AUTONET TV

Rotation Explanation (Tire Rotation Patterns)

You may notice that when you get your vehicle's oil changed, your service adviser may recommend that you have your tires rotated at the same time.  The reasons are simple.  That will allow your tires to wear more evenly and reduce the noise your tires make as you drive down the road.

There are different ways of rotating tires. If your vehicle has non-directional tires and the same size wheels at each corner, here are the different rotation patterns.

For all-wheel drive and rear-wheel drive vehicles, one is called the rearward cross pattern.  The rear tires are moved to the front and stay on the same side of the vehicle, and the front tires are moved to the rear on the side opposite of where they were on the front. 

For all-wheel and four-wheel drive vehicles, use the X pattern.  The rear tires are moved to the front on the opposite side of the vehicle, and the fronts are moved to the rear on the opposite side of where they were on the front.

For front-wheel drive, there's the forward cross.  The front tires are moved to the rear wheels on the same side of the vehicle as they were on the front and the rear tires are moved to the opposite side of the vehicle than they were on the rear. 

If you have directional tires (they only can be mounted in one direction) and the same size directional wheels, the rear tires are moved to the front on the same side of the vehicle where they were, and the front tires are moved to the rear on the same side they were on the front.   And if you have tires with different sizes of non-directional tires and wheels on the front and rear, rotation will be from one side of the vehicle to the other. 

If you have a spare, it's put into the rotation using a forward cross or rearward cross. 

Yep, that's a lot to keep straight.  So, we suggest letting your service advisor recommend the right rotation pattern for you at the interval your vehicle's manufacturer specifies.

Gilmore's Auto Service
2151 N Broadway
Walnut Creek, CA 94596
(925) 939-9430
http://www.gilmoresauto.net

Chilly Warning (Diagnosing a Noise in Cold Vehicle)

When the weather gets colder, sometimes the noises your vehicle makes will change.  For example, you may notice a whining sound when you get going in the morning.  It may go away when the vehicle warms up, but it's best not to ignore that sound because it could be a warning of worse things to come.

Colder temperatures cause different components to behave differently.  Let's take a look at a few of them.  First, the fluids in your vehicle.  Cold temperatures can make them behave a little differently, such as engine oil, transmission fluid and power steering fluid. Those characteristics could change if the fluids are older and full of contaminants.

Belts also can create a whining noise when cold.  Since they turn pulleys that move other things, several factors can create issues.  Increased friction can change proper tensions on belts.  Plus, belts change as they age and may crack, get loose or develop a glazed surface. Belts and pulleys also must be aligned properly to work the way they're designed to.

As you can imagine, it's easier for a technician to diagnose a noise if the vehicle is making it.  And if a vehicle only makes a noise when it's cold, that sound may be gone by the time the vehicle makes it to the repair facility.  That means a driver may have to consider dropping off the vehicle the night before so the technician can be the first to start it the following morning.  Most service facilities can accommodate that with either a drop-off box or other arrangement.  Heed your vehicle's warning when you start to hear unusual noises.  That's a cool idea you should be able to easily warm up to.

Gilmore's Auto Service
2151 N Broadway
Walnut Creek, CA 94596
(925) 939-9430
http://www.gilmoresauto.net

It's (Not) Complicated (Engine Air Filter)

While many components of your vehicle are complex and composed of lots of mechanical and electrical parts, there's one that isn't complicated but still important.  It's your engine air filter.

(And, we should point out, the engine air filter isn't to be confused with the cabin air filter.  The cabin air filter cleans air that goes into the passenger compartment while the engine air filter cleans air that goes into the engine itself.)

Why does your engine need a filter? Think of all the stuff–dirt, dust, and debris in the air¬–that gets kicked up on the road.  If that were to go unfiltered into your engine, it could damage other components.

There are many different materials used in an engine air filter, including paper, cloth (frequently cotton), and other synthetic fabrics.  The material is usually folded tightly to maximize the filtering capability over a relatively small surface.  

Before computers were employed to determine the proper mix of air and gasoline, a dirty air filter could contribute to a decline in fuel economy.  But a study of engine air filters done by the U.S. Department of Energy in 2009 found that in modern fuel-injected engines, computers can maintain the correct air/fuel mix even when an engine air filter is really dirty, minimizing effects on fuel economy.

That same clogged air filter, though, can affect your vehicle's performance, mainly how much power and acceleration it delivers.  In testing three different vehicles, a dirty air filter made the vehicles slower by about 6-12%.  That's something you'd definitely notice if you were driving.

But it happens slowly, over the course of several months, so you might not even know your engine air filter is dirty unless you bring it to us and have a technician inspect yours.  

There are many different types of engine air filters, from the ones made by the original vehicle manufacturer to aftermarket ones.  Some can increase your engine's performance; some can be washed and re-used but are generally more expensive.

Your service advisor can recommend several options for you, depending on the type of vehicle you drive and your driving habits.  Dirty, dusty roads will require more frequent engine air filter changes than cleaner drive routes, and each vehicle manufacturer recommends when your filter should be changed.  Keeping it clean will help your engine breathe a little bit easier.

Gilmore's Auto Service
2151 N Broadway
Walnut Creek, CA 94596
(925) 939-9430
http://www.gilmoresauto.net

Why You Have an O2 Sensor (Oxygen Sensor)

If someone asked you what gas made up the largest portion of the atmosphere, what would you guess? Well, it's not oxygen; it only makes up 20.9 percent.  But since we're talking about oxygen, you should know that your vehicle uses oxygen sensors to make sure your engine is running the way it should.

The oxygen sensors measure how much oxygen is in your exhaust.  If there's too much, it means there's a problem with the mixture of fuel and air.  The sensor sends signals to computers in your engine and adjusts the mixture so it maximizes performance and efficiency.  It does this constantly. 

Many vehicles have multiple oxygen sensors.  Some have one close to the engine, another close to the muffler.  Two measurements are better than one since they allow readings to be more accurate.  You may have a vehicle with a dual exhaust, so you'd have twice as many oxygen sensors.

Your oxygen sensors can fail.  One thing that can damage them is contamination from bad fuel.  The sensors can simply wear out, though they usually last a long time.  It's not unusual for an oxygen sensor to last 100,000 miles/160,000 km. One more thing that can cause an oxygen sensor to fail is residue from an engine that's burning oil.  Plus contaminants from the road like salt can also cause problems. 

Here are some signs that your oxygen sensors might be failing.

• The Check Engine light goes on.  In this case, your service facility can plug in a device that will read the code in your engine's computer to see if that's the problem.
• The engine is running roughly.
• Black, sooty smoke is coming out of your tailpipe.
• Your fuel economy is noticeably lower than it used to be.

Head to your service facility and tell your advisor what symptoms your vehicle is experiencing.  They have the equipment and training to track down the issue.  Note that simply replacing the oxygen sensor is often not enough since it doesn't get to the root of the problem; other repairs may be needed. 

So make sure your oxygen sensors are working the way they should be.  Oh, and back to the question of what gas makes up most of the Earth's air?  It's nitrogen, which comprises 78 percent of the air we—and our engines—breathe.

Gilmore's Auto Service
2151 N Broadway
Walnut Creek, CA 94596
(925) 939-9430
http://www.gilmoresauto.net