Lost coolant and getting fog inside windshield

Any amount of hydrocarbons in the coolant system is a bad thing as it only has one possible source. From the numbers I would say you have a small head gasket leak, it may get worse when the engine gets hot. The interior fogging could be a bad core (could test that yourself if you want proof. just "rent" a cooling system pressure tool and use it to put 15 psi of pressure on the core through the heater hoses. If it leaks down either the core is bad or the connectors are leaking.

I see a couple options depending on how much you want to spend and what shape the rest of the truck is in.
If the truck is in very good shape other than this issue and I owned it I would probably drop a reman engine in it and replace the heater core with a unit sourced from the OEM maker.
Or as it sounds like it's a small leak you could get a jug of Blue Devil - Head Gasket Sealer (original not the pour and go stuff) and follow the directions, especially the flush with clean water before adding it to the system. I have used it a few times to get some extra miles out of a vehicle without tearing it down. Never had it plug a heater core or radiator unlike some of the other types that use metal flakes or walnut shells.

Or buy a new truck, LOL... (well you do have that option, but I will say most of the newer stuff is a bear to work on compared to your 1997).

Thanks Steve,
Was hoping with the indication of the heater core leaking again that was the problem, not the head gasket. Especially since the pressure test didn't show a leak down and the mechanic didn't say he had pulled and checked the spark plugs for coolant deposit. I am going to buy a dye test myself and see if it shows a leak. May get a second opinion on the 6 point machine analysis.
I have a gravel driveway where I park so hadn't noticed leaks on the ground especially with the rain we have been having.
Truck has no dents and cab is good except for the seats and one of the few trucks with a 7ft bed. Was hoping to make it to 500,000 ha ha. I have a 2004 with same engine sitting ready for when this one dies just doesn't have the 7ft bed.
Charles

A coolant pressure test may not show a bad head gasket if it only leaks a small amount. Those tests use 10-15 psi while combustion pressures are much higher and could push through a small leak that the lower pressures cannot. I have also seen "one way leaks" where the gasket had failed and would let combustion pressure out but on the intake stroke with the cooling system pressurized it did not leak. Those can drive you nuts!

I use three methods for head gasket testing, the coolant pressure test, then the liquid test (you can rent the tester at many parts stores, you just buy the test fluid) and 99% of the time I use an electronic combustion gas tester, either my five gas unit or the smaller one that detects only a couple gases, neither one of which should be in the cooling system. I have seen those as "loaner tools" as well. Oh, FYI the loan a tool system in most stores = you buy the tool from the store at full price, when you return it in the same condition, they give you the money back, less the charge for any consumables.

Steve, thanks again.
Local Grand Auto, couple young kids working there said they loaned tools but did not have this one. Will try another place.
One last question related to original problem. I think the new heater core or the hoses are leaking. The mechanic who did it six months says it is the head gasket leak caused it by allowing too much pressure in the system, yet the truck is not over heating. Is he correct ? can that be the reason the heater core is leaking again ?
Charles

High pressure in the system can easily pop open a heater or radiator core. They are designed to handle at most 20 psi. The combustion pressures are in the hundreds of pounds. Sort of like blowing up a balloon a small puff at a time. Eventually the pressure will pop the balloon.

That is one issue with the loaner tools, finding a store with them. Worst case would be to buy one, might be cheaper than burning gas. These are a few item numbers.

Lisle 75500.
Block Tester BT-500 or Block Tester BT-700.

Steve, Thanks for all your time. I know you must love that day job, then to take the time to answer peoples questions I really appreciate it. This truck has been really good to me. The vulcan 3.0 is almost bullet proof. Wonder what Ford will do with new Ranger. Hope they offer a long bed.
Charles

The drive train they will be using is going to be the 2.3 Eco-Tech with a ten speed automatic. From what I have seen so far the bed is not going to be very long as they will not have a short cabin model. Just the super crew and super cab.

If so, They just lost a long time Ford owner. My dad gave me the family 1964 wagon for my first car in 1972. I have owned four Ford Rangers starting in 1984. The Ford F150 is just too big. The grille is so big it looks like its compensating for someone's ego, not practical looks. GM trim quality is not up to Ford's standards, but may have to look there.
Charles