Why Engines Need To Stay Cool

An engine in its simplest form is a heat reservoir and a cold reservoir. Energy naturally flows from hot to cold and the engine converts some of that energy to move your car. The greater the temperature difference between the hot and cold reservoir, the more efficient the engine is.

That description is fine on paper, but real engines use real materials and those materials have temperature limits. Your cooling system carries on a delicate balancing act, keeping the engine hot enough to run efficiently but cool enough not to degrade the fittings, gaskets, oil and other BMW parts. If the cooling system isn't well maintained the engine won't run as well.

The Anatomy Of Your BMW's Cooling System

Three systems of BMW parts make up the bulk of your cooling system: the water pump, the hoses, and the thermostat.

The water pump keeps the coolant moving through the engine. Despite its name it isn't actually pumping just water since water isn't efficient enough to cool today's high performance engines. Instead your engine is cooled by antifreeze. Despite its name, antifreez protects against both freezing and boiling. Pumps are driven by a gear or belt that runs off the revolution of the engine and some have secondary electrical pumps for additional cooling.

The term "hoses" refers to a collection of BMW parts that also includes valves, the radiator, and the expansion tank. This array of fluid paths allows the coolant to come into contact with as much of the engine as possible. The more contact, the more efficiently it cools.

Your engine doesn't have just one thermostat but a number of temperature sensors located throughout the engine. In this context it also refers to valves controlled by the thermostats. These valves control flow of coolant so that it is circulated only as the engine needs it. Ideally the engine should heat up quickly and then use coolant to maintain optimal operating temperature.

Maintaining The Cooling System

There are a few steps for owners to take to ensure the BMW parts responsible for keeping the engine cool run in top condition.

Routine maintenance includes replacing the coolant at specified intervals. Because the coolant is exposed to such great heat it breaks down over time. It also picks up impurities from the engine. For this reason, the coolant should be replaced as specified in the maintenance manual.

Hoses should be checked every six months for cracks or leaks and if any are found they should be repaired or replaced immediately. In the absence of visible damage, all hoses should be replaced every few years.