Express Car Care of Denver

"Denver's Best Auto Repair and Quick Lube"

Timing Chain

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All engines have either a timing belt or a timing chain to synchronize the opening and closing of the intake and exhaust valves.  This keeps the engine running smoothly and efficiently.  If the timing is off, it may not even run at all.  Timing belts need to be replaced on schedule.  A broken or slipping timing belt could cause extensive engine damage.

Timing chains are being used more and more in modern engines.  They are more durable and usually don’t have a recommended replacement interval.  However, timing chains and their associated components do wear out over time.  The tensioner and guide rails can wear out, which causes the timing chain to be loose.  A tooth on a cam sprocket could break allowing the timing chain to slip.  You don’t want to wait for a complete failure ( and possible extensive damage) so it’s important to watch for the signs of impending failure.

You may notice sluggish performance, reduced fuel economy or difficulty starting when the timing chain system is worn.  You could hear a variety of noises:  rattle, rumble, whine, buzz, or whir coming from the engine.  If you experience any of these things, bring it to our attention and we’ll look into it.  If you do require a timing chain replacement, we’ll also replace all the other system wear components such as the tension and guide rails.

Although the timing chain does not require maintenance as we usually think of it, it does require constant lubrication.  The engine does this normally as it runs.  However, a low oil level or using a poor quality oil will keep the timing chain from being properly lubricated.  A timing chain can last a long time with regular oil changes using quality oil.  Regular oil changes are an easy way to lengthen the life of your timing chain, I bet we can all manage that.

 

Radiator Fans

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Denver drivers who are old enough have probably heard the term “fan belt”.  Back in the day, the radiator fan in your vehicle was turned by a belt driven by the engine.  There are still belt driven fans, although most are now driven by the serpentine belt.  But most vehicles now have electric fans that draw fresh air across the radiator to cool it.

As coolant/antifreeze circulates in the cooling system, it captures heat from the engine and flows into the radiator.  Air cools the radiator and the coolant in it before it sends it back into the engine to pick up some more heat.  Now your engine has an ideal temperature range in which it is most efficient:  it shouldn’t be too hot or too cool.  The electric radiator fans help maintain the ideal temperature.

A switch mounted in a cooling system passage checks the temperature of the coolant.  If the coolant is at the low end of the range, the switch turns off the fan motor.  When the coolant rises to a certain temperature,  the switch turns on the fan.  When you are running the air conditioning, the radiator fan will likely be turned on as well to help reduce the extra engine heat created by the load placed on it by the air conditioner.

A lot of vehicles will actually have two radiator fans.  One, both or neither may be running at any given time depending on the conditions.  When you are cruising at highway speed, the air rushing over the radiator and around the engine will help control the heat.  By contrast, stop and go driving around town doesn’t generate much natural air flow so the radiator fans will be working hard.

Some drivers may hear the sound of the radiator fan running after turning the vehicle off. This keeps the engine from heating excessively after it has been run and shut off.

Both the radiator fan motors and the switch are wear items that will eventually fail.  If your temperature light comes on while driving, you have a cooling system problem.  Your knowledgeable Express Car Care service adviser can test your entire cooling system, including the radiator fans, to determine what is causing the indicator light.  Of course, servicing the cooling system as recommended will help extend the life of all the components.  Ask your Express Car Care service adviser if you are due for a cooling system service.

Fuel System

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I’d like to give our friends in Denver a quick overview of the fuel system.  It starts with the fuel pump.  The fuel pump is located inside the tank and pumps the fuel out to the engine.  Somewhere along the way is a fuel filter, it has the job of filtering out dirt before it gets to the engine.

Our focus is to discuss how to make the various components of your fuel system work well and last as long as possible.

Now the best thing you can do for your fuel pump is to use good quality fuel.  Top tier gas typically has fewer contaminants and more detergents to keep things clean.  Using good gas, or adding a fuel system cleaner to your tank, can prolong the life of your fuel pump.  Because the fuel pump lives inside your tank, it’s pretty expensive to replace, so helping it last as long as possible is a worthwhile goal.

The fuel filter catches dirt and contaminants.  When it’s clogged, your engine may not be able to get enough fuel and could start to sputter.  Many fuel filters have a bypass valve that allows unfiltered fuel past when the filter’s clogged.  This prevents your engine from dying while you’re driving, but it can’t protect your engine from dirty fuel.

Check your owner’s manual or talk with your service adviser at Express Car Care about when you should replace your fuel filter.  Fuel will cause gum and varnish to build up in the fuel intake system.  A professional fuel system cleaning will remove the gunk to keep fuel flowing freely and help prevent contamination from reaching your fuel injectors and your engine.

