13 Must-Know Tricks to Max Out Your Road-Trip MPGs

The snows have melted, the trees are beginning to sprout leaves and the sun is visible in the sky for the first time in months. Yep, it’s finally springtime, and you’re looking forward to a road trip with the whole clan. Time to tune up the old family truckster ... right?

A generation ago, you could drop the car off at the corner gas station and ask for a tuneup. Times have changed. With federal regulations requiring car manufacturers to maintain like-new emissions output for 100,000 miles, a traditional tuneup has become a relic of the past. But that doesn’t mean you can ignore your car’s health. While fuel injection and ignition systems have been rendered nearly maintenance-free, it’s still necessary to change fluids and filters, check belts and hoses and generally poke around with a suspicious eye. There are quite a number of things you can do to improve fuel economy, too. And I don’t mean strapping on useless gas-saver gadgets or adding magic beans to your tank. A few simple calculations can help you optimize the amount of money you spend on fuel. So let’s hit the toolbox before we hit the road.

Check the Hoses

Radiator and heater hoses eventually fail. They’re made of rubber, and the extreme underhood temperatures combined with corrosive coolant degrade them. Avoid a breakdown on the road by checking them regularly. When the engine is cool, give all the hoses a good squeeze near the ends. A hose that’s failing develops longitudinal cracks inside, where you can’t see them. Roll the hose between your fingers and feel for cracks. Also, a hose nearing failure feels spongy somewhere along its length or shows a bulge. Five years is a good life span for a radiator hose.


Fluids and Brakes
Take 5 minutes and check the levels of all the fluids (oil, transmission, brake)—and don’t forget the battery electrolyte. Checking manual transmissions, rear axles and transfer cases might involve crawling under the car with a wrench and sticking a finger into the fill hole to feel the level of lube. Check the automatic transmission’s dipstick with the vehicle in Neutral and on level ground—after the car is thoroughly warmed up. And while you’re down there, make sure there’s a decent amount of brake lining left on your pads.


Filters
It’s usually pretty easy to check the air filter without any tools. If it is visibly dirty, it’ll need to be replaced, not just blown off with compressed air. Consider a cleanable, reusable K&N filter instead of buying disposable paper filters. Clean out dirt, leaves and dead bugs from the filter housing, too. Replace the fuel and oil filters as recommended in the owner’s manual.


Coolant
A proper mix, winter or summer, is 50/50 undiluted coolant to water. Increasing the concentration of coolant to water in the system raises the boiling point and lowers the freezing point. But, contrary to popular belief, extra glycol in the coolant won’t provide more protection in the winter, and could actually make your engine run hotter in the summer. Be sure to visually inspect the radiator filler neck and header tank for murky corrosion and contamination. Check the concentration with an inexpensive hydrometer when the engine is cold.


Cleanup in Aisle Three
Remove leaves, road debris, bugs, roadkill and mud from the cowl intake and the radiator. Disintegrating leaves can work their way into the heater core, causing poor heater or a/c performance, not to mention a musty smell. Dirty or clogged radiators can cause overheating.


Tire Pressures
Low tire pressures waste gas and make your tires wear out prematurely, not to mention making your car hard to control. If the outside air temp has changed with the seasons, your tires might be under- or over-inflated today. Tires can lose 1 to 2 psi for every 10-degree temperature drop. Tire-pressure monitoring systems (TPMS) are standard on all 2008 and newer vehicles. But don’t blindly rely on these devices. And don’t just wait until the light comes on. If your car uses the ABS system to calculate tire pressure by checking how many revolutions your tires make over the road, any single tire could be 20 percent (5 to 7 psi) low before the system trips and turns on the light. That’s dangerously low.

If you have a TPMS with pressure transducers in the wheels that gives you a readout of the individual tire pressures on the instrument panel, you still shouldn’t just wait for the light to tattle. It’s easy to check from the driver’s seat, so why not do it every day?

