Smelly Air Conditioner Is Easy to Fix

I get a lot of calls on my radio shows every week about cars and car care. Here are some questions and answers typical of the most recent calls.

Question: It’s been a long, hot summer, and every time I turn on my car’s air conditioner, I notice a strange smell coming out of the vents. Also, sometimes, when I first turn it on, there seems to be a mist blowing out. What gives?

Answer: The mist one is easy. With our El Nino-related summer weather this year, you’ve noticed that along with the heat we’ve had enough humidity to make Miami Beach proud. The mist you see is simply the air conditioner working overtime to get the extra humidity out of the air and not being able to remove it all before the air recirculates back into the cabin. Nothing to worry about here.

Now for the strange odors. Assuming you haven’t been indulging in some new and unusual fast foods, that smell is the result of a buildup of mold and mildew in the hoses of the air-conditioning system. How to fight it? The same way you fight it at home: with Lysol.

Turn on the engine and the air conditioner (on the “normal” setting), exit the car (make sure you’re out of gear and the parking brake is on) and spray some plain Lysol into the air intake vents, which on most cars and trucks are located where the windshield meets the top of the hood. But don’t overdo it. A few one- or two-second sprays should clear up that odor problem--and at the same time help your allergies, which the mold and mildew might affect.

Q: I recently bought a full-size sport-utility with a V-8 engine, and the mileage I am getting is lousy. Nowhere near what the window sticker says I’d get. Is there something wrong?

A: You go out and buy a 5,000-pound truck with a V-8 engine, and now you complain about the mileage? Sport-utes are different from cars in a lot of ways and, well, this is simply one of those ways. When gas prices start going up again, look for a lot of almost-new sport-utes for sale at very low prices.

There are a few things you can do to get better mileage, tricks that apply to all vehicles but that could make a dramatic difference in your sport-ute. First, use the lowest-octane gas you can get away with. I don’t care what the manufacturer recommends--if you use 87 octane instead of 91 and the truck runs fine without pinging or knocking under hard acceleration or when going uphill, then stick with it. You won’t need to use the higher-octane gas until the engine starts exhibiting some problems, which it may never do. Right off the bat, that will save you some money.

Next, helping the engine breathe better will not only gain you extra mileage but can also increase the horsepower while remaining well within emissions standards. The simplest way to accomplish this is with some bolt-on products on either end of the engine, at the intake and exhaust sides.

Replacing the stock air filter with a high-performance aftermarket air filter, especially a washable one that will last the life of the vehicle (cost: about $50), can help get more air to the engine, and that improves efficiency and mileage.

Next, replacing the stock exhaust system (from the catalytic converter back) will help mileage and performance. These bolt-on systems are available from a variety of manufacturers (check out the ads in most truck magazines). They cost anywhere from $300 to $750. Many truck and sport-ute owners, however, believe that the high cost is justified by the fuel savings and horsepower enhancement.

Q: It seems every time I take my car to be serviced for anything, the mechanic checks my wheels and then tells me I need new brake pads. He says my car would be dangerous without new pads, and I don’t want to have an accident because I neglected the brakes. Why do my brake pads keep wearing out so quickly?

A: They may not be wearing out all that quickly. You may be getting ripped off. Unscrupulous mechanics can easily play on your emotions to have you order parts and work you may not need. What parent, for instance, is going to put his or her kids in a car or truck someone has just deemed “unsafe”?

In normal use in Southern California driving (for the average driver not regularly involved in freeway pursuits or drag racing), the pads on your disc brakes should last as long as 20,000 miles without needing replacing.

Remember that pads are used only on disc brakes; drum brakes do not have pads, so find out what kind of brakes you have before going to the mechanic (check your owner’s manual for the answers). Most modern cars and trucks have front-wheel disc brakes and rear-wheel drum brakes.

If your brakes seem to be OK, if the pedal is not going farther down to the floorboard than usual when you step on it, if there are no warning lights about the brake system on the dash, if you do not notice a grinding noise or vibration when you step on the pedal, you probably do not need brake pads.

And incessant squeaking is not necessarily a problem. That squeaking can be an inherent part of any disc brake system, and in fact most people who get new pads will notice more squeaking than with the old ones.