Thursday, August 8th, 2019


Myths and truths have been around since the car has been rolling, so here are some questions, lets see how good you are.

Will driving with your windows down cause you to use more fuel than with the windows up and the A/C on?

Depending on the aerodynamics of the vehicle and the speed of which you are driving, having the window open without a way for it to escape can cause enough extra drag to make your engine have to work harder. Today’s vehicles A/C are so efficient now and the fuel trim so regulated that if you are driving at speeds over 55mph it would be more efficient to use the A/C.

Running with the blower motor at its highest speed is good to keep the A/C working best

Actually, by running with the fan speed at its highest speed you are causing a higher load on the engine thus making the charging system work harder to maintain the demand. Also by keeping the blower speed at it’s lowest level can actually gain you an additional 8-9 degrees of coldness from the center vent by allowing the air to stay in the evaporator case for a longer period of time to remove the heat from the air passing through it.

Vacuum leaks in early fuel injected engines make the engines race because of the extra air in the combustion chambers

Todays newer and more controlled engines can compensate for the extra or unmetered air that enters the combustion chambers via the oxygen sensors and the fuel trim. They allow the injectors to add extra fuel to keep the engine running as smooth as possible and bring the idle down to its normal spot via the idle air control motors. Many times, the owners do not even know that the vehicle is running lean except for the check engine light that will show a lean code.

Synthetic oil is actually mineral oil that has been reengineered and synthesized with additives

True synthetic oil such as Mobil 1, Amsoil, Redline, and Royal Purple are truly synthetic. They are made from refined hydrocarbons such as animal fat, rapeseed oil methane and biomass by products. Because these molecules are combined and reengineered to be exactly the same size and identical in their lubricating qualities. Imagine that the molecules of oil are like little ball bearings chained together. Also because these molecules are identical and synthesized they have less of chance to join together and thicken the oil or turn to sludge. That doesn’t mean forever oil, just so you understand.

You should never let the pressure in your tires exceed the number stamped on the side of the tire no matter how hot that tire may be

The number stamped on the side of the tire is rated for a cold tire, meaning that it has sat for between 4 and 8 hours before being moved. Most new vehicles have the exact tire pressures posted on the front left door pillar. These are the pressures that the tires should be set at , once again cold. Expect those pressures to increase by up to 3 psi after the vehicle has been driven for even a short distance. This means that if you drove to a gas station that has a air compressor, lots of luck with that, armed with your credit card insert your card in the machine , read the tire pressure placard on the door panel, if it says 32 psi, inflate your tires to 35psi and you should be close. Or come to Gregg’s Automotive where we still do for you and it’s free.