Through the Clouds
Q: I have a 2000 F-150 XLT that puffs blue smoke after it's been driven a reasonable distance, about 110-150 miles. This occurs when it sits overnight. Sometimes it comes out in small quantities, but other times my truck spits out a cloud. I've taken it to the dealer three or four times, and they can't seem to duplicate the problem. I've discussed this with independent mechanics, and they're sure it's being caused by defective valve-stem seals. It doesn't do this during everyday driving, and up until recently it didn't use any oil. However, I checked it the other day and the oil level was at the "Add" line. The engine is the 4.6-liter Triton and has 36,000 miles on it. It first started doing this at around 12,000 miles.
A: The Ford 4.6-liter V-8 doesn't seem to have any inherent oil-consumption problems. A common cause of blue smoke from the exhaust when starting the engine is indeed worn valve seals. These are rubber O-rings that prevent excessive oil from traveling past the valve guides and into the engine's combustion chamber. Worn valve guides or valve stems also will produce similar symptoms. Another cause of blue smoke from the tailpipe on startup can be an excessive buildup of sludge, more common in neglected engines. The muck and mire can prevent oil from draining back to the oilpan. This actually can keep the valve guides completely submerged in oil. Valve-seal failure typically occurs in high-mileage engines due to normal wear and tear. But a properly maintained engine with low mileage directs us toward a premature failure or factory flaw. Speak with the service manager about the situation. It's important to duplicate the problem for the service-department personnel. Take the truck for a long ride and leave it at the dealership overnight. You may want to come down in the morning so everyone can observe the blue smoke over a cup of coffee. Once the condition is confirmed, the technician should check the PCV (Positive Crankcase Ventilation) system for proper operation and perform a compression and/or cylinder-leakage test to help diagnose the cause before disassembling the engine for further inspection and repair.
Window-Motor Mayhem
Q: I have a 2002 Ford Explorer Sport Trac with a power window that has intermittent problems. Occasionally on hot days above 80 degrees F, when the truck is parked in the sun, the right-rear power window stops working. I've taken the truck back to the Ford dealership three times, to no avail. The first time, they rewired the power window, the second time, they replaced a switch, and the third time, it worked when I brought the truck in so there was no issue, according to them. I'm guessing the rear power-window motor is the culprit, but how do I convince the service department?
A: A common cause of intermittent power-window operation often is the motor itself, which the dealer should've replaced the third time around. If you're in the area while the window isn't working, get it to the dealer ASAP to prove your point. An old-fashioned but reliable diagnostic method is to apply the switch and lightly tap the motor with a hammer while the window is inoperable. If it comes back to life, junk the motor. Otherwise, ask to speak with the dealership's service manager, and, if necessary, the Ford service-zone representative.