What's Under the Hood

Obviously, to look under the engine hood you first have to raise it, which is sometimes not so simple a task as it sounds. The engine is in the front on most American and foreign cars. First look under the dashboard to the left of the steering column for a hood release device; that is where they are positioned on most cars, but they come in a variety of shapes and are sometimes located at the front of the hood.

The next place to try is at the front of the car; reach your fingers through an opening in the grill and feel around for a release lever. The Owner’s Manual contains both the location and instructions (it may be indexed us “bonnet” in foreign car manuals), but if you have a problem with it, stop at a service station or ask the dealer where you purchased the car for help. Once you have located the release and raised the hood, do it several times until you memorize how it is done.

There are three kinds of hoods, varying in their location and the way they open. The most common hood is located at the front end of the car, is hinged near the windshield, opens at the front, and has two catches. After the first catch is released, the hood raises perhaps an inch, and the second catch must be activated to raise the hood completely. (That second catch is there as a safety measure to prevent a hood from being accidentally released and blown back while the car is in motion.)

Another kind of hood located at the front end of the car has the hinges at the front with the opening near the windshield. This type of hood has only one release. The third kind of hood is located at the rear of the car and is called a “motor lid” on a VW Beetle or bus and some other cars. With some foreign cars that have rear engines, for instance the VW  Beetle, the trunk (or “boot”) is in the front of the car and the catch release is in the glove compartment.

A raised hood, incidentally, is the universal distress signal, so if you break down on the road raise the hood and tie a handkerchief to the radio antenna. While you are trying to figure out the trouble, perhaps some kind soul will stop or will send help.

When you first look under the hood the vast array of wires, hoses, and unfamiliar items will almost overwhelm you. Take heart, you are not supposed to know what each and every part is and how it performs or how to fix it. 

You are going to learn simple repair, proper car care and maintenance, and preventive maintenance; as you learn the function of a few parts and how to care for them, the engine will not look mystifying any more. 

The more you learn about the engine the more you will appreciate the marvelous arrangement of coordinated devices that perform at your command and operate precisely with all parts synchronized to do the best job.

Here is a simple explanation of how a four-cycle gasoline engine - the kind found in most American and foreign cars works. The source of the horsepower in a car is a series of four to eight pistons, which are located in the engine and housed in cylinders. Each piston moves up and down in its cylinder, and by means of a connecting rod this movement causes the crankshaft to rotate; this movement, in turn, is transferred to the wheels themselves.

The source of energy for the pistons is a combustible mixture of air and gasoline which is fed by the carburetor to the cylinder that houses the piston and ignited there by a spark from the spark plug. The carburetor mixes air and gas in correct proportions to form a vapor that will burn rapidly.

In a four-cycle engine, it takes four strokes of a piston, two up and two down, to complete a full series. Then the procedure starts all over again.

Stroke 1. The piston moves down, drawing the fuel-air mixture into the cylinder from the carburetor.

Stroke 2. The piston goes up, compressing the mixture.

Stroke 3. A spark ignites the mixture, which burns rapidly, forcing the piston down.

Stroke 4. The piston moves up, expelling the burned gases.

In addition to compression, three vital elements are necessary to make the engine run: fuel, air, and electricity. If the engine turns over hut will not start, or coughs to a stop while you are driving, the most likely problem is that you are out of gasoline. Even if you filled the lank yesterday, that does not always mean you have plenty today; maybe a thief stole your gas during the night.

The second item—air—is always present, and you will never have (don't worry about running out of it. A properly balanced mixture of air anil gas is led by the carburetor to the engine. Though an incorrect mixture will increase fuel consumption, it probably will not prevent the car from starting.

That leaves electricity, and now we have to do a little trouble-shooting. When the starter will not turn the engine over, the lights will not burn, and the horn will not blow, then there is no electricity following from the battery to the starter. Either the battery is dead (out of juice) or the terminals are corroded. If there is some white or grayish pillings on the terminals, loosen the cables with a wrench or pliers, remove them, and clean off the terminals. Then replace and tighten the rubles; that may correct the problem.

If not, you will probably need jumper cables and a helper battery to get going. If your battery has life and spins the engine but it can not start it running, then you have more serious problems in the electrical system, such as points, condenser, plugs, plug wires, or distributor—trouble that may be beyond your ability to correct.

UNDER THE HOOD

As you look under the hood, you can identify the belts on the pulleys- These drive the fan and alternator (generator on some foreign cars). Hells also drive some of the optional equipment, such as an air conditioner compressor and power steering pump.

