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A Guide to the Wife's Vehicle

12:15PM Jul 08, 2008

You work on $100,000 combines and tractors without fear, but opening the hood of your wife's SUV causes you to break out in a cold sweat. What should a mechanically inclined farmer be able to do on modern vehicles?

Tony Molla is an ASE-certified technician who spent 10 years under the hoods of vehicles before becoming director of communications for the National Institute for Automotive Service Excellence (ASE).

"I don't even change my own oil anymore,” he says. "It's a matter of time—there are things that make me more money or I'd rather do than work on my vehicle, so it's worth it to me to pay a professional to do it.”

But for the inspired, Molla suggests what a vehicle owner should be able to do on modern vehicles.
Engine oil and filter changes. "You'll want a filter wrench that fits the new small oil filters,” he says. "Other than that, it's pretty straightforward. Newer vehicles have an engine oil change warning light that you'll have to reset. The owner's manual usually tells how to reset that monitor.”
Brakes call for caution. Anyone who can change brake wear components on pre-1980 vehicles should be able to handle newer vehicles. Be careful when working on master cylinders, slave cylinders or disk brake calipers with Anti-Lock Braking Systems (ABS).

"ABS work under extremely high pressures,” Molla says. "If you open a brake fitting without depressurizing the system, the brake fluid can squirt out at a high enough pressure that it acts like a liquid knife, actually slicing flesh. I'd leave anything beyond brake pads and brake shoes to a professional.”
Change spark plugs. Manufacturers brag modern spark plugs can go up to 100,000 miles between changes.

While true, Molla says, "chemical interactions between the steel threads of the spark plug and the aluminum cylinder head can weld them in place if they're left in there for a long time.”

One dealership, Molla says, "exercises” spark plugs as regular maintenance and applies anti-seize compound to the threads. Home mechanics need to use care when applying anti-seize.

"Most new vehicles have oxygen sensors in the exhaust that can be damaged by exposure to fumes from silicone-based anti-seize compounds,” Molla explains. "Don't get anti-seize on the electrodes or any part of the spark plug that will extend into the combustion chamber.”

Batteries and electronics. Changing a battery is no big deal, except many new vehicles have computer systems that need constant electrical power to maintain electronic memories. Molla suggests using a "memory saver” while changing a battery. The short-term battery plugs into the cigarette lighter to retain memory during the transition.

Hybrid hiccups. Molla also warns of the extreme dangers associated with electrical systems of hybrid vehicles.

"If the vehicle is a hybrid, powered by both a gasoline engine and an electric motor, DO NOT mess with the big orange wire,” he says. "The electrical systems in hybrid vehicles are very potent, enough to kill. So unless you know exactly what you're doing, don't tinker with them.”
Tire trouble. Be wary of tire pressure monitoring systems (TPM), which are on all 2007 or newer vehicles. Some older vehicles have them, as well.

"It may take special tools and procedures to dismount a tire from a rim with TPM,” Molla says. Leave that sort of work to a professional.

"Even if you just use a tire-plugging repair kit to fix a tire, without taking the tire off the rim, you'll still have to reset the low tire pressure warning light on the dashboard,” he says. Consult the owner's manual for details.

Know a pro. "Take your vehicle to a shop and have it thoroughly inspected at least once, maybe twice, a year, depending on the mileage you put on it,” Molla says. "The good news is, with regular maintenance there's no reason modern vehicles shouldn't last 150,000 to 200,000 miles.” 

Cool Tool of the Month

Magnetic part trays come in a variety of sizes and prices, from a 6" round tray for $10 to a 12"x12" square tray that costs about $35.

Clamp one on the toolbox that goes with you to the field. Then, you'll always have a handy magnetized place to store nuts, bolts, washers and small tools during repairs.

You can e-mail Dan Anderson at