine ( other than the usual lifter clacking,) and I shut it off when I arrived. Running fine!!! Loaded the truck and was ready to go back home. Cranked the engine and it locked up and kicked back twice. It did start on the 3rd attempt. Evidently somehow???? It had become hydro locked. The engine was putting out more steam and white smoke than I've ever seen. My first thought was that a head gasket was blown. I rev up the engine a little and the cloud worsened but cleared up when not idling?? After about a half mile, it ran fine and had no more steam coming out of the exhaust. Idling it steams like an old locomotive but clears up driving down the road. When decelerating it does steam/smoke a little. Has anyone ever seen this scenario before??? I've had plenty of blown head gaskets but this one seems different. Any input from the group is welcome and appreciated. Thanks in advance.

 

I had one where the head gasket was actually Ok, and I had symptoms something like you have. When I finally pulled it apart, the cylinder head had actually been eaten away, there was a very small line from the water passage to the cylinder. It slowly got worse to the point I had to pull it apart. Not many places for water to enter the motor so it's a very strong chance you got a head problem, maybe even a crack.

 

This looks like a great time to use a pressure tester. If you have cooling lines going to the throttle body you can block them off to eliminate that as a possibility and pressure up the radiator/cooling system and see if it holds pressure and for how long.
If you are still losing coolant you will be able to narrow down the problem area by pulling the spark plugs and checking to see which cylinder is filling with coolant.

 

. That was the next step until I decided to just rebuild the engine. I have another great running 5vz from my donor truck so I am putting that in my truck and I will just rebuild the original as I can afford to buy the parts I want. I really want to convert it to the super charged 5VZ. Turbo charging has been a thought that has been rolling around in my head for awhile. Regardless of all the planning and pipe dreams, I'm changing the engine because I have been out of work for the covid scare and need my truck to get back to work. Engine change it is. Lol