You will also sec an array of insulated wires coming from a round device called the distributor. The distributor sends electricity over the various wires to the spark plugs in the proper sequence. The wires spread from the distributor to each of the spark plugs in octopus fashion. Each cylinder has one spark plug; if you drive a four-cylinder car, then you have four spark plugs. A V-8 of any make has eight spark plugs, four on each side of the engine. An electric spark jumps across the electrodes of the spark plug and ignites the fuel-air mixture.

The air cleaner is usually a large, round, canlike item, most often located above the carburetor right over the engine. Inside the air cleaner is a paper filter that removes dust, dirt, and other objectionable particles from the air entering the carburetor. This paper filter must be replaced when it gets dirty; refer to your Owner’s 

Manual for suggestions on how often to check or replace the air filter. The carburetor mixes the gas and air in the proper proportions to form a vapor that will burn in the engine.

A plastic container holds water or water and chemicals to clean the windshield. Detergent or a special cleaning solution can be added to the water to do a better cleaning job. In winter, use a special solution containing antifreeze, or add a deicer to the water in the container to prevent freezing.

The alternator is a round device approximately 6 inches in diameter and 6 inches thick. It has a pulley that is belt-driven and it produces electricity to keep the battery charged. About fifteen years ago some American car manufacturers started using alternators instead of generators. 

Older VW’s have a generator, but recently foreign car manufacturers switched to alternators and now practically all American and foreign cars have alternators.

The alternator is more efficient than the generator and has a higher capacity than a generator of equal size. When the dashboard alternator warning light (GEN) comes on, the most likely problem is that the drive belt has broken. Pull over to the side of the road and let the engine idle while you open the hood. If the drive belt is broken and the fan is turning, close the hood and drive to the nearest service station or garage for repairs.

Do not turn the engine off! Your battery may be run down and may not start the car again. While driving for help, turn off the radio, air conditioner, heater, and other electrical equipment to conserve electricity, because the alternator is not replacing the electricity used. If the drive belt is broken and the fan is not turning, turn the engine off at once! (On some cars the fan is driven by the same belt that drives the alternator.) 

You will have to obtain help. With the fan stopped an engine will soon overheat, and expensive damage to the engine may result.

Next find the radiator, the large metal container located between the engine and the grill which contains the antifreeze or mixture of antifreeze and water that is used in the cooling process. 

You will see two rubber hoses attached to the radiator, one at the top and one at the bottom. When these hoses get soft or easy to squeeze, they should be replaced, normally about every two years (see Chapter 18, Tips on Medium Tasks). 

Cars with air-cooled engines do not have radiators; an example is a VW with the engine in the rear.

The proper liquid level in the radiator is extremely important. Your car has either a sealed cooling system or a conventional pressure cooling system. 

A sealed cooling system has a translucent plastic container, which holds the overflow coolant; this is located near the radiator and is connected to it by a hose entering the radiator near the cap.

The battery is easy to identify; it resembles a cube in shape, being about 10 inches long, 7 inches wide, and 8 inches deep. The battery is called the storage battery because it provides electricity to start the engine and then is recharged when the engine is running. 

Two heavy insulated electrical cables attach to terminals on the top or on the side of the battery. On the top are six vent caps or lids (except in some new butteries, which never need to have water added). Each vent cap must be removed to check the liquid level in the battery.

Ask the seller to show you where the battery is located if you buy a foreign car, or you may have to hunt for it. For example, some Fiats with rear engines may have the battery under the floor mat of the front trunk. A VW Beetle has the battery under the rear seat; lift up the lower part of the rear seat and you will locate the battery on the passenger side. Most foreign cars have the battery located under the front hood, just as in most American cars.

The oil dipstick is used to check the engine oil level and is located on the side of the engine. You can identify it by the loop at the stick, which allows it to be pulled out easily for checking.

If your car has a manual shift, there is only one dipstick under the hood. If you have automatic transmission, there is a transmission fluid dipstick to measure the level of the transmission fluid. 

This dipstick is located at the rear of the engine near the fire wall. This partition is fire-resistant to lessen the danger of fire getting into I lie passenger compartment from the engine.

You do not normally have to worry about checking the transmission fluid, which is checked when the car is serviced at regular intervals. 

If for some reason the transmission fluid becomes low, the automatic transmission will be sluggish in shifting. You can have the transmission until checked at the nearest garage or service station, or check it yourself  and add some fluid if needed.

The items I have named are certainly not all the things found under the hood. But they are the components that are easily seen or located, but the ones you will be concerned with in performing basic auto cure. 

After you can identify these parts, you should check the hood us often as necessary to protect the engine and give you peace of mind, perhaps every two weeks or every 500 miles. 

This check should include I he liquid level in the radiator, the liquid level of the battery, nnil I lie level of oil in the engine. In addition, the tire pressure should be checked.