Safety Rules for Automobile Self-help
Expect to get grease on your hands and expect to break a fingernail. Use common sense when making inspections and repairs. Here are some common sense rules to follow while working on a car:

Gasoline fumes and hydrogen gas are both explosive, and both gasoline and oil are flammable. NEVER smoke while making repairs or even when opening the hood to diagnose the problem.

Always keep a small fire extinguisher nearby while working on the car, particularly if working under the hood.

Engine exhaust fumes contains poisonous carbon monoxide. Never run the engine in a closed area without ample ventilation. If you begin to feel sleepy while working on a car, quickly move away from the vehicle into the fresh air. Likewise, if you can smell exhaust in the car while driving, open the windows at once.

Car batteries contain sulfuric acid, which burns skin, and it emits hydrogen gas, which may explode. Wear gloves while working around a battery to protect your hands, and do not smoke near it.

Car batteries can give electrical shocks and are a fire hazard. Disconnect the battery while working on the fuel line or electrical system. It is only necessary to remove the ground cable from the black (-) terminal on the battery casing.

Prevent electrical sparks or jolts when jump-starting a car, which can create a fire hazard. Always match cables and terminals. Connect the positive (+) terminal of the helping car to the positive terminal of the disabled car, and the negative (-) terminal to the engine frame before turning on either engine. Never touch the positive cable to the end of any other cable or metal part while jump-starting the car.

All radiator hoses, exhaust pipes, manifolds and mufflers can be hot after the car has been running, even if for just a short while. Allow time for these parts to cool off before working on the car. If there is some reason that you can't wait, wear heavy gloves and be very careful (you can spit on them to see if it sizzles, but this only indiciates boiling hot).

DO NOT remove the radiator cap in one turn. Turn it slowly to half off and allow the steam to escape. Always use gloves or a rag. When the steam has escaped, turn the cap off fully. Always keep your face turned away from the radiator cap.

Loose clothing can easily be pulled into moving machinery parts. A loose shirt cuff, necktie, dangling jewelry, frilled blouses, or long hair can all be pulled into a moving part while making repairs. Be sure to remove such hazards before starting work. You should always wear a sturdy pair of shoes or boots to protect the feet.

Exercise caution when jacking up a car for repairs. The jack may collapse while holding up the car. Never crawl under a car that is jacked up without using a purpose-built jack stand rated to support the weight of that car. Using metal drums, buckets, bricks, concrete blocks, or wooden assemblies in the place of the jack stand, may cause a collapse.

Stabilize the car before fixing a flat tire, so that it won't jump the jack or roll. Park the car on level ground and put the car's automatic transmission into "park"; or the manual transmission into reverse, and set the parking brake. Before jacking up the car, place a brick or 2 x 4 in front of the front wheel & in back of the rear wheels that will stay on the ground (opposite the jack) to prevent rolling.

When jacking up a car on roads with truck traffic, allow for the force of the shockwave or air current created by a large vehicle speeding past, which may be enough to topple a car reting on a jack.

Prevent anyone slipping on oil, gasoline or other leaking fluids by wiping up all spills immediately. Be particularly careful when wiping up flammable or chemical fluids.

Gasoline, brake fluid, and certain cleaning fluids used in repairing an automobile are very combustible and should always be stored in closed containers designed for the purpose; these should also be well marked and stored safely (in a metal container, away from heat or any source of ignition). Use care, that spontaneous combustion does not occur.

Smoking and open flames should always be avoided while working on a car. The only person using a blowtorch should be a trained professional.

Serious car problems on a car still under warranty should be referred to garage, since any attempted repairs to a major part could void the warranty.

Never attempt repair of a car problem unless you know what is wrong and how to fix it. Car first aid is for emergency and basic repairs only, and should be done only as recommended by the car's Owner's Manual. Take major problem to a mechanic, to save yourself an even higher repair bill for correcting your mistakes.