Bottom Line
Maintenance Q&A
Is it time to buy?

By Paul Abelson
Senior technical editor


Q: I have a 2002 Pete 379 with 740,000 miles. Repair bills are starting to increase, and it might be time for a new truck. Which side of 2010 should I buy? Should I get one now before the 2010 engines hit, or wait and get the newer technology? I’m thinking about a Cummins engine.

A: There are always emotional factors to consider, but let’s keep this as objective as possible. First of all, going from a 379 to an aerodynamic truck, a 386 for example, will improve fuel economy up to 1 mpg. Even the traditional 389 has improved aerodynamics worth a 1/4 mpg or more, all things being equal.

Prices for 2010 Paccar family trucks will increase between $9,000 and $9,500 (list) over 2009 models, for SCR equipment. The actual price depends on your negotiating skills. If you keep your new truck for eight years (waiting to 2010 and matching the life of your 2002), you’re looking at up to $1,330 per year. That includes the 12 percent excise tax. Engine makers are claiming 4 to 5 percent better mpg with SCR. Assuming 6.0 mpg with your 379 and fuel at $2.65 per gallon, a 4 percent savings would be more than $1,800 per year, more than offsetting the increase for SCR.

The Technology & Maintenance Council has studied ownership costs and confirms that after the first three or four years, annual maintenance costs increase exponentially. The longer you wait, the higher your maintenance costs will be. And the resale value of your truck drops each model year.

Only you can evaluate these trade-offs.

Also, in 2011 new stopping requirements are expected to raise truck prices another $1,000 or more for heavier brakes.

Q: I have a 2005 Freightliner. My trailer lights turn off after three or four hours into my shift. I work nights delivering fuel. The 7-pin connector seems to be in good shape, no corrosion at either end, and tight connections. The sockets are good, too. I pull over, turn the truck off, turn it back on and the lights turn on. This happens once or sometimes twice a night. I took it to a local dealer, which had my truck five days, charged me $230, and told me it could not find the problem. Do you have any suggestions?

A: On matters electrical, I am fortunate to know Brad Van Riper, vice president of research and development at Truck-Lite. He started by admitting that it is a bit of a challenge to diagnose a problem from hundreds of miles away. Brad did have a hunch that may be worth checking.

Many trucks use circuit breakers for overload protection. These are handy devices but have a much wider tolerance than fuses, by as much as 25 percent. When you turn off the power, the circuit breakers reset.

“You either have a weak circuit breaker or you have an intermittent dead short on this circuit,” he said. “A weak circuit breaker, one that has tripped multiple times, may be tripping at lower-than-rated current.” Replace the circuit breaker if necessary.

If that doesn’t do it, check for any added lights or accessories powered from the trailer light circuits. Sometimes installers tap into lamp circuits to add lights or power other devices. This practice damages insulation and allows water and salt spray to enter wiring where it wicks through the strands. Internal corrosion can cause intermittent shorts in the wiring.

Corrosion will not be visible unless you strip away the insulation, but any such splices should be thoroughly sealed against moisture. If you cannot use proper connectors and shrink tube, brush on liquid vinyl, sometimes called liquid electrical tape, over the splice to seal it. Make sure there are no open spots or bubbles. LL


Paul Abelson can be reached at