Downsizing the automobile over the past several year has helped change America's cars from gas guzzlers to gas sippers. The result of this redesign is smaller, lighter cars. Most of them are front wheel drive, powered by a transversely mounted four-cylinder or V-6 engine.

Even though the cars and engines are smaller, the way people drive may not changed. Most cars are still subjected to prolonged high-speed driving, frequent stops and starts, occasional heavy overloading and inadequate or improper preventive maintenance.The end result is that the smaller engine runs approximately 25 percent faster and creates 15-20 percent more heat that the large V-8 engine that was the standard 10 years ago.

Specifically, belts, hoses and other engine components are subjected to a variety of heat sources. These include the temperature of the coolant and radiant heat sources, collected together in a smaller engine compartment, which generate higher underhood temperatures in today's downsized cars.

These under-hood temperatures, according to The Gates Rubber Co., can contribute to premature hose and belt failure. Hoses and belts may become cracked or brittle due to excessive heat. All rubber parts should be checked for these signs of wear any time the hood is opened.

In addition, in downsized cars radiators are smaller, and accessory drives such as the water pump, work harder and at higher speeds. Therefore, especially in smaller cars, maintaining an efficient cooling system is very important.

Also, four-cylinder car engines tend to vibrate more than larger engines. This can lead to loose fittings and attachments that can reduce the life of under-hood components.

Manufacturing technology has been improved to meet the greater heat and wear demands created by downsizing cars. For example, improved braids and reinforcements on belts and hoses and other higher heat-resistant compounds are used in the manufacture of these parts.

However, despite these improved standards, emphasis needs to be placed on preventive maintenance.