AUTONET TV

Making Sense of the O2 Sensor (Oxygen Sensor Replacement)

As you know, today’s vehicles rely on a lot of computers in them to keep them running clean and efficiently.  Those computers depend on information delivered by several sensors throughout the engine and exhaust system.  And one of the most important is the oxygen sensor.  

Known as the O2 sensor for short, it looks for too much unburned oxygen that has made it into the exhaust. That signals something isn’t right with the engine’s air-fuel mixture.  The sensor sends signals to the engine’s computers, which can then make adjustments to make sure the engine is running as it was designed to.

Some vehicles can have several O2 sensors, and since they can measure oxygen at various points in the combustion/exhaust process, the computers can pinpoint where the problems lie.  For example, an O2 sensor can detect how much oxygen is coming out of the engine’s combustion chamber, and another one can measure oxygen coming out of the catalytic converter.

As you can see, it’s important that those O2 sensors are working correctly.  If they’re not, the computer is getting bad information.  Garbage in, garbage out. That can result in lousy fuel economy and excess pollution coming out of your tailpipe. It can also affect your vehicle’s performance.  Sometimes your Check Engine light will illuminate when one of your O2 sensors goes bad.  Or you may notice your engine misfiring or idling roughly. 

If you notice any of these symptoms, bring your vehicle on in, and a technician will pinpoint the trouble spot.  

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

A Bright Spark (Ignition Coil Replacement)

Ever wonder how your vehicle’s engine is able to take the 12-volts from its battery and ramp that up to as high as the tens of thousands of volts it takes to fire its spark plugs? The secret is something called an ignition coil.  Most newer vehicles have an ignition coil at each cylinder, but older ones have a coil that serves all of the spark plugs. 

There are telltale signs that you have an ignition coil problem.  As you might expect, one symptom is it’s hard to start your engine or it won’t start at all.  If your engine is misfiring or not running smoothly or you see the Check Engine light come on, those all could point to an ignition coil failure.

Several things can contribute to ignition coil trouble in addition to normal wear and tear. Moisture and dirt may have gotten inside the coil, plus the heat and vibration of your engine over time can contribute to them going bad.  Bad spark plugs or plug wires can also be a cause.  

While ignition coils can last 100,000 miles/160,000 km, depending on how you drive and in what conditions.  If you start noticing some of the signs and symptoms just described, it’s a good idea to schedule a visit to see us so a technician can diagnose what’s wrong. Driving too long with an engine misfiring can damage your catalytic converter, and that can be expensive to replace.

A technician will thoroughly check your ignition system and determine where the failure is.  If it’s only one coil that’s bad, it may be the only thing that will need replacing.  If your vehicle has a distributor, it may also need to be replaced.  Properly-working ignition coils will help your vehicle operate at its best and help prevent future engine damage.

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

Oil's Well That Ends Well (Oil Change Grades and Weight)

Changing your oil regularly is one of the most important things you can do to keep your vehicle running well.  And knowing the right type of oil to use is also very important. 

Engine oil is classified by weight, but it doesn't refer to how much the oil would weigh if you put it on a scale.  It refers to viscosity, or how easily the oil flows through the engine.  Most engines operate normally at around 210°F/99°C.  The viscosity, or weight, is assigned a number by how well it flows at that temperature.  The lower the number, the more freely it flows. 

Most vehicle engines use what's called a multigrade oil which behaves differently in different temperatures. Multigrade oils have a "W" in their viscosity number that you may have seen on a bottle of oil, something like 5W30.  The W stands for winter and shows how freely it flows in colder temperatures.

That means a 5W30 oil will behave like a 5 weight oil in lower temperatures (less viscous or thinner) and a 30 weight oil in warmer temperatures (more viscous or thicker).  That's important on a cold day because the oil needs to behave like a thinner oil when you start your engine since it need to lubricate engine components immediately to protect the metal components. Then as the engine warms up, it behaves like a thicker oil to prevent friction among those parts.  Pretty neat trick, right?

The type of oil you use can differ depending on what type of climate you operate your vehicle in and how your vehicle is used (carrying big loads, towing, etc.). Your owner's manual contains several different recommendations based on these factors.  Your service advisor can recommend the right oil for your needs.  Like Shakespeare said, "Oil's well that ends well."

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