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My car behaves about the same way. I suspect the radiator is partly clogged. The engine runs well and the coolant never boils. Of course, the hotter the weather and the hotter the engine, the more likely vapor lock becomes. It seems that cooling on the 110 and 120 Packards through 1937 was marginal at low speeds. I think this is due to restricted underhood air flow. As far as I know, no fan shroud was ever used, and the narrow radiator core and other considerations limits fan size and pitch. The 1938 models had redesigned inner fender panels that probably went a long way toward better cooling. The '38s had a better water pump and pressure cap, too. In cool weather, up to about 80F, my cooling system does a good job. As temperatures climb above 90F, the engine runs hotter, but does not boil over or lose coolant. The gauge will read 175 to 180 in cool weather, and will climb to 190 to 200 in hotter weather when driving at 50 MPH or so.
It gets very hot around here in summer.

When you shut down a Packard, the engine will absorb heat from the hot exhaust manifold. This is normal.
With modern gasoline, this can cause carburetor flooding and may contribute to vapor lock. Park facing the wind, if you can.

Thx Tx. So it sounds like it is normal.

I just saw something that I have not seen or at least recognized before. What’s this tube for coming out of the radiator? Is it for air flow? It just goes down to the bottom but to nothing so I assume it is to get air to help circulation?

It then had me questioning how much coolant I should be putting in as the tube is on the bottom of the overflow tank. I do see some coolant on the frame below where the tube ends. Not sure if that is one of the sources of my “leak”?

That tube is the overflow tube. If coolant level gets too high it drains out that tube and onto the ground. If your cooling system is unpressurized (I'm pretty sure it's unpressurized) then the tube sticks up a certain amount in the upper tank. Any coolant above that level goes in the tube and out to the road. My dad's '38 Super is this way, except the overflow tube is located under where the cap is.

ok. Thanks. That makes sense. It must be raised up a bit in the tank, as when i fill it, it does not come out, nut it looks like it does when I am driving, or when it gets hot.

Sounds fairly normal based as when idling you are getting the least amount of airflow through the radiator and fan isn't turning as fast.

At one point Packard offered an optional fan for the 110 and 120. (Service bulletins or shop manual) They warned that the optional fan would be noisier than the standard fan and would pull more power. I think the '36 and '37 cars had an improved fan as standard equipment. One problem with a higher capacity fan is that it will require more power at highway speeds, and that will require a tighter fan belt, which the water pump bushings will not like. My car has an electric fan attached in front of the radiator and operated with a manual switch. It helps cooling at low speeds, but it draws a lot of amps. I suspect it may actually block airflow somewhat at higher road speeds. It would be an advantage in heavy traffic or in a parade in hot weather, but the substantial current draw taxes the stock generator. A good clutch fan would be nice, but there isn't room for such a thing. The '36 & '37 hood louvers look very restrictive to me, and the engine compartment is not nearly as well ventilated as most. The inner fender panels on my car are too nice to cut up, but I'd think a custom pair of fender panels made much like the 1938 ones would substantially improve cooling. The '36 & '37 inner fender panels lack any concession to ventilation.

Thx guys. Will just need to keep an eye on the temp gauge.

Back to the ammeter. I took her out last night, and noticed that when I turned on the lights, the ammeter ticks up on the positive side now. Not much, probably 5-10.

Again, is this normal when lights are on?

Any electrical load should pull the ammeter toward the negative direction. The ammeter could still show positive if you are driving and the battery is charging, but it will be less positive with lights/electrical load. With the car not running the ammeter should definitely show negative if you turn the lights on.

Thanks Don. So previously, it was showing negative at start-up, idle and driving. I reversed the wires on the ammeter, and that corrected that, where it was now reading 0 at start idle and driving. Now it is positive when lights are on. This occurs when the car is turned on or off.

What is the suggestion? Reverse the wires again?

It sounds like you probably had it wired correctly before. It should definitely read negative with lights on and the car off. With the car on at normal idle and lights on it may still read negative. But, when you increase the idle it should go positive when charging.