Truck Trend Garage: January / February 2009 Edition

  |   kiwi Silverado Braking illustration KIWI SILVERADO BRAKING
Q: I live in New Zealand and I'm on my third Silverado. My problem is that the front rotors on my 2005 Chevy K1500 Crew Cab overheat. The rotors develop hot spots that are blue. Even under light to moderate braking, they become extremely noisy with heavy vibration. I do a fair amount of towing. This truck has traveled 60,000 miles and I'm already on my third set of brakes, requiring a fourth set. The original set lasted 12,000 miles, then I received an aftermarket set with pads (origin unknown) and they lasted 600 miles, if that. The third set of rotors and pads were supplied out of GM Canada and the same thing happened but took a little longer. I've had the vehicle over a brake machine, to check the pressure differentials between front and rear, and by all accounts they're within the manufacturer's parameters. Should I replace them with drilled and slotted rotors? A: Why did you replace the rotors every time as opposed to resurfacing them? Also, how much trailer weight are you pulling and cargo weight are you hauling? Exceeding any of the manufacturer's maximum capacities is going to wear out your brakes fast. As a matter of fact, even below the maximum capacities, more weight is always harder on the brakes. Normal lifespan of brakes has always been a gray area due to the variables--not just because of the weight you're lugging, but also the driving habits involved. 12,000 miles on a pair of half-ton front brake pads is considered a short lifespan, but almost within the normal range. When saying the brakes are gone, we mean the front pads are down to the wear indicators and/or only a few millimeters of lining remain. Often a pulsation from the pedal while braking due to warped rotors will appear long before the pads are worn out (you can resurface rotors without replacing the pads). Getting hot spots on the rotors and pads wearing out in only 600 miles (if that's actually the case) tells me there's a major problem that should be obvious to you and/or a capable technician. Either you're drag racing while pulling a house, or there's a significant mechanical failure being missed. You've eliminated front-to-rear brake pressure differential being out of specifications as a problem. So I'd be looking for a continuous drag on the front brakes, or perhaps airflow to the brakes being blocked, be it by custom wheels or forward body modifications.   |   electrical Troubleshooting illustration ELECTRICAL TROUBLESHOOTING
Q: My 5.7-liter 1995 Chevy Silverado 2500's 100-amp alternator has recently been discharging the battery as I drive. I replaced the battery and the alternator, but the problem persists. I checked thoroughly for wires touching the block, but didn't find any. The blinkers, heater, etc. seem to work okay, but the charge gauge continues to go down until the truck finally shuts off. Any ideas where to go from here? A: Quality varies depending on where you bought the alternator and what you paid for it, so keep the possibility of a defective replacement part in the back of your mind. In the meantime, turn the ignition on and look for the generator light on the instrument cluster. Even though it has a volt gauge, it still has an idiot light. If the charging system is functioning correctly, the indicator will light up with the ignition on, and will go out when the engine is running. If it doesn't light up at all, check fuse #4 in the fuse block on the lower left-hand side of the instrument panel. If the fuse and indicator bulb are good, then there's probably a break somewhere in that circuit, or a bad alternator. This alternator is externally simple with an internal voltage regulator doing the electronic tough stuff. But it has to be cleanly bolted to the engine to provide a good ground, the circuit from the alternator to the generator light has to be working (brown wire, terminal L at the four-terminal alternator connector), and there has to be a complete high-amperage circuit (heavy gauge black and red wire) from the alternator output terminal to the positive side of the battery. A quick way to confirm the alternator's connection to the battery is to remove the output wire from the alternator and check it with a 12-volt test light. If it lights up, you're good. If it doesn't, follow that circuit to the battery and find the break. A likely trouble spot will be the blue fusible link located closer to the battery. The link is a wider section of the alternator output wire with an internal element that burns through under excessively high-amperage conditions (like a regular fuse). Sometimes the outside of a link will look good, but the element is still burned through beneath the insulation. Pull on either side of the fusible link. If it stretches, it's no good. After that, be sure the alternator output circuit has a good connection all the way to the positive battery terminal, both terminals are clean and tight, and the negative side of the battery has solid connections to the engine and the chassis.   |   choose The Right Gas illustration CHOOSE THE RIGHT GAS
