Express Car Care of Denver

"Denver's Best Auto Repair and Quick Lube"

Oxygen Sensor

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Oxygen SensorMany people hear the term “Oxygen Sensor” and figure it must have something to do with sensing oxygen, but don’t really know much beyond that.  Let’s break it down:  your vehicle has an oxygen sensor in the exhaust manifold that measures how much unburned oxygen there is in the exhaust.  The sensor reports its findings to the engine control unit (ECU), which knows how much oxygen there should be in the exhaust.  Based on that information, the ECU will adjust the amount of fuel it sends to the engine.

This feedback and adjustment loop continues non-stop.  The goal is to have the optimal air to fuel ratio for performance, efficiency, and to lower harmful emissions.

There is a second oxygen sensor located in the exhaust pipe behind the catalytic converter.  It too measures the amount of oxygen in the exhaust, after it has been treated by the catalytic converter.  As the measurement is reported back to the ECU, the computer compares the oxygen levels before and after the catalytic converter to determine if the converter is still functioning properly.

So, 4-cylinder vehicles have two oxygen sensors.  V-6 and V-8 engines have four sensors, two for each bank of cylinders.  As you can imagine, the oxygen sensor lives and functions in a pretty hot environment so they will wear out over time.  Substances in the exhaust can also damage them leading to failure.  Outside elements like water and road salt can corrode an oxygen sensor and when the sensor goes bad it needs to be replaced.

You may be interested to know that oxygen sensors are often replaced needlessly.  When the oxygen sensor returns a measurement that is out of the specified range, it may trigger a trouble code in the ECU and the check engine light is illuminated.  Inexperienced do-it-yourselfers or part store employees may misinterpret a trouble code that reports an out of range sensor reading.  That could mean that the sensor is bad, but it could also mean that the sensor is accurately reporting a condition caused by some other malfunction.  A skilled diagnostician can sort this out and will only replace the oxygen sensor when it has truly gone bad.

When you have a check engine light come on and stay on, it’s good advice to have it checked out by a qualified service technician at Express Car Care.  The cause may be minor or quite significant, so it’s best to play it safe and let the professionals check it out.

Essential Engine Maintenance Tips

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Essential Engine Maintenance TipsAs we all know, the engine is as important to a car as a heart is to a human body.  Therefore, it’s important to keep the engine finely tuned so you’ll have trouble free performance, as well as longevity.  Still, engine maintenance is one of the most neglected aspects of the overall maintenance of a vehicle.  Here are five essential engine maintenance tips that if you follow, you can not only keep up the performance of the engine, but you can also keep your pockets safe from costly engine repair bills.

  1. Regular Oil Change:  This is the most important and a must follow engine maintenance tip.  We should strictly follow the oil change schedule provided by the manufacturer in order to keep the lubrication level at its proper place.  The engine oil catches metal particles and dirt, and if not kept at the right levels and changed at the right time, it can negatively affect the life of the engine.
  2. Avoid Rough Driving:  We should avoid driving our vehicles roughly and should practice engine friendly driving habits, like using proper speed-gear combinations and avoid overheating the engine.
  3. Maintaining Fluid Level:  The cooling system maintains the engine temperature and keeps it safe from overheating.  Maintaining the proper fluid level in the cooling system is very important and should be checked and refilled on a regular basis.
  4. Listen to Your Vehicle:  Keep a close eye and ear on the performance of every component and as soon as you hear any unusual sound coming from the engine, have it inspected.  Even a faulty spark plug or a dirty air filter can prove harmful for an engine.  These parts should be repaired or replaced as soon as you suspect a problem in any one of them.
  5. Regular Service:  We should strictly follow the service schedule recommended by the manufacturer.  This service includes checking, repairing, cleaning, replacing many of the essential components of the engine.  By staying on top of these essential engine maintenance tips, we can improve the performance and increase the life of our vehicle’s engine.

Axles

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AxlesQuestion:
I hear a clunking sound from my front wheel when I make a turn.  What could be the problem?

Express Car Care Answer:  One possible cause of the problem is a worn axle.  Front-wheel drive vehicles have axles that transfer power from the transmission to your front wheels.  There is one for each front wheel.  These axles are called constant velocity axles or CV axles for short.  Rear-wheel drive vehicles have axles that are in back and run between the differential and the rear wheels.  Then there are all-wheel drive vehicles which have an axle at each wheel.