No TPMS? Tire gauges differ, especially the ones built into the pump at the corner gas station, so use the same gauge consistently. Buy a $10 tire gauge and keep it handy. Don’t forget to check the spare, too. Check pressures when the tires are cold, first thing in the morning. The recommended tire pressures are printed on a sticker somewhere on the driver’s side door, the doorsill or in the glovebox. Staying near the high end of the recommended pressure range improves fuel economy and tire wear and helps compensate for any extra weight you tote around on family road trips.


Gadget-Free Gas Saving


The summer road trip is still a part of our culture. True, gasoline ain’t getting any cheaper—but neither is air travel. Plus, have you dealt with the TSA lately? A good road trip might be more appealing now than ever before. Here are a few steps you can take to minimize the fuel bill.

> Start by shedding extra weight. Ditch the golf clubs, that bag of rock salt, the old battery you never got around to taking to the recycling center and any other junk in the trunk.

> Likewise, remove the luggage or bicycle rack that lives on the roof even when there’s no luggage or bicycle aboard. That additional aerodynamic drag at freeway speeds can reduce economy substantially.

> Be sure you’re using the correct viscosity and grade of oil. A thinner, lower-viscosity oil requires less power to pump around the engine. Auto manufacturers have re-­engineered cars to run on lower-viscosity oil to save fuel.

> Oil that is rated Energy Conserving has been tested to provide a further gain in economy.

> If you’re not seeing the kind of mileage you’d like, it might be time to check the engine’s performance. Buy or borrow a scan tool and learn what all those trouble codes and engine parameters mean. You may be able to eke some ponies out of the old bus, too. A new air filter or other minor tweak might increase mileage and perform­ance measurably.

> Finally, remember that the biggest variable when it comes to consumption is you, and the behavior of your right foot. I know, you’ve heard that mantra a thousand times before. But driving moderately and anticipating traffic (so you can lift off the gas early instead of braking) will make the largest difference in your mileage.


What's the Right Gas for My Car?
Do the math and figure out definitively which pump delivers the most miles per dollar.

It says right on the gas cap of your car: “91 Octane Only.” Some cars specify the lower-grade fuel, but your ride needs premium. Which is, of course, more expensive.

Your car may require a higher octane rating because it has a higher compression ratio, or forced induc-tion from a turbo or supercharger. As the piston travels up in the compression stroke, the space for the air and fuel becomes smaller and temperatures increase in the combustion chamber. This can cause low-octane fuel to ignite spontaneously, before the spark plug fires. The result: very high pressures, called knock or ping. Because the pressure spikes before the piston has reached top dead center, it pushes down too soon, resulting in poor engine efficiency. Prolonged knock can actually damage the pistons. High-octane fuels are more resistant to knock.

Car manufacturers protect modern engines with knock sensors. When knock starts, the engine computer enriches the air/fuel mixture to prevent damage. If you burn a lower grade of fuel than your car requires and the engine has a knock sensor, fuel economy and performance will simply drop off with no harm to your engine. The question is, do the lowered performance and fuel economy balance out the reduced cost? Here’s how to decide. (Remember: This is only appropriate if your car has a knock sensor and won’t be damaged by lower-grade fuel.) Fill up with the fuel that has the recommended octane rating (let’s assume it’s 91) and drive for a few tankfuls. Check your fuel economy by dividing the miles driven by the amount of fuel consumed.

Now try a midgrade fuel and repeat. Make sure the driving route, traffic and weather conditions are similar. If the fuel economy is just about the same, try the next lower grade. Repeat until you see a drop-off in mpg. When you do, go back up one grade (to the one that didn’t lower economy) for the best mileage.

Now, instead of dividing by the gallons consumed, divide by the cost of each tankful. This will give you the miles per dollar. If you are still saving money, reserve that better gas for times when you really need perform­ance—like for towing. On the other hand, you might find that the cheap stuff is actually more expensive per mile of road than something with higher octane.