Q: I have a 2003 Dodge Ram 2500 with the 5.7-liter engine. According to the owner's manual, you shouldn't use gas containing methanol. I have noticed that most of the gas stations have a decal on them stating, "Contains less than 10 percent methanol." I only use major oil company brands such as Sunoco, Shell, etc. The truck has 88,000 miles and I've had no problems with it. Is this something I should be concerned with? A: A methanol mix in retail gasoline doesn't sound right--ethanol, yes. I was lucky enough to get ahold of Joanne Shore, senior analyst with the Energy Information Administration. According to Joanne, aside from alcohol-burning race cars, she's unaware of the use of methanol in retail fuels. Either you misread the ethanol tag on the pump, or it's something we can't explain. Methanol, also known as methyl alcohol, is produced from wood, coal, or natural gas. Methanol is more volatile an alcohol than ethanol (produced from corn) and has been used to produce methyl tertiary-butyl ether (MTBE), an oxygenate that blends with gasoline. But MTBE was discontinued years back due to groundwater contamination issues. What we see now in more than half the gas pumped across the U.S. (and increasing with federal regulations) is E10, a 10 percent ethanol/90 percent gasoline blend which accomplishes two things. One, it boosts octane and decreases emissions. Two, it slightly reduces dependency on foreign petroleum. E85, the much harder to find 85 percent ethanol/15 percent gas mix, is what only flex-fuel vehicles are equipped to run on. Ethanol does have its drawbacks. Alcohol contains less energy per gallon than gasoline, so it takes more fuel to produce the same amount of power in a gasoline structured internal-combustion engine, meaning less mpg. That's why flex-fuel vehicles use larger fuel injectors and a sensor to determine the ethanol-to-gasoline ratio in the tank. Another downside is the corrosive properties of alcohol. Modified fuel lines, rails, pumps, and tanks are required to avoid corrosion of gasoline-based fuel systems. E10 is considered to be harmless to a gasoline-burning engine, but I have my doubts. Examples from several sources, including myself, indicate significantly quicker fuel contamination and component corrosion with E10 as compared to pure petroleum gasoline, especially with carbureted vehicles unused for relatively short periods of time. The scary part is that a number of states are looking to up the ante to E15 or even E20, while automakers protest knowing the effect it may have on non-flex-fuel systems. MORE NAVIGATOR SPEED
Q: I just imported a used 2006 Lincoln Navigator Ultimate 4x4 to Germany. Two issues I would like to ask you for your expertise. Speed governor: If the autobahn is packed, it is helpful to maintain the same pace as the rest on the left lane to avoid getting pushed into the right lane between trucks traveling at 55 mph. The truck seems to be capable of much higher speeds than the governed 100 mph. Question #1: What's the easiest way to disable the governor? Voiding the warranty isn't an issue, as it won't be recognized for a vehicle registered in Germany anyhow. As to maintenance, I understand there's a major scheduled maintenance every 15,000 miles; however, there are services in between identified in the service manual. Here, we service every 5000 miles, changing the oil and following a recommended multipoint inspection. Question #2: Does engine oil have to be changed every 5000 or 15,000 miles? 5000 seems ridiculously low. A: As far as kicking up the powertrain control module's speed-limitation programming is concerned, it's not going to happen with Ford's approval, but you can accomplish the task with Hypertech's Max Energy Power Programmer. This box can do a lot more than raise the speed limit--up the rev limiter, optimize for 87- or 93-octane fuel, calibrate the speedo for aftermarket tire sizes and gear ratios, and so on--but you can use only the tools you desire without affecting other OEM parameters. Important note: Manufacturers have speed limitations set to prevent the vehicle from traveling above the maximum speed ratings of the original tires for prolonged periods of time. With that said, check the speed rating of your tires and upgrade accordingly to the match the modified speed limitations. As far as service, I suggest sticking to the manufacturer's specified oil change intervals, regardless of what the Joneses are doing. The 5000-mile recommendation on your Navigator is the upper end, under ideal, normal driving conditions. In more severe conditions, prolonged idling and lots of dust, the interval is 3000. My advice is to adhere to the severe schedule, regardless, if you plan on keeping the car or truck for a long time. How To Reach Alex
If you have a technical question regarding your pickup, SUV, or van, feel free to contact Alex, a master technician with the National Institute for Automotive Service Excellence. Send a letter to him in care of Truck Trend Garage, 831 S. Douglas Street, El Segundo, CA 90245, or e-mail us at trucktrend@sourceinterlink.com. Please include the VIN with your question. Due to the volume of questions received every month, we cannot guarantee that everyone's question will be personally answered or will appear in the magazine.

Can't wait for help with a problem you're having with your Truck or SUV? Ask the expert we trust here at Truck Trend Garage--visit Alex Steele at www.RealWorldAutomotive.com.