Glossary

Car maintenance has its own vocabulary, most of it printed in small type on caps and bottles. The definitions below are written for drivers, not mechanics, and where a term has a Northern Nevada angle, altitude, dust, cold starts, the Washoe smog rule, the definition says so.

0

0W-20

A thin multigrade oil used by most current Toyota, Honda and many other engines. The 0W means it flows well on a freezing Reno morning; the 20 is its thickness at operating temperature. Almost always a synthetic. Full synthetic oil change

1

1G station

In Nevada DMV terms, an authorized inspection station that tests but does not repair emissions components. A quick lube that smog checks is this class; it may still change oil, filters, belts and hoses. Smog check and emissions test

2

2G station

An authorized station the DMV allows to test and to repair or adjust emissions components. Repairs after a failed test that go toward a DMV waiver must be done at a 2G station. Failed a smog check? What happens next

5

5W-30

The most common grade in older cars and many trucks. Slightly thicker than 0W-20 at operating temperature. Available as conventional, blend or full synthetic; the manual tells you which grade, the oil type is your choice. Full-service oil change

A

A/C recharge

Adding refrigerant to a system that is low, after checking for leaks. A system that needs recharging every summer has a leak that recharge alone will not fix. A/C service and recharge

Alternator

The belt-driven generator that charges the battery and runs the electrical system. A weak alternator looks like a bad battery; the battery test reads both. Slow crank on cold mornings

Altitude

Our service centers sit between 4,426 and 4,917 feet (USGS). Thinner air means less oxygen per cylinder, hotter work on grades and quicker boil-over margins, which is why mountain driving counts as severe service. Elevation of our service centers and the roads around them

API donut and starburst

The two marks on an oil bottle. The donut names the service category and viscosity; the starburst means the oil meets the current ILSAC standard for fuel economy and protection. Look for both when the manual asks for them. Synthetic vs conventional oil

API SP

The current American Petroleum Institute service category for gasoline engine oils, shown in the API donut on the bottle. SP oils protect against low-speed pre-ignition in turbocharged engines and are backward compatible with older categories such as SN. Full-service oil change

ATF

Automatic transmission fluid. It lubricates, cools and carries hydraulic pressure inside an automatic transmission. Transmissions are picky about the exact type; the manual or the dipstick names it, and some are dealer-only. Transmission fluid service

B

Battery CCA

Cold cranking amps, the current a battery can deliver for 30 seconds at 0 F. A battery loses CCA as it ages, which shows up on the first cold morning; Reno averages 122 freezing nights a year (NOAA 1991-2020). Battery check

Battery test

A load or conductance test that reads a battery's health and the charging system's output. The Car Care Council suggests testing after three years and before each winter. Car batteries and cold mornings

Blow-by

Combustion gases that slip past the piston rings into the crankcase. Some is normal; a lot means worn rings, shows as oil consumption and a dirty PCV system, and is engine work we refer out. Burning oil smell

Brake fluid

The hydraulic fluid in the brake system. It absorbs moisture over time, which lowers its boiling point. We check level and condition on the maintenance check; brake work itself is referred out. Multi-point maintenance check

C

Cabin air filter

The filter behind the glove box or under the cowl that cleans the air coming through the vents. Wildfire smoke, pollen and dust load it; the Car Care Council suggests roughly every 12,000 to 15,000 miles. Cabin air filter

Cartridge filter

An oil filter element that sits in a reusable housing instead of a disposable can. Common on Toyota, BMW, Mercedes and many newer engines. The housing cap needs the correct tool and torque. The oil filter, explained

Chassis lubrication

Greasing the fittings on steering and suspension joints that have them. Most modern cars have sealed joints with no fittings; many trucks and older vehicles still do, and it is part of the full-service oil change where it applies. Full-service oil change

Check engine light

The dash warning that the engine computer has stored a fault code. A lit light fails a Nevada smog check before the test begins; have the code read and the cause fixed first. Check engine light on

Compressor

The belt-driven pump at the heart of the A/C system. A compressor that will not engage is often a low-refrigerant safety cutoff, which the inspection checks before anything else. A/C blowing warm

Conventional oil

Oil refined from crude with a basic additive package. Lowest cost, shortest interval, suited to older engines whose manuals call for it. Many manufacturers no longer specify it for new vehicles. Conventional oil change

Coolant

The antifreeze and water mix that carries heat from the engine to the radiator and keeps the system from freezing. In Minden it has to survive 2 nights a year at or below 0 F and summers above 100 F (NOAA 1991-2020 normals). Coolant flush and cooling system service

Coolant flush

Draining the cooling system, flushing out old coolant and deposits, and refilling with the correct type and mix. Done on the manual's interval, often five years or longer for long-life coolants. Coolant flush and cooling system service

Coolant types

IAT (the old green), OAT (long-life, often orange), HOAT and P-HOAT (hybrids of the two, often yellow or pink). They are not all compatible; the manual names the type, and the color is only a hint. Coolant types: green, orange, pink and what your car takes

