Natty C

The high fill reservoir.



Never could find where specifically that the tank was leaking, so basically just threw a part at it on a hunch after everything else in the coolant system checked out good. It turned out to be the source of the coolant loss.

altownsend

Acknowledged everyone. I checked the hoses to the reservoir, and they are seemingly good. I also cleaned the fill tank (the black one that the radiator cap screws into. I still have the dye in the system. I checked the oil a few times using the special light and UV glasses. So far, no detection of dye anywhere.

I will recheck the reservoir, the fill tank, and the oil again for dye. I did another radiator pressure test. I left it pressurized over night. 20PSI. It was 20PSI the next morning.

altownsend

Update: 1990 C4 Corvette Base Model

I put the dye in the coolant a few weeks ago, and I have been checking for dye in the oil, around hoses, or anywhere where leaks may occur. The last major change in my attempt to find a solution was cleaning the fill tank and installing a new radiator cap. After the cleaning and radiator cap, I have monitored the fluid level to see any changes in the level. So far, no change in the level.

I made a presumption. Either the combination or one or the other has given me a presumptive solution. Either cleaning the filler mouth where the radiator cap screws on, or replacing the radiator cap has made my situation better. I checked again on Sunday, May 5, 2024, and the fluid level is as it was when I completed cleaning the filler container and installing the new radiator cap. I will drive the car this week, and recheck the fluid. If it does not change, I will consider my elusive coolant leak resolved.