This page last modified on:
04October2004



What It All Means:

One of the biggest problems facing the mechanic is semantics. Because English is such a powerful language, it allows us to express ideas and variations that would be impossible in many other languages; a clank is different from a clunk, a shimmy is different from a shudder, a squeal is different from a squeak, a scrape is different from a grind or a growl, a thump is not a thud, you get the idea . . .

These terms have special meanings to most mechanics, and misunderstandings can cause wasted time chasing the wrong symptom, which translates to wasted money for you. When you are talking about your particular problem or symptom, it is helpful if you use the proper words to more clearly communicate your meaning.

Mechanicspeak:

TERM:
TRANSLATION:
Battery:

Batteries are very simple once you understand their needs. All a battery needs is wet plates and good, clean, tight electrical connections. Batteries are filled with sulfuric acid when they are manufactured, and don't need anything but water from then on. Think of a battery as a storage container for electricity. When a battery is charged, a minute portion of the fluid inside is changed to gas(hydrogen and oxygen), which is released from the vents at the top. After a while, the level inside the battery drops lower and lower, eventually exposing the plates inside it to the air, which causes them to oxidize. This is not good. Only plates that are immersed in fluid can hold electricity properly. In the olden days, you just removed the caps and added water until the plates were covered, it was part of the maintenance process. You did it a couple of times a year. Most batteries today are "maintenance free" which simply means that it is harder to check the fluid level or to add water. Some 'suit' thought of it...

BRAKE
WARNING
LIGHT:

Not to be confused with the vehicle stop lights, (which are red and at the rear of the car and come on when you apply the brakes,) this little (usually) red light is on the instrument panel, almost always has some sort of cryptic icon on it that usually incorporates an exclamation mark(!). The inclusion of the exclamation mark is not an accident, it is there to get your attention and to inform you of the seriousness of the situation. It means that there is something wrong with the brakes. The things that can normally turn on this light are: The park brake is applied, the brake fluid level in the reservoir is low, or there is an imbalance between the two brake pressure systems. This light normally lights briefly when the ignition key is in the 'Start' position as a bulb test.

BRAKING SYSTEM:

The collection of parts that stops the car. Brake pads, calipers, hoses, brake shoes, drums and wheel cylinders are all parts of the braking system. The braking system changes kinetic energy (motion) to heat energy. That is why your brakes get hot after braking. This phenomenon is what causes "brake fade" under extreme circumstances.

BUMP STARTING:

This is when you start a car that has a problem with the starter. It involves using the inertia of a moving car to turn the engine over using the gears of the transmission. (Note: it only works with standard-transmission cars) First, turn the ignition switch "ON", you should see the 'idiot lights' light up. This energizes the ignition system. Now, put the transmission in 2nd or 3rd gear, depress the clutch and get the car moving somehow (Having someone push the car is one way, coasting down a hill is another). When the car is moving at a reasonable speed, "bump" the clutch out just long enough to get the engine spinning and then push it back in immediately as soon as the engine starts, you will probably have to fiddle with the gas pedal a bit to keep it running.

CHARGING SYSTEM:

The system that generates, transports, and stores electrical energy. The alternator, voltage regulator, battery and battery cables are parts of the charging system.

CHARGING SYSTEM WARNING LIGHT:

This light comes on when your alternator output is less than the voltage necessary to maintain the battery voltage. It could be a problem with the alternator, voltage regulator, the wiring, or a broken or very loose fan belt. You needn't stop instantly when this light comes on, but you should turn off unnecessary electrical devices and start looking for a safe place to pull over to check out the situation.

CLUTCH SAFETY SWITCH:

This part was added to most standard transmission cars in the mid 70's to prevent the starter from engaging unless the clutch pedal was depressed. It was invented by GM as a safety feature. It can fail, get out of adjustment, or be bypassed. It prevents you from using the starter motor to move the car, which can be a problem if your engine stalls on the railroad tracks when a train is coming, but otherwise is probably a pretty good idea.

