Q: When car
shopping, do you think it is important to consider if a vehicle has
a timing belt or timing chain? After seeing friends pay hefty
charges for timing belt replacements, I wonder why timing chains are
not more widely used.
— Scott M.
A: There is a
shift occurring where some manufacturers are going to chain drive
for the camshaft/crankshaft connection in addition to those that
already run them. Timing belts are lighter, quieter and supposedly
less costly to build, but they burden the vehicle owner with
replacement cost, typically at 60,000 to 100,000 miles. Timing belt
failure can also be an expensive catastrophe on interference engines
if valves and pistons collide. A timing belt replacement job
typically includes renewing belt tensioners and the water pump, if
driven by the belt. Cost can range as high as $1,000. A timing chain
may eventually require replacement as well, at similar or higher
cost, although many are claimed to last the life of the engine.
Excessive noise is the tip-off a chain system is worn and heading
certainly take a look at this when choosing a potential vehicle, new
or used, but there are many other factors to consider as well.
Q: I recently
encountered a scary situation. I was braking really hard on a long
downhill stretch, and the steering wheel and entire front of the
truck began severe shaking. I had never encountered this before or
since. What could cause this?
A: My hunch is
you have two issues at hand: brakes and steering/suspension. Your
brakes were possibly hot, and this magnifies the effects of brake
rotor thickness variation/runout/hardspots. This is what set up the
shake, and you’ve likely got some wear in steering components such
as idler arm/center link/tie rod ends that amplified the effect. Are
you seeing unusual tire wear or wandering over uneven pavement? I’d
get the truck into a brakes/front end oriented service facility for
inspection right away!
Q: My battery
light has been coming on for short periods of time and then turning
back off again in the most unpredictable manner. Sometimes it will
go for weeks without happening. I’ve taken it in twice and nobody
knows what to do. How worried should I be about this?
— April B.
illuminated (battery symbol) light indicates a fault in the vehicle’s
charging system. If the alternator (charging device) is not
producing adequate electricity to operate all the systems at hand,
the battery will soon discharge. This could lead to a breakdown or
failure to restart after parking. It doesn’t sound like you’ve
noticed any low-battery symptoms, so the illuminated light may be
somewhat of a false alarm, or the fault occurs only briefly.
inspection/testing of battery terminal connections and alternator
connections is a good place to start. Unless something turns up, an
accurate diagnosis will unfortunately need to be made during one of
the episodes. An inexpensive voltmeter placed across the two battery
terminals during an episode could bring some piece of mind or
expedite a roll-the-dice repair attempt. Normal battery terminal
voltage/engine running should be 13.5 to 14.5 volts. 12.6 volts or
less indicates no charging is occurring.