Cold weather driving Options

[Grosbard]

I haven't driven my car in cold weather yet, and I have a couple of questions for you more experienced guys.

So far I've only driven the car on warm, or moderate days (70 degrees and up). It is having an overheating issue. i.e. engine temp gets too high after 60-90 minutes of highway cruising on a hot day, so I have to pull over and let the car cool down. Then I'm fine again for another 60-90 minutes.

The overheating issue needs to be fixed, and it will be taken care of this winter. In the meanwhile, I might take a drive in the near future. The current weather here in the northeast is around 40-50 degrees fahrenheit.

So my questions are:

1. Would the outside air temperature being 40 or 50 degrees significantly change my overheating issue to the point where it won't be a problem, or in the grand scheme of things is the engine so much hotter than 20-30 degree difference in ambient temperature, so it won't make much difference.

2. I don't have a heater in the car (another thing that will be resolved this winter). Do you guys think it would be too cold in the car for a drive with my wife on a 40 degree day (or a 20 degree day), or would the heat radiating from the engine compartment keep the cabin pretty comfy once the car has warmed up a bit?

Thanks for all your help!

[era vulgaris]

. i.e. engine temp gets too high after 60-90 minutes of highway cruising on a hot day, so I have to pull over and let the car cool down. Then I'm fine again for another 60-90 minutes.

If the overheating only happens during highway cruising on a hot day, a few things come to mind.
What engine speed are you cruising at? What gear are you in? Is the top on or off?

If the top is off, you're drastically increasing your air resistance. At highway speeds (55mph and up) the engine already has significantly more load than at non-highway speeds due to air resistance. With the top off, that load intensifies even more (I had a digital CHT gauge in my old car, and I can't recall the exact number, but there was around 10 or 15 degrees difference in head temps at 70mph with the top off vs on). And then if you couple that with low rpm cruising in 5th gear, your engine temps will creep up like you describe. I generally don't like using 5th gear below ~3500rpm for more than a couple minutes unless I'm on a flat-to-downward grade and the top is on, and definitely never cruise in 5th gear below 3000rpm regardless of conditions.