CRANKING:

What is happening when you turn the key and the starter engages and proceeds to spin the engine. An engine cranks before it starts. It can crank but not start, or it can start but not crank (as when the starter doesn't work, but if you bump-start the car it will run.) The origin of this term comes from the days when there was a large crank protruding from the front of the engine and you had to turn the engine over manually before it would start.

ENGINE:

That large greasy thing under the hood that turns chemical energy (from gasoline) into kinetic energy (motion) and thermal energy (heat). Not to be confused with a "motor", which is an electrical device that turns electricity into motion.

FIRE:

When the term 'fire' is used in relation to an engine, it refers to the actual ignition of the air/fuel mixture in the combustion chamber. This action results in the actual generation of power from the engine, and if it continues, the engine will start and run.

FRICTION:

Friction is the force that resists movement between two surfaces that are in contact with each other. It varies with different materials, temperature, surface smoothness, area of contact, and the amount of force pushing the two surfaces together. Friction is a very important concept to understand because it has such a profound effect on many aspects of your car, from keeping you on the road on corners to stopping and to causing engine and suspension parts to wear out.

FUSE:

Sometimes something goes wrong with an electrical part, and it starts to draw too much electricity. When this happens, the circuit is protected by a fuse. The fuse is the weak link in the circuit, so when a problem occurs, the fuse blows, and the electricity stops flowing. This is a safety feature to protect the wiring and the rest of the car from catching fire. Many mechanics will tell you that all you have to do to check a fuse is to look at it. Bullshit. I have seen fuses that visually looked perfectly OK, but were, in fact, blown. The only sure way to tell if a fuse is good is with a test light (or an ohmmeter, but let's not go there right now.)

GNAAAASH:

This is the noise that you hear when you try to start an engine that is already running. It is quite possibly the most humbling noise your car is capable of producing. It is never made when there is only one person in the car. If you only cause this noise once in your entire lifetime, it is a certainty that your spouse will be in the car when you do it.

GRUNCH:

This is the noise that most manual transmission cars make when you try to shift into either low or reverse gear too quickly. It is caused by a moving gear trying to mesh with a stationary gear inside the transmission. If you would rather not hear it, just shift into any other gear first, then (without releasing the clutch) pull the shift lever(fairly briskly) into the gear that you really want.

IDIOT
LIGHTS:

Those little warning lights on the instrument cluster that come on to notify the driver of the status of the various systems of the car. You know the ones I mean, they have tiny cryptic pictures on them, sometimes even a word or two. NOTE: They are not there for decoration! What each one means is usually found in the owners manual.

JUMP STARTING:

Not to be confused with bump-starting, jump starting uses jumper cables to start a car that has a dead battery. Here is the way I do it: first, connect a black end to the negative (-) post of the dead battery, then connect the red end to the positive (+) post. Next, connect the other red end to the (+) terminal of the battery on the running car. Lastly, connect the remaining black end to some clean metal part of the running car (NOT near the battery). NOTE: It should make a small spark, and the running engine should slow down. If it doesn't, you have a bad connection somewhere. Remove the clamps in reverse order and start over, paying attention to getting a good connection this time. Once the cables are connected, don't be in a hurry to try to start the dead car, wait a minute or so to allow the running car to partially charge up the dead battery (this is particularly important if your jumper cables are not the best quality). Try the starter, if it cranks slowly, or just clicks, check your connections and wait a little longer before trying again.

MOTOR:

A part of the car that turns electrical energy into kinetic energy. The heater fan and windshield wipers are examples of parts of the car that use motors. Some cars use motors to raise and lower the windows. The starter is a motor. Motors need electricity and a ground connection. They don't need gasoline.