When a front CV axle goes bad, it will make a clunking noise as you make a slow turn.  When a rear axle goes bad, the clunking or moaning sound will be in the back.  No, there really isn’t any preventative maintenance you can have performed to make your axles last longer, but you can have them inspected from time to time to see if a problem such as a leaking seal or torn protective boot has arisen.  Sometimes finding the problem early will make the repair easier and less costly.

Of course, axles do wear out and need to be replaced.  This is dangerous and should not be put off by drivers, because a severely worn axle can seize up causing damage to your transmission or other components.  This could even lead to an accident for any driver who ignores a worn axle.

If you suspect an axle problem, have it looked at right away.  Ask your friendly and knowledgeable service adviser at Express Car Care if it’s time for your axle to be replaced.

Ball Joints

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Most drivers in Denver know that ball joints are an important part of the suspension system.  Visualize a ball attached to a spindle, with the ball enclosed in a cup.  This allows the joint to move in several directions, kind of like the way your hip works.

Most vehicles have two or four ball joints on the front, depending on the type of suspension system.  The joint allows the wheels to move up and down as the tires go over bumps, as well as allowing the wheels to turn as you steer.  The ball joints are continuously working and are subject to normal wear.  Most ball joints on modern vehicles are maintenance free, meaning they are sealed and cannot be lubricated.  Once the lubricant breaks down or leaks out due to a broken seal, the ball joint will wear more quickly.  Ball Joints

You may hear a clicking or popping sound from a corner of the vehicle when turning and /or going over bumps as a ball joint is failing.  Your steering may begin to feel sloppy or stiff, depending on how the joint is wearing.  You may even feel vibration in the steering wheel at highway speeds.  Unusual tire wear is also a sign of a problem.

It’s important to replace worn ball joints BEFORE they fail.  Once it fails, the joint may not be able to constrain the steering angle of a wheel, causing you to lose control.

Your owner’s manual calls for periodic suspension system inspections.  The ball joints are an important component that will be inspected for safe function.  We can check to see if you are due for a suspension system inspection or ask you service adviser for an inspection if you are experiencing any of the signs of ball joint wear.

 

Tracking True

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Tracking TrueWheel alignment is often overlooked by busy car owners until serious tire damage has been done.  One wheel can be knocked out of alignment from the others by hitting a curb or a pothole in the road.

The tires will wear out very quickly and will need to be replaced prematurely.  It could also lead to suspension damage.  Conversely, worn suspension or steering components can lead to alignment problems for motorists.

But the big issue for drivers is safety.  When your wheels are out of alignment, the vehicle will pull to one side, which could lead to an accident.  When you’re out of alignment, you should have it taken care of right away.

Signs of alignment problems are:  Your car pulls to one side.  Also, your steering wheel may not be centered when you’re going straight.  If you see the edges of one or more tires rapidly wearing down, your should have your service adviser look it over.

If you’ve been in an accident that involved a wheel, you should get your alignment checked.  A big jolt can seriously throw things out of alignment, but drivers also need to understand that a series of smaller ones can add up.  Worn steering or suspension components can also lead to alignment problems for drivers.  That’s why your vehicle manufacturer recommends periodic alignment checks.

If your owner’s manual doesn’t specify, once a year might be appropriate, or check with your service adviser.  He’ll be able to tell you if your vehicle requires a four wheel alignment or if it’s just the front wheels that can be aligned.

One thing is for sure, the cost of an alignment is cheaper than having to buy new tires because of neglect.

 

Thermostat

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ThermostatThe thermostat on your vehicle is an important part of your cooling system.  Your thermostat performs a similar function to the thermostat in your home.  At home, you set your thermostat to maintain a comfortable temperature range.  When your home gets too hot, the air conditioning kicks on and when it gets too cool, then the heater.

Now your engine also has an optimal temperature range:  warm enough to run efficiently, and not so hot as to cause engine damage.  Your vehicle’s thermostat is a valve between the engine and the radiator.  When you first start a cold engine, the valve (thermostat) is closed, allowing the coolant surrounding the engine to warm up to the proper operating temperature.  As the coolant gets hotter, the thermostat opens, allowing coolant to flow through to the radiator to be cooled.  The thermostat opens and closes to keep the engine within a certain temperature range.

