One advantage of the modern automobile is this: Its owner need not worry about summer driving with the air conditioner on, even in bumper-to-bumper traffic. Today's cars are tested to extremes of both cold and heat, meaning the likelihood of the temperature gauge ever reaching critical mass isn't very great. For those with classic cars and muscle cars, summer driving can occasionally be an exercise in paranoia, particularly if a smooth flow in traffic suddenly devolves into a sea of red brake lights.

There are many products on the market today that will lower engine temperatures (thus boosting performance) when the outside temperatures climb towards triple-digits. First and foremost, it's critical to start with a healthy cooling system, as a new radiator will have little benefit if the engine block itself is saddled with clogged coolant passages. Assuming that the cooling system presents itself in good overall health, a radiator upgrade is one of the better ways to reduce underhood temperatures.

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