NEUTRAL SAFETY SWITCH:

This is a part found on all cars with automatic transmissions. It prevents the starter from engaging if the transmission is in any gear other than 'Park' or 'Neutral'. It also turns on the back-up lights when the transmission is shifted into "reverse". It can get out of adjustment or fail.

OIL PRESSURE WARNING LIGHT:

This one only has one function, it is to inform you that the oil pressure in the engine has dropped to an unacceptable level. Several things can cause this condition, among them are: low oil level, dilution of the oil with gasoline, broken oil pump drive, or a defect in the wiring between the sensor and the light. This light should light up when you turn the ignition "on" but before the engine starts.

RIGHT &
LEFT:

This may seem silly to you, but a car has only one right side, and most parts from the left side will not fit on the right side. An easy way to remember which side is which is to realize that when you sit in the car, facing the front, right is right and left is left.

SERPENTINE BELTS

In the olden days, cars had lots of belts, alternator belts, water pump belts, power steering belts, air conditioning belts, fan belts. Now, many cars only have one belt, and it drives everything. This system is a great improvement over the old one, except when the belt fails. When that happens, the water pump stops turning, and you could burn up your engine in a short time if you continue driving. Carry a spare and know how to install it.

STARTER SOLENOID:

The starter is a motor. It is used to spin the engine fast enough to start. A motor that powerful uses a lot of electrical current. The starter solenoid is just a switch to turn that current on or off. It is operated electrically by power from the ignition switch. It's easy to find the solenoid, as it is the first object you come to when you follow the large cable that is connected to the positive (+) post of the battery. It is often mounted on the starter motor itself, but on most F*rd products it is separate. It will have two large wires and one or more small wires going to it. One of the small wires is the trigger wire, and if you connect power to the post where the trigger wire is connected the solenoid will make a loud click as it closes the connection. (It will also send power to the starter, turn the engine over and move the car if you left it in gear, and, if it starts, you are really in trouble if you left it in gear.)

STARTING SYSTEM:

A system that turns electrical energy into kinetic energy in order to spin the engine fast enough for it to start running. The ignition switch, starter solenoid, battery and starter are parts of the starting system.

SYSTEM:

A collection of parts and/or subsystems that work together to perform some function. I.e. the fuel system, the ignition system, the brake system, the heating/cooling system, the suspension system, etc.

SUIT:

Those guys and gals who work in nice air conditioned offices with windows, wearing nice suits, getting paid huge salaries to design incredibly stupid 'features' into our cars, year after year after... The sign on the door says "Engineering", but we know what they really do... They hate you, and they hate guys like me.

THREADS:

Threads are those little twisty things that you see on a screw or a bolt. They are also present in nuts. They are an application of one of the oldest principles of physics, the inclined plane. They allow you to magnify the force that is used to hold parts together. You can apply a small amount of force to a nut and the threads increase that force by a large factor and change its direction by 90 degrees, allowing you to exert a ton of force on something by exerting only a few pounds of force on the wrench. The friction of the threads is what keeps your car from falling to pieces every time you hit a bump.

TRACTION:

Traction is a measure of the amount of friction between your tires and whatever surface that you are driving on. If your car doesn't have enough traction, the laws of physics will become very important to you. Particularly the ones about a body in motion continuing to travel in a straight line...

UNIVERSAL JOINT:

U-joints are necessary at each end of a drive shaft so that the rear end can move up and down in relation to the rest of the car. They are the source of a lot of vibrations in older cars when the frequency of the vibration is faster than one vibration per wheel revolution. They are easy to check once you get under the car. ANY movement that you can see between the drive shaft and the flange that it attaches to is an indication of a bad U-joint. The trans should be in neutral when you check the joints, so make sure the car is safely supported before you get under and start shaking stuff.

WIRING:

If you could take all the wire in your car and stretch it out end to end, It would probably reach from you to the plant where your car was made. I have repaired thousands of cars by simply repairing a broken wire. The trick is in knowing which wires are part of the system that's not functioning.

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