Most motorists know that their car has an engine air filter and many of them wonder whether it really needs changing when a mechanic recommends it.
But few know that their car could have up to four filters and that yes, they need to be replaced from time to time.
One of the most obscure filters sits near the glove box of most cars. It’s the in-cabin air filter and because most people don’t know it’s even there, it’s not a maintenance item often discussed.
Jim Kreitzer, owner of Kreitzer’s Automotive Service in Enola, Pa., routinely shows his customers evidence of clogged filters as he recommends replacement.
“A lot of people don’t even know about this filter,” Kreitzer said.
Upon seeing his dirty in-cabin filter, one customer a few weeks ago said, “I was breathing that air?” Kreitzer said. “I said, ‘Yes, you were.’ ”
Even if you know how many filters your car has, it’s not always easy to see their condition without having to dissemble a few things. But it’s important to either check for yourself or have them checked for you, most notably the engine/oil filter and also the fuel and transmission filters.
Each filter is designed to keep particles from damaging important and expensive components of your car, including the engine and transmission. Clean filters mean smoother, more energy efficient operation of the vehicle, and one of them actually addresses air quality for you and your riders.
“Some cars are going to have a bunch of filters, some … have only two,” said Mark Schenberg, owner of St. Louis-based Car-Doc Automotive.
Here’s a filter primer:
Engine air filter: Every engine has one, and you want to keep them clean. Dirt, debris and dust coming into the engine compartments can lead to sub-par performance. A qualified service technician should be able to look at the condition of your oil filter during a routine oil change.
“Having an old air filter can reduce engine power, increase engine wear and decrease throttle response when you push on the gas pedal,” Kreitzer said. “You need fresh air to come in to get optimum combustion. That explosion is what makes the car go. Not changing it would be like trying to run with a clogged up nose and duct tape over your mouth.”
Kreitzer recommends changing them about every 19,000 kilometres.
Cabin air filter: These are used to filter out dust and debris from coming into the passenger compartment to keep the air healthy. Most cars have at least one cabin air filter although there are some that don’t. Kreitzer said several factors determine how often the filter needs to be replaced, such as driving conditions, dusty roads or road construction.
Fuel filter: It’s located in the fuel line and prevents sediments such as dirt and rust particles from getting into the fuel tank. It should be replaced every 35,000 to 50,000 kilometres. Some newer cars have maintenance free fuel pumps because they are located in the tank.
“Having impurities could clog your fuel injector and fuel pump,” Kreitzer said. It breaks the molecules in your gasoline down to very fine particles.”
Transmission filter: Most cars don’t have these anymore. If yours does, changing your transmission filter every 45,000 kilometres will greatly increase its performance and longevity and cut down on noise and shifting problems.
Reputable auto repair shops or service stations can advise you if one of your filters needs replacing. Many of these businesses check the filters during routine oil changes.
“(Car owners) need to check over their owner’s manual and read what that calls for,” Schenberg said. “As newer cars come around, things are going to change about them.”
Schenberg said people can change the filters themselves, but advised them to be careful regarding how much they pay at auto part stores.
“People tend to go with inferior parts because of the price,” Schenberg said. “They may not fit properly. If you bought one for $25, and you find one for $6, be careful.”