Crush washer

The soft metal or fiber washer under the drain plug that seals by deforming once. Reusing an old one is a common cause of a slow drip after an oil change. Oil spots under the car

CVT fluid

The fluid for a continuously variable transmission, as in many Nissan, Subaru and Honda models. It is not interchangeable with regular ATF, and using the wrong one damages the belt or chain. Check the manual before any service. What the color of your transmission fluid tells you

D

Diesel engine oil

Oil formulated for diesel combustion, labeled with API C categories such as CK-4 rather than the S categories for gasoline. Diesel pickups take more of it, often ten quarts or more, and a larger filter. Diesel oil change

Differential

The gear set that lets the drive wheels turn at different speeds in a corner. Rear-wheel-drive trucks have one at the back, AWD vehicles front and rear. Its gear oil is changed on the manual's schedule, sooner when towing. Differential service

Dipstick

The marked rod for checking oil level and color. Check it on level ground with the engine off for a few minutes. Milky oil, metal glitter or a strong fuel smell on the stick is worth a conversation in the bay. Milky oil on the dipstick

Drain and fill

Draining the transmission pan and refilling with fresh fluid. Replaces part of the fluid, is gentle on older transmissions, and is sometimes repeated over a few oil changes to freshen most of the fluid. Transmission flush vs drain-and-fill

Drain plug

The bolt at the bottom of the oil pan that is removed to drain the old oil. It is tightened to a specification and usually gets a new crush washer. A weeping drain plug is the first thing to check for small drips. Oil spots under the car

Drive cycle

The mix of cold start, city and highway driving that lets the readiness monitors complete. Usually a few days of normal driving; the manufacturer publishes the exact pattern. Failed a smog check? What happens next

E

Emissions waiver

A DMV allowance to register a vehicle that still fails after a set amount of qualifying repair at a 2G station. The DMV, not the test station, decides it. Failed a smog check? What happens next

Engine air filter

The paper or synthetic element that keeps dust out of the engine's intake. In a high-desert climate with about seven inches of rain a year at the Reno airport (NOAA), it clogs faster than in wetter places and is inspected at every oil change. Engine air filter

F

Freeze point

The temperature at which a coolant mix will freeze, tested with a refractometer or hydrometer. A 50/50 mix protects to about minus 34 F; a diluted system can freeze and crack a block on a Carson Valley January night. Winter

Fuel injector

The valve that sprays a measured amount of fuel into the engine. Deposits on the tip disturb the spray pattern, which is what cleaning addresses. Replacing injectors is repair work. Rough idle or hesitation

Fuel system cleaning

Running a detergent through the injectors and intake to remove deposits that cause rough idle, hesitation and lost fuel economy. Approved cleaners are a service a quick lube can perform. Fuel system cleaning

Full synthetic

Oil built from engineered base stocks with uniform molecules. Flows better in cold, resists breakdown in heat, and is what most current manuals specify. AAA notes many modern engines on synthetic go 5,000 to 7,500 miles between changes; the manual sets the number. Full synthetic oil change

G

Gear oil

Thick oil, such as 75W-90, used in differentials, manual transmissions and transfer cases. It takes the high pressure between gear teeth. Tow-rated trucks and AWD vehicles have a published change interval for it. Differential service

GVWR

Gross vehicle weight rating, the maximum loaded weight the manufacturer sets, printed on the door jamb. Nevada tests diesels up to 14,000 lb GVWR and exempts heavier ones. Oil changes for diesel pickups

H

Halogen bulb

The standard headlight bulb in most vehicles: a tungsten filament in halogen gas. Bulbs dim with age before they fail, so replacing both sides together keeps the beams matched. Halogen vs LED headlight bulbs

High-mileage oil

An oil, usually synthetic or blend, with seal conditioners and extra detergents meant for engines past roughly 75,000 miles. It can slow small seepage from aging seals; it does not fix a worn engine. High-mileage oil change

Hybrid

A vehicle with both a gasoline engine and an electric motor. The engine runs fewer hours per mile, so some makers set oil intervals by time as much as miles. Nevada exempts hybrids from smog checks for their first five model years. Oil changes for hybrids

L

LED headlight

A light-emitting diode headlight, standard on many newer vehicles and sold as a halogen replacement. Replacement LEDs must be the right type for the housing to keep the beam pattern legal. Headlight bulbs: halogen, LED and what fits your car

Limited-slip additive

A friction modifier some limited-slip differentials need in their gear oil to stop chatter in turns. The manual or the axle tag says whether it is required. Differential service

M

Multi-point maintenance check

The inspection that comes with every full-service oil change: filters, fluids, belts, hoses, wipers, lights, tire pressure and a look under the hood and the chassis. The technician shows you the findings and you decide. Multi-point maintenance check

Multigrade oil

An oil that behaves like a thin oil when cold and a thicker one when hot, which is what the W in a grade like 5W-30 signals. Nearly every modern engine oil is a multigrade. Reading the oil cap: viscosity grades like 0W-20 and 5W-30

O

OBD-II

On-board diagnostics, the standard port and computer system on every car sold in the United States since 1996. A Nevada smog check reads it for stored trouble codes and readiness monitors. Check engine light on: can you pass a smog check?

