Sludge buildup due to not having motor oil changed for at least 11,000 miles.
Bruce Archuleta, a mechanic in Phoenix, had to replace the engine on a 2003 Jeep Liberty because a buildup of oil sludge blocked lubrication passages, causing the engine to fail.
Change the oil according to the maintenance schedule (about every 7,500 miles for normal driving conditions or 3,000 miles for severe conditions). Failing to do so can cause excessive engine wear and create sludge in some engines, which forms when oil breaks down.
Timing belt was not changed on schedule.
Mike Mikulski, a Haddam, Conn., mechanic, had to replace the engine on a 2000 Subaru Outback after its timing belt broke after 150,000 miles, allowing the pistons to collide with the valves. A used engine with a new timing belt was installed, keeping the cost from being much higher.
The timing belt should be replaced as prescribed by the manual, usually around 60,000 to 100,000 miles. Many cars use a chain, which never needs changing.
Owner ignored brake noise from worn pads.
$100 to $200.
John Ibbotson, our own senior mechanic, had to replace the rear brakes on a friend's 2007 Hyundai Santa Fe because the pads had worn down to bare metal and damaged the discs. Had the job been done earlier, it might have been limited to replacing the pads and perhaps smoothing the discs on a lathe.
On many cars, when a pad wears thin, a metal tang rubs against the disc and makes a squeal, warning that it needs to be replaced. Other signals include steering-wheel shake or noises when braking. A pad inspection at each tire rotation (about every 6,000 to 7,000 miles) should also be performed.
Oil level was too low because of a leak.
$100 to $1,000.
Steve Ouellette, a Higganum, Conn., mechanic, told us of a 2004 Acura TL that had to have its engine replaced because a lack of oil kept it from getting enough lubrication. A used engine kept the cost from being much higher.
Check the oil level once a month, or every week if the car has a leak. Take your car in for service if the check-engine light is accompanied by another warning light or a change in performance. A leak caught early can be an inexpensive fix.
Fluid was too low because of a leak.
About $300 to $500.
Lance Wiggins, technical director for the Automatic Transmission Rebuilders Association in Oxnard, Calif., told us of an owner whose Mazda Protegé had a leaking axle seal. But instead of having his shop repair it, he decided to keep topping off the fluid. He overfilled the transmission, which made the leak worse. Eventually, the transmission's internal clutches burned out.
If the transmission fluid is too low, it's probably because of a leak, which should be fixed. If you add fluid, don't overfill the transmission; that can make things worse.
Engine was not tuned.
Auto-repair shop technician Frankie Jaquez in Middletown, Conn., replaced the catalytic converter on a 1999 Honda Accord—twice. The customer declined a $300 tuneup when it was first replaced and was back after 20,000 miles. The new catalytic converter became overtaxed because a dirty sensor caused the untuned engine to run too rich and it poured unburned fuel into the exhaust system.
Regular tuneups are vital for optimizing the life of drivetrain elements and producing low emissions. The catalytic converter should have lasted 100,000 miles.
Bob Simpson, district manager for an auto- glass shop in Belleville, Ill., replaced the windshield on a 2005 Ford F-150 because a small chip grew into a long crack over time.
Chips can be fixed for around $60, but in some states it's illegal to repair one in areas swept by the wipers.
Tires were not rotated.
About $20 per rotation, or $100 over 30,000 miles.
Clint Dalton, manager of a Leesburg, Va., tire and repair shop, replaced a Nissan Sentra's tires after less than 30,000 miles because they had never been rotated. Those tires, with a 65,000-mile warranty, should have lasted much longer.
Rotation is generally recommended every 6,000 miles by manufacturers. Also, check the tire pressure at least once per month; underinflation can cut a tire's life by as much as half. If your car pulls to one side, its wheel alignment is probably off, which also hastens tire wear. An alignment runs $50 to $100.