Now thermostats are rated for a specific temperature depending on the engine – not a one size fits all proposition.  Thermostats are subject to normal wear.  Proper operation depends on a special wax that expands as it heats up, to open a spring-loaded valve.  A worn thermostat could stick in the open position causing the engine to run too cool.  This is inefficient and could hurt performance and fuel economy.  If a thermostat sticks in the closed position, the engine can quickly overheat, possibly causing damage.

There isn’t a specific maintenance routine for the thermostat, but maintaining your cooling system by changing your coolant/antifreeze on schedule will make sure the coolant has enough corrosion inhibitors to protect the thermostat and other vital system components.  Cooling system experts recommend replacing your thermostat when you do a coolant flush or exchange.  Also, thermostats usually wear out faster than your hoses, so if you need to replace worn hoses, replace the thermostat at the same time.

If your temperature warning light comes on, have your cooling system inspected right away.  This could be a thermostat problem.  The thermostat could also be the culprit if you aren’t getting hot air when you turn on your heater.

The thermostat is a relatively inexpensive part that stands guard between you and catastrophic engine damage.  Follow your owner’s manual instructions, or check with your service adviser to see if it’s time for a cooling system inspection or service.

Service Intervals

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Service IntervalsQuestion:
I’m really confused about auto service intervals for various items on my car.  Help!

Express Car Care Answer:  The simple answer for Denver drivers is to follow the vehicle’s recommended service intervals listed in your owner’s manual or in your service center’s database.  But the team at Express Car Care sympathizes with you because of the confusing intervals for modern vehicles.

The days of simple rules of thumb that applied to most vehicles are long gone.  For example, let’s look at an oil change:  manufacturers’ recommendations run anywhere from every 3,000 miles to 15,000 miles.  This big range comes from engine design and recommended types of oil – so drivers really do need to know and follow the recommendations for their specific vehicle.

Your owner’s service manual will have a schedule for both maintenance services and inspections.

Service items include:  Tire rotation, wheel balancing, oil change, coolant service, transmission service, brake system, power steering system, fuel system, differential service, and transfer case service.

Inspections will include:  Alignment check, air conditioning, brakes, suspension, axles, exhaust, tires, lights, emissions, belts and hoses, and steering.

It’s important to remember there is NO exception that would make it OK to extend an interval.  These intervals already assume the “best case” conditions for a safe margin of error.  However, you may live or drive in conditions that are harsher than average.  Your owner’s manual may have a modified schedule for “severe service” – things like extreme temperatures, towing, hauling heavy loads, short trips, or stop-and-go traffic.

Consult your owner’s manual or with your service adviser about your driving situation and adjust your service intervals accordingly.

 

Viva la Differential

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Viva la DifferentialWith front-wheel drive being so common these days, the differential is also being taken care of during a transmission service at Express Car Care, so most Denver drivers don’t even have to think about it.  And most rear-wheel drive differentials don’t need to be serviced for many miles, so it’s understandable why it’s not something on the top of drivers minds.  Because of this, it’s not uncommon for people not to know they have a differential, let alone know that it needs service.

To understand better what a differential does, think about a high school track.  There are lanes marked on the track.  For the long distance races, the starting lines are staggered.  The starting lines for the outside lanes are ahead of the starting lines for the inside lanes.  That’s to compensate for the longer length of the outside lanes.  Staggering the starting lines means that each runner has the same distance to run.

The differential compensates for the difference in speeds on drive wheels between the inside wheel and the outside wheel in a turn because they have to travel together through slightly different distances.

Differentials do a lot of work and require very heavy duty parts, and those parts need protection.  The differential fluid lubricates the gears in the differential and keeps them cool.  The fluid eventually gets dirty and worn down.  Some kinds of differentials require special additives that break down over time.  So follow recommended intervals for replacing your differential fluid.

Your helpful and knowledgeable pro at Express Car Care will drain the used fluid and check it out for metal bits, which could be a sign of excessive wear on the gears.  He’ll then replace the fluid and install the additives if necessary.