Oil change sticker

The windshield reminder with the next-due date and mileage. Ours follows the interval you chose with the technician from the manual; the What's due page does the math if the sticker is gone. What might be due on my car?

Oil filter

A canister or cartridge that traps particles as oil circulates. Replaced at every oil change. Spin-on filters are a sealed can; cartridge filters are a paper element inside a housing on the engine. The oil filter, explained

Oil life monitor

The dashboard system that estimates remaining oil life from miles, temperature and driving pattern. It is reset at each oil change. On many GM, Honda and Ford vehicles it replaces a fixed mileage interval. The oil change light: what it measures and why it gets reset

P

PCV valve

The positive crankcase ventilation valve that routes blow-by gases from the crankcase back into the intake. A stuck PCV valve raises oil consumption and can push oil past seals; it is a small part checked on an inspection. Low oil between changes

Power steering fluid

Hydraulic fluid in a belt-driven power steering pump. Dark fluid and a whine when turning are the usual signs it is due. Vehicles with electric power steering have no fluid to service. Power steering flush

R

Readiness monitors

Self-tests the engine computer runs on emissions systems. After a battery disconnect or code clear they show not ready until a drive cycle completes, and a smog check with too many not ready is rejected. Before your smog check

Refrigerant R-1234yf

The low-global-warming refrigerant in most vehicles built since about 2015. It needs its own equipment and is not interchangeable with R-134a; the label under the hood says which your car uses. A/C blowing warm: what a recharge does and does not fix

Refrigerant R-134a

The A/C refrigerant used in most vehicles built from the mid-1990s to about 2015. Recharged by weight to the specification on the under-hood label. A/C service and recharge

Registration renewal

The yearly DMV process to keep plates valid. In the Washoe testing area the smog result must be on file first; renewal opens online about 35 days before expiry (Nevada DMV). Renewing a Nevada registration: the steps and where the smog check fits

S

Serpentine belt

The single long belt that drives the alternator, power steering pump, A/C compressor and often the water pump. Cracks, glazing and squeal are the signs; it is inspected under the hood on every check. Multi-point maintenance check

Severe service

The driving conditions under which a manual calls for the shorter maintenance interval: towing, dust, short trips, stop-and-go, extreme heat or cold, mountain grades. Most of Northern Nevada qualifies on at least one. High altitude, mountain passes and your engine

Smog check

Nevada's annual emissions inspection, required at registration renewal for vehicles based in the urban Washoe and Clark county testing areas. A passing result is valid 90 days and goes to the DMV electronically (Nevada DMV). Smog check in Nevada

Synthetic blend

A mix of conventional and synthetic base oils. Better cold-flow and heat resistance than conventional at a middle price, with an interval set by the manual rather than the label. Synthetic blend oil change

T

Thermostat

The valve that holds coolant in the engine until it warms up, then opens to the radiator. Stuck closed it overheats the engine; stuck open the heater blows lukewarm. A repair-shop item we check for and refer. Engine overheating

Towing capacity

The maximum trailer weight the manufacturer rates a vehicle to pull. Any regular towing puts the vehicle on the severe-service maintenance schedule for oil, transmission and differential fluid. Towing, hauling and the severe-service schedule

Transfer case

The gearbox on a 4WD or AWD vehicle that splits power between front and rear axles. It has its own fluid with its own interval, checked on request during the maintenance check. Oil changes for pickup trucks

Transmission fluid exchange

Replacing nearly all the fluid in an automatic transmission by pumping new fluid in while the old is pushed out, versus a drain and fill that replaces only what is in the pan, usually a third to a half. Transmission flush vs drain-and-fill

Turbocharger

An exhaust-driven compressor that forces more air into the engine. Turbo engines run oil hotter and are the reason the API SP category exists; they are the last place to stretch an oil interval. 3,000 vs 5,000 vs 7,500 miles

V

Viscosity

How thick an oil is and how easily it flows. Engine oil viscosity is written as a grade such as 5W-30; the lower the numbers, the thinner the oil at that temperature. Your manual names the grade your engine was designed for. Reading the oil cap: viscosity grades like 0W-20 and 5W-30

W

Wiper blade

The rubber element that clears the windshield. Sun and dust harden it; streaking, chattering and skipping mean it is due. Conventional, beam and hybrid styles fit different wiper arms. Windshield wiper blades

Written estimate

Under Nevada's garage law, a signed written estimate for repair work above the statutory amount, with authorization before any extra charge. It is why the technician asks before adding anything to the ticket. What it costs