Coolant level problem

[1996B4000]

1996 B4000; 5-speed stick; 196,000 miles.

About six months ago I found a pinhole leak in the radiator. Local shop changed the radiator.

I check fluids and tire pressure weekly. EVERY time I check to coolant level, the reservoir is empty and the coolant in the radiator is barely visible. I just keep adding fluid to both.

The truck is parked in a garage with cement floor; no evidence of leaks -- no oil, coolant, or fluid of any kind on the floor. Temp gauge stays slightly below mid-point.

What is going on? What can I do about it?

Thanks,
Your average old guy

 

[Mbrooks420]

Most likely out the exhaust pipe. How many miles driven between empty reservoirs?

 

[RangerX]

I had the same mystery with my 94 B4000, disappearing fluid with no visible leak. I was having to add about a half gallon every couple days.
Last month I tried K Seal in the radiator and have not had to add fluid since!