Speedo glass condensation

[Frango100]

After driving a few kmīs, the speedo glass gets condensation on the inside. After driving for a longer time, the condensation disappears again. The whole instrument panel becomes quite warm, almost hot. I didnīt find any air coming in from the engine bay area, so what could be causing both issues?

[Yadkin]

It must be quite humid in São Paulo. These instruments are not tightly sealed and therefore receive the same atmosphere as the outside. As the interior portions of the instruments heat up moisture is driven off and collects on the exterior portions that are cooler. Eventually the whole thing heats up and the condensation returns to invisible vapor.

We have high humidity here in North Carolina during the summer. What I do to manage it while parked in my unconditioned garage is to set a jar of Damp Rid in both the closed cabin and closed trunk.

[Frango100]

We are now in the middle of the raining season and the humidity is around the 70%, but when I'm not wrong the condensation also occurred in the dry season.
I also keep two jars of that anti moisture stuff in my bird, also one in the cabin and one in the trunk. The first ones where full in a bit more then a month, the new ones are in there for a week and are still dry.
Is it normal though that the whole instrument panel heats up?

[Yadkin]

There's a big motor behind that firewall and it will heat up everything around it. Same for the "hump", due to exhaust. When I rebuilt my car I put a lot of insulating material in these areas and it helped immensely.

Also the HVAC systems in these old cars don't dehumidify as effectively as in modern cars. Modern cars use a combination of the AC circuit and the heat circuit to dehumidify. Before I modified mine with a Vintage Air Gen IV system I had to have a towel handy to defrost the windshield.

[tmjsong1aolcom]

You are correct the instrument panel should not heat up. As for the condensation, this does not make sense,

Is there insulation on the inside of the firewall under the dash?

I cannot speak to others birds but neither of my 58's exhibit your problems.

Is it possible that the heater core has sprung a leak??

Good Luck
Fuz
58's&64's
tmjsong1@aol.com
Sun Prairie, Wi.

[Frango100]

Hi Fuz, the heater core on my bird is not connected, it was probably leaking before.
I wonder if there could be any moisture in the speedo cable, which would evaporate due to the heat. I never drive in the rain though and also donīt use a garden hose to wash the bird.