Fuel injectors squirt fuel into the engine and the fuel must be delivered in a precise amount, at a precise time, under exact pressure, in an exact pattern.  Pressure can range from 45 pounds per square inch to 45,000 pounds per square inch depending on the engine.  As you may guess, fuel injectors cost a lot to replace.  Allowing them to get gummed up will not only hurt your engine performance and fuel economy, it will also cause the injectors to wear out much more quickly than expected.

A professional fuel system cleaning will keep injectors clean and working correctly.  It’ll also clean deposits from the inside of the combustion chamber and off the intake valves, giving you optimum performance and mileage.

Check with your service adviser and see when he recommends you have a fuel system cleaning.

 

 

Question About Your Head Gasket

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Express Car Care Tech Question:
My name is Landon.  I bought a new minivan and it started smoking out of the tail pipe.  My service center said my head gasket went out.  What can I do to prevent this from happening again?

Express Car Care Answer:

The head gasket fits between the top of the engine and the cylinder head.  Its job is to seal that connection and keep oil and coolant circulating in the right parts of the engine.

When it leaks, oil can get in the coolant and vice versa.  Sometimes coolant or engine oil can get into the combustion chamber where it gets burned with the fuel, which is what makes all the smoke that Landon was talking about.

He said his van was new, so it’s likely that the head gasket failed because it was improperly installed, which is very rare.  Sometimes they just burn through.

Engine overheating is a leading cause for blown head gaskets.  Following the schedule for cooling system service is a great way for drivers to avoid overheating.

Replacing a head gasket is a fairly expensive repair at most auto service shops.  It’s definitely worth investing in regular cooling system maintenance at Express Car Care to avoid that pricey repair job.  Ask your friendly and knowledgeable service adviser if it’s time for a cooling system service.

Timing Chain

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As your engine runs, the intake valves need to open up to allow air into the engine.  They remain closed while the air and fuel is compressed and ignited, powering the piston.  Then the exhaust valves open to release the exhaust.  This all has to be timed very precisely.  It is the job of the timing belt or chain to make sure all of this is synced up properly.

Timing belts are made of a very tough compound that can last for a long time.  Timing chains are made of metal and last for a very long time as well.  If your vehicle has a timing belt, your vehicle’s owner’s manual has a schedule for replacing the belt.  If your vehicle has a timing chain, there may not be a specified schedule for replacing it, but that doesn’t mean that the timing chain system is indestructible and never needs attention.

For example, the chain runs on sprockets on the crankshaft and the camshafts.  A broken tooth on a sprocket can cause the chain to slip.  When timing is off, even a little, your engine won’t run at all and could even be severely damaged.  There is also a tensioner that keeps appropriate pressure on the timing chain.  This keeps the chain tight while allowing it to absorb pulsations from the engine.  The tensioner can wear out.  There are also guide rails that keep the chain on the proper path that can become worn.

The bottom line is that at some time, one or more of the timing chain system components will become worn to the point that they are no longer performing within specifications.  Your service adviser can help you with recommendations for when timing chain components should be replaced on your vehicle and for signs of timing chain system wear.

Since timing chains and dozens of other parts, are lubricated by engine oil, smart drivers stay on top of regular oil changes to prolong their life.  Always use a high quality oil filter and oil of the recommended type and grade.

Simple Answers: Water Pump

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The cooling system in an engine has five components:  the radiator, the radiator cap, the hoses, the thermostat and the water pump.  The water pump is literally the heart of the system.  Just as your own heart keeps your blood circulating through your body, the water pump keeps coolant circulating through your engine.

The water pump is driven by a belt, chain or gear and only operates while the engine is running.  It has a limited life span and sooner or later will have to be replaced.  You can check your owner’s manual to find out how long your water pump should last.  Some can fail at only 40,000 miles, but almost all of them fail by 100,000 miles.

Water pumps can fail in two ways; they can spring a leak or their bearings fail.  Leaks can come from a cracked pump but usually develop at the gasket where the pump attaches to the engine.

If you hear a low-pitched grinding sound coming from the water pump, it’s time for a new one.  If you see coolant leaking in the area near the pump, it needs to be replaced.  Also, coolant on the driveway could indicate water pump failure.  Many water pumps aren’t visible because they’re under a plastic cover, so you may have to take your vehicle to an auto repair shop to know for sure if the water pump has failed.

If your water pump is run by the timing belt, then it should be replaced when you replace the belt.  Most timing belts need to be replaced at around 60,000 to 90,000 miles.  The labor for replacing a timing belt is about the same for replacing a water pump, so it’s cost-effective to take care of them both at the same time.

Also, if your water pump develops a leak (if it’s powered by a timing belt), you have to replace the timing belt as well since contamination by coolant fluid damages the belt.  It just makes sense for drivers to replace both of these parts whenever either one needs it.

Replacing a water pump is a car care issue that almost all of us face eventually.  They don’t last forever.  On the other hand, we can extend the life of most of the components of our vehicle through preventative maintenance.  Just as exercise and diet keep our heart healthy, regular inspections and fluid changes will