Four wheel drive vehicles need special attention to their differentials because they have a differential on both the front and rear axles that work at different times and sometimes under heavy loads – so they may need to be serviced at different intervals.  Your service adviser can look up the recommended service interval or you can check your owner’s manual.

 

Emergency Items for Your Vehicle

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Emergency Items for Your VehicleEmergencies you might encounter in your vehicle can range from a flat tire in downtown Denver to being stranded in a snowy ravine for three days.  So you may want to consider a basic car emergency kit to keep in your vehicle at all times and also a travel kit that’s tailored to a specific trip.

Your close-to-home kit should include some basic items to work on your car, plus all the items you would need to change a tire, and also gloves, a couple quarts of oil, some anti-freeze and water.  A can of tire inflator is a good temporary fix for minor flats.  You’ll also want to have jumper cables or a booster box, flares, a flashlight and some basic hand tools.

Now for your comfort and safety:  a first aid kit, drinkable water, high calorie food, ( like energy bars) blankets, toilet paper, cell phone, towel, hat and boots.  Keep some change for a pay phone, emergency cash and a credit card.  If you live in an area in Colorado with frequent severe weather or an area where you might experience extreme conditions, you may want to carry provisions for longer emergencies.

For trips away from Denver, consider the weather and geography as you assemble your emergency items for your vehicle.  You’ll need to have a source of light and heat and will want to provide protection against the elements as well as adequate food and water for every person in your vehicle.  Always tell someone where you are going and have a plan for checking in along the way.  Then if you run into trouble, you can be reported missing as soon as possible and rescuers will be able to narrow the search area.  The key to safe travel is to keep your vehicle properly maintained, plan ahead, and let others know your itinerary.

Gasoline Direct Injection

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Gasoline Direct InjectionQuestion:  My new car has a “GDI” engine.  What does that mean to me and other drivers with this new type of engine?

 Express Car Care Answer:  GDI stands for Gasoline Direct Injection, it’s a type of fuel injection system that is becoming very popular on modern engines.

Let’s talk about the two most common forms of fuel injection.  Port Fuel Injection has been common in vehicles for the last several decades.  With this type, there is a small port just outside the cylinder on the engine.

  • The fuel injector squirts a bit of gas into this area just before the intake valve opens.
  • When the valve opens, air enters the port and mixes with the gas and then flows passed the valve and into the engine.
  • The gas and air mixture is compressed by the piston.
  • The spark plug fires, igniting the gas which pushes against the piston, thus powering the engine.

With Gasoline Direct Injection the process is a bit different.

  • First, there is no port outside the cylinder.
  • When the intake valve opens, air is drawn into the cylinder.
  • The air is compressed by the piston.
  • At the correct time, the engine management computer signals the fuel injector to spray gasoline directly into the cylinder. Because of this it’s called Gas Direct Injection.
  • The pressurized gas and air are ignited by the spark plug, powering the engine.

So why the move to GDI?  Well, by injecting the gas directly into the engine, the management computer is able to time the injection event more precisely.  Also the gas sprayed directly into the engine cools the compressed air enough to allow for better combustion.  This adds up to more power for an engine.

These two types of fuel delivery systems call for different kinds of fuel injectors.  Port fuel injectors squirt their fuel at 40 to 65 pounds per square inch – that’s like the pressure in a bicycle tire.  GDI injectors operate at over 2,000 pounds per square inch.

Of course it’s always important to keep your fuel injectors clean – but it’s even more necessary for GDI injectors.  When they become contaminated, the performance ends.  Different cleaners and cleaning processes are required for GDI engines.  Intake valves get a fair amount of carbon build-up over time.  With port injection, some gasoline flows over the valve when it opens to let in the gas and air.  This has a cleaning effect – which doesn’t occur with GDI.  So pouring a bottle of fuel system cleaner in your gas tank won’t reach the backside of those intake valves.  A professional fuel system cleaning process needs to be done on the GDI engines in order to get them clean.

So, GDI will continue to become more prevalent in everything from compact cars to pick-up trucks.  Ask your Express Car Care service adviser if your vehicle could benefit from a fuel system cleaning.

Brakes Service

Oil Change

Suspension

Transmision Service

Engine Service

Auto Tips & Tricks