| by Bob Weber | |
(2007-10-16) |
More mechanical wisdom from Bob Weber
Drain plugs
Q--The A/C on my 1999 Chevy Blazer will come on for a few minutes then will start blowing hot air. Then sometimes it will come on and work for quite a while. What's the problem?
A--I suspect that the evaporator (the heat exchanger behind the dash) may be icing up. Moisture from the air collects on the fins, turns to ice and blocks airflow. Sometimes, this will be accompanied by water on the floor as the ice melts or moisture may come from the vents. The most likely cause is a plugged drain in the evaporator housing preventing the water from draining on the ground like it is supposed to.
Piston slap
Q--I have a 2006
A--Although it may sound like lifter noise, I don't think it is. Lifters usually quiet down after a few seconds. I suspect the noise to be piston slap and, while annoying, does not usually lead to future problems. If it really bothers you, become a pest at the dealership. Then, should something later go wrong, you have a history of reporting it and can say, "I told you so."
Wiper motor failure
Q--I am an owner of a Dodge 2005 Grand Caravan, which had a recall for faulty front windshield wiper motors. After receiving the recall notice, my wife made an appointment and took the van to the dealer where it was purchased. The dealer said that the wiper motor was fine and did not need to be replaced. I thought the purpose of vehicle recalls was to make the needed replacements or repairs? Is there a way to determine if our wiper motor is good or bad? I would hate to have it go out on the highway during a strong rain. It has been awhile and now I am getting anxious.
A--If you check out this recall at the National Highway Traffic Safety Administration site www.nhtsa.dot.gov you will find recall number 06V067000 that explained the windshield wiper motor armature may break which, of course, would cause a loss of wiping. In NHTSA's words, "…the driver's vision could be obscured which could result in a crash."
It also said that "dealers will inspect and replace the windshield wiper motor free of charge." Yours must have check out okay. For more information, you may call Chrysler at 1-800-853-1404 or the NHTSA vehicle safety hotline, 1-888-327-4236.
Simple oil changes
Q--Your remarks about reducing oil shortages by changing one's oil less often brings up another: Is motor oil genuinely recyclable? If so, couldn't an owner change oil as often as desired, with little or no net loss to the supply, if he or she simply made certain his or her used oil is recycled? Or (as usual) is this way too simple?
A--As you surmised, nothing is as simple as it seems. Yes, oil is recyclable, but the story does not stop there. Some of the oil is consumed by your engine, some is lost during shipment and much of the used oil is used as a fuel. For example, many shops have waste oil heaters. Some of it is re-refined and put on the shelf to see service in another engine, but it must be clearly labeled as such. It also takes about a gallon of used oil to produce 2.5 quarts of re-refined oil.
Shop rentals
Q-My husband and I recently moved to
A--This has been tried, but is one of those great ideas that just didn't pan out. Typically, shop facilities were set up including tools and equipment to rent. Some even had shop manuals and a supply of common parts plus an expert to consult. About the only thing they did not have were customers. Of course, one of the biggest drawbacks is liability. There are lots of ways to get hurt working on an automobile. The DIY repair shops didn't last long.
No premium
Q-- I bought a 2001 Ford Taurus SE 3.0-liter V-6 with 165,000 miles on it. I have changed the plugs, plug wires, and coil pack, and had the Ford dealership clean injectors. The car does not smoke at startup or any time. It runs smoothly and very quietly.
I'm pretty sure that it was a fleet car. I don't know what oil the previous owner used. I changed the oil using Valvoline 5W-30. It is due for another oil change. Since the car is running so well, but has such high mileage, should I change it to Valvoline MaxLife, use what I used previously, or even consider synthetic oils?
Also, is there an additive that you would recommend be added when I change the oil? What do you think about Marvel Mystery Oil, as I have used this on a '79 Ford pickup with a 300 straight six that has 205,000 miles on it? It ran rather rough, with poor gas mileage, and I used Marvel Mystery Oil in both the gas and crankcase. That seemed to improve the performance of the truck.
A--Marvel Mystery Oil is a very light oil that works well as a top engine lube and cleaner and is fine if you don't overdo it. As for the oil you pour into your crankcase, I suggest going with MaxLife or another of the senior-citizen-car oils since they have additives that help protect the seals that could eventually leak.
At this age, synthetic oil may not be worth the premium price.
Due to the large volume, Bob Weber is unable to answer most questions sent to The Car Connection each month. Some may be answered directly, where possible, and others will be included in future columns if the topic is deemed interesting. Be sure to include your real name and full address (city, state, province, country, etc.) when sending your questions.
Weber, a self-proclaimed swell guy, is an ASE-Certified Master Automobile Technician, freelance writer, and former editor of Super Automotive Service magazine. His column, "Motormouth," appears weekly in the Chicago Tribune. He enjoys good tequila, good cigars, and good times. A chemistry school dropout, he still concocts compounds in the kitchen and makes a mean pot of chili. He and his wife live near the Blue Ridge Mountains of
E-mail Bob your questions at Mechanic@thecarconnection.com.
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