April Fools in the Auto World: A Few Laughs From the Shop

Every shop has a list of pranks customers have been told over the years. Some are gentle, some are mean, all of them are nonsense. In honor of April 1, here are the classics, the actual facts behind them, and our promise to never pull any of them on you.

Blinker fluid

The granddaddy of them all. New tech, second day on the job, gets sent to the parts counter to ask for "a quart of blinker fluid." The parts guy plays along and sends them to a different store.

The real fact: Turn signals are bulbs and relays. No fluid involved. If your turn signals are blinking too fast, it usually means a bulb is out (the flasher detects the reduced current draw and speeds up to alert you).

Winter air vs summer air in your tires

"You should switch to winter air in your tires when it gets cold." No, you should not, because that is not a thing.

The real fact: Air is air. What does change in winter is pressure. Cold air is denser, so the same amount of air in your tire reads at a lower pressure on the gauge when it is cold. You do not need different air. You just need to add a few PSI to make up for the temperature drop.

Headlight fluid

Same prank, different liquid. Sometimes called "muffler bearings" or "engine flux." All variations on the same joke.

The real fact: Headlights are also bulbs (or LEDs). The yellowing you sometimes see on plastic housings is oxidation, which a real headlight restoration kit can fix. Cloudy lenses cost you 30 to 50 percent of your light output and are worth fixing.

Summer-only oil

"Better drain that 5W-30 out and put in 30W for summer." If your car was built before 1975, sure, maybe. After that, modern multi-grade oils handle everything.

The real fact: The W in 5W-30 stands for winter. The first number is cold-weather flow, the second is hot-weather protection. A modern multi-grade is engineered to do both. Use what your owner's manual says. Period.

The "muffler bearings need repacked" line

A classic up-sell prank. There are no bearings in a muffler.

The real fact: Mufflers can rust through, develop internal baffles that come loose, or fail at gasket connections. None of that involves bearings. If yours is louder than it used to be, it is leaking somewhere. Have someone look at it.

"Replace the air in your A/C system"

"Your A/C uses 134a, but the new spec is 134z. Big upgrade." There is no 134z.

The real fact: A/C systems use either R-134a (older cars) or R-1234yf (newer cars). They are not interchangeable and the equipment to service them is different. We have both. If your A/C is weak, it is usually low charge or a failing component, not the wrong refrigerant species.

The "left-handed metric wrench"

A real classic. New tech sent to find one, comes back two hours later having checked every drawer in the shop.

The real fact: Metric and SAE are sizing systems. Threads can be left-handed or right-handed (lug nuts on some old Chrysler products are famously left-handed on one side of the car). Wrenches are wrenches.

Our promise

We will never tell you that you need blinker fluid. We will never sell you summer air. We will never charge you to repack your muffler bearings. The only fluids and parts we recommend are the ones that actually exist and the ones your car actually needs. Honesty is the entire point.

Happy April Fools. May your engine run smooth and your jokes land better than ours.