KISS; I'm not talking about the radio itself...the poster asked where he should locate the circuit he is building. If he locates said circuit in the engine compartment, temperatures may reach above 100C. The inside cabin has much lower upper temperature extremes.
Now, to the lower extremes, the poster has indicated he lives in Canada. Depending exactly where in Canada, it can get pretty darn cold. Perhaps not -40C, but -20 to -30C may be fairly common. At least the passenger cabin will be warmer.
Lastly, water, fluids, grime....they will still be present in the cabin but at reduced rates.
That is the reason electronic modules inside the cabin can get away with a conformal coat, but modules outside the cabin have to be completely potted.
Now, to the lower extremes, the poster has indicated he lives in Canada. Depending exactly where in Canada, it can get pretty darn cold. Perhaps not -40C, but -20 to -30C may be fairly common. At least the passenger cabin will be warmer.
Lastly, water, fluids, grime....they will still be present in the cabin but at reduced rates.
That is the reason electronic modules inside the cabin can get away with a conformal coat, but modules outside the cabin have to be completely potted.