Whether you go to a professional car wash or just break out the hose and wash cloth every now and then, most drivers will dedicate some time each year to cleaning their vehicle. A rainwater rinse just doesn't cut it, and a thorough cleaning can make a vehicle look much more appealing.

But even if you're fairly fastidious about vacuuming your seats and scrubbing down your windows, you might overlook the engine bay. A lot of dirt and grime will build up in this part of the car, and it won't get cleaned off during a traditional wash.

Drivers may consider that a greasy engine is necessary for an engine to run well, or worry that cleaning will cause damage to essential components. But carefully cleaning an engine can be beneficial in a number of ways. Not only does it look nicer, but it can run more smoothly than a dirty engine, avoid complications with components such as wiring and sensors, and make it easier to find leaks or other problems.

Don't work on the engine until it has cooled down. A hot engine can easily cause serious burns, and the temperature differential can cause metal to crack when you spray water on it. An engine which is still slightly warm can be helpful, though. The fuel treatment company Bell Performance says warming up the engine for five to 10 minutes can soften up any gunk and make it easier to remove.

Remove any larger pieces of debris that have made their way under the hood, such as leaves or twigs. The automotive site Autoblog says compressed air is useful for dislodging any hard to reach items. Avoid using water for this purpose, this it can cause debris to clump together into a sodden mess.

You'll also want to use plastic to cover up any sensitive electrical components before you start spraying water or using liquid cleaners. Use plastic bags or aluminum foil to cover up the alternator, air filter intakes, sensors, and any other areas water should not enter.

Cleaning the engine is also a good time to take care of any corrosion on the battery. Paul Wright, writing for Popular Mechanics, says you should disconnect the negative cable before the positive one to avoid a short circuit. Brush the battery terminals, using a baking soda and water paste if they are particularly corroded. You can also soak the cable ends in a corrosion neutralizer.

Water-based degreaser can be liberally applied to the engine components. Bell Performance says you should be ready to rinse off the degreaser if it gets onto any exterior surfaces, since it can strip the wax.

Allow the degreaser to work for a few minutes, and then start scrubbing the surfaces. Autoblog recommends having brushes of different sizes, including a wheel brush, paint brush, and toothbrush. Toothpicks work well to clean out tighter spots.

Once you have dislodged the grease and grime, use the spray from a garden hose to wash it away. Pressure washers can also be used, but should not be set on high since this can damage certain components. Pat Goss, writing for the automotive site MotorWeek, says you should never use a steam cleaner since the moisture from this device can get into the electrical components. Elite Auto Repair, a business in Tempe, Ariz., says you should use a sweeping motion when hosing down the engine and avoid keeping the spray in one area for too long.

Allow some time for this water to evaporate. Compressed air can help speed up the process, and you can also dry slightly damp surfaces with a microfiber cloth. Starting the engine and letting it run for a few minutes will let you know if there are any problems and will also help more water evaporate.

Once the engine is relatively dry, remove the coverings from the electrical components. While these areas are sensitive to water, they can still be cleaned with a damp cloth as long as it is not too moist.

It can be easier to spot leaks in a clean engine, so you might want to take this opportunity to do so. Wright says one method is to use ultraviolet dyes to add to your oil and coolant. After a drive, you can use a UV filter on a flashlight to see if any fluid has leaked out.