The automotive world has its own language. And it’s easy to get lost in the many mysterious car terms so commonly thrown around. This language barrier is intimidating for a beginner, but it can also be a problem for Do It Yourselfers with a few successful projects under their belt.
We’re here to jump start your education for your next project with 5 basic car terms every DIYer needs to understand. You may be surprised how simple they really are.
Every car needs electricity to operate. The initial zap to get the engine going comes from the battery, but once the engine is running, the necessary electrical current is produced by the alternator. An inoperative alternator will leave a car stranded when the battery has been drained and there’s no electrical current to provide a spark to the engine.
Usually driven by a belt connected to the engine’s crankshaft, the alternator got its name because it produces an “Alternating Current” (AC) that reverses direction and magnitude regularly. Early cars used a generator that generated “Direct Current”. But AC won the current wars back in the 1960s.
For the DIYer: alternators are almost always outside the engine itself and can be accessed and changed relatively easily with some simple hand tools.
Engines with electronic fuel injection – which is virtually every car and truck built since 1990 – require a precise amount of air flowing into the engine so the amount of fuel needed can be delivered by the computer controlling the injection system. The mass air flow sensor measures the volume of air entering the engine so the computer can calculate the proper air/fuel mixture.
A malfunctioning MAF will normally throw a code to the computer which in turn will trigger a “Check Engine” light on a car’s dashboard. If the MAF is incorrectly starving the engine of fuel, this “lean” condition will reduce power output, often result in clattering engine knocks and could potentially destroy the engine. Conversely, if the engine is getting too much fuel, it runs “rich” leading to excessive fuel consumption, carbon build up and, again, engine damage.
For the DIYer: the MAF is usually located near the beginning of the intake tract after the air filter, but before the intake plenum itself. It’s most often a self-contained unit that can be easily cleaned or swapped out to correct the issue.
At the dawn of engine pollution controls in the 1970s, the EGR was one of the first. An exhaust gas recirculation system takes a portion of the exhaust gases an engine produces and directs them back into the intake manifold to be reburned by the engine with the fresh air/fuel mixture.
This process lowers combustion temperatures and reduces the amount of nitrogen oxide compounds produced, decreasing harmful emissions. Located between the exhaust manifold and the intake manifold, the EGR valve is commonly vacuum operated on older vehicles and almost always electronically actuated in newer ones.
For the DIYer: a malfunctioning EGR valve can lead to a wide range of poor engine performance, including hesitation during acceleration, reduced engine output and stalling. Sometimes this can be corrected with some simple cleaning. Sometimes it can be fixed by reconnecting or jiggling a loose wire that’s sending erratic signals. But replacing an EGR valve is often the easiest way to correct the problem and it’s (usually) an easy and cheap parts swap.
In liquid-cooled internal combustion engines, the thermostat controls when coolant is circulated through the radiator and into the engine. It’s literally a thermometer that opens a valve when triggered by excessive heat. The thermostat commonly allows the engine to build up heat at start up, and then allows the flow of coolant, along with airflow, to regulate engine temperature.
When a thermostat fails, the engine can overheat, reaching temperatures north of 230 degrees Fahrenheit. This will quickly lead to catastrophic engine failure (burned pistons, blown head gaskets, etc.)
For the DIYer: replacing a thermostat isn’t very complicated or expensive, but the job must be done when the engine is cool. A steaming radiator is a dangerous kettle; literally building pressure and threatening to scald anyone who approaches it carelessly. The thermostat is usually positioned near the top of the engine where the radiator first feeds coolant to the engine block.
All gas-fired vehicles built since the 1996 model year incorporate this second-generation vehicle emissions equipment monitoring protocol and use a standard diagnostic port to report conditions from on-board computers. The OBD-II scanner port is often a 16-pin electronic connector located under the vehicle’s dash near the driver’s knees.
The OBD-II system generates five-digit Diagnostic Trouble Codes (DTC) codes according to standards set by the Society of Automotive Engineers and classified according to the affected portion of the vehicle. These codes can tell you what’s wrong with your car.
For the DIYer: to read the codes you’ll need a scanner, which are available online or at any big box auto parts store. Prices range from about $20 for the most basic to $500 for professional units.
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