Under the Hood - Inline 4 Cylinder 1

In my Under the Hood series, I plan to photographically document the engine compartments from as many different vehicle types as possible.* I will then label the most common maintenance items and briefly explain the purpose of each component and system. My overall goal is to help those who do not know their way around an automobile's engine bay and may be intimidated by it.

* Engine bays are different between models of cars, however, most cars in the same class are similar enough that if you know your way around one you will be able to find your way around another.

This episode features a "new" car one of my brothers recently acquired. It is a 1999 Nissan Altima with the 2.4 Liter 4 cylinder engine. Click on each photo for a higher resolution view.

1. Engine Oil Cap
   
2. Engine Oil Dipstick (hidden from view in photograph)
   
3. Radiator
   
4. Radiator Cap
5. Upper Radiator Hose
6. Engine Coolant Reservoir
7. Windshield Washer Reservoir
8. Fuse/Relay Boxes
9. Battery
10. Air Filter Housing
11. Mass Air Flow Sensor (MAF) location
12. Brake Fluid Reservoir
13. Power Steering Reservoir
14. Spark Plugs
15. Distributor Cap

1. Engine Oil Cap
2. Engine Oil Dipstick
3. Radiator
4. Upper Radiator Hose
5. Engine Coolant Reservoir
6. Windshield Washer Reservoir
7. Fuse/Relay Box
8. Power Steering Fluid
9. Spark Plugs
10. Alternator
11. Accessory Drive Belt

1. Spark Plugs
2. Distributor Cap
3. Lower Radiator Hose (barely visible in photo)
4. Battery
5. Air Filter Housing
6. Mass Air Flow (MAF) Sensor location
7. Brake Fluid Reservoir
8. Brake Booster
9. Fuel Filter
10. Fuse/Relay Box

In these three photos, you can see the basic maintenance items common to most cars. I will write a brief description of each component outlined in this episode and, if applicable, any quick and easy maintenance checks you can perform on the component.

Engine Oil Cap - Add oil here

Engine Oil Dipstick - Use to periodically check the oil level in your engine. To check, remove the dipstick, clean it with a rag, and fully reinsert it. Remove the dipstick again and note the level of oil. If the oil is in the cross hatched area it is ok. If it is below, slowly add oil through the Engine Oil Cap until the oil level is within the cross hatched area.

Radiator - The radiator works to keep the engine from overheating. You can visually check the bottom for leaking coolant.

Radiator Cap - If the car has been used recently be very careful removing the radiator cap because the system will still be pressurized and hot steam could scald you. When in doubt, listen for a hissing sound when you turn the cap. If you hear a hissing sound, do not remove the cap. Otherwise, remove the cap and look at the coolant inside the radiator. If it is discolored (there are lots of different colors of coolant, so you will have to know the original color in order to know if the coolant's color is different) you may need to flush the cooling system. Also, make sure the radiator is full of coolant.

Upper and Lower Radiator Hoses - Visually check the hose for any cracks, holes, deterioration or any other signs of leakage.

Engine Coolant Reservoir - Check the level of coolant and make sure it is not above the "COLD MAX" line on the exterior of the reservoir.

Windshield Washer Reservoir - Open the cap and look inside. If you can't see any fluid, add fluid.

Fuse/Relay Boxes - To check a fuse, remove it and look through its side. If the wire connects the two prongs, it is good. If the wire is broken, the fuse is bad and should be replaced with a fuse with the same number.

Battery - Most auto parts stores can test your battery for free. Make sure the battery posts and wire terminals are clean and do not have any built-up corrosion. Corrosion will look like white, clumpy powder. To clean the posts and terminals, remove the negative terminal first, then the positive. You can use a wire brush, scrub pad, commercial battery post cleaner, or a 3:1 baking soda/water paste to scrub the battery posts and wire terminals clean. If you used any method that involved liquid or paste cleaners, allow everything to thoroughly dry before reinstalling the terminals onto the posts. Always reinstall the positive wire first, then the negative. You can smear a little petroleum jelly over the posts to help prevent future corrosion. (Note: after uninstalling the battery, the car may run slightly more rough than before because the car's computer's memory will have been reset and it will take a few miles for it to relearn its previous settings).

Air Filter Housing - The air filter is located in here. To access the air filter you will have to remove some clamps or screws (depending on the car). Pull the air filter out and visually inspect it.

Mass Air Flow Sensor (MAF) location - Inside the air intake tube (after the air filter) is the MAF. There is no regular check you can do, but if you ever need to clean the MAF due to a rough running engine, you can spray electronic cleaner spray over the wire.

Brake Fluid Reservoir - Visually check to make sure the fluid is at the proper level.

Power Steering Reservoir - Visually check to make sure the fluid is at the proper level. Some systems use a dipstick method of checking the fluid level.

Spark Plugs - Spark plugs do not need to be checked very often, usually about 30,000 - 60,000 miles.

Distributor Cap - Visually inspect for any cracks.

Alternator - Most auto parts stores can check your alternator for free. The alternator basically converts power generated by the engine to charge the battery and run the accessories, like lights and radio. When the engine is not running, the lights and radio run off the battery.

Accessory Belt - Some vehicles will have one serpentine belt, some have two belts - one that drives the Air Conditioning Compressor and one that drives the Alternator, Water Pump, and Power Steering. Visually check the belts for frays, cracks or missing chunks.

Fuel Filter - Fuel Filters can be located under the car near the gas tank, in the frame rail, or in the engine bay (like this 1999 Altima).