Disappearing Engine Coolant

[Jim_HiTek]

Water pump often the source of mystery leaks. Flings the coolant around so it never makes it to the ground. After heating up. When cool, no leaking.

Also, heater core hoses...look for telltale streaks

[MrMark52]

Looked this morning after engine idled for awhile yesterday - coolant level in recovery tank returned to where I filled it to yesterday.

Not a conclusive indication, but a step.

[MrMark52]

Another 2 idles in the driveway - fluid returns back to the original level in the coolant tank.

May try to do a 50 or so mile run over the next few days.

[MrMark52]

Well - I think the mystery is solved - after several engine idles in the driveway, coolant level in the reservoir continues to return to the same place.

Interesting - during the recent cold snap here in Texas, the level went down as the engine soaked in the frigid environment, probably 1/2” in the reservoir.
And as the temperature has warmed (it was 70 yesterday), the fluid level has returned to its normal fill point.

Thanks to all for your input! It appears the issue was caused by my not “burping” the heater core (see my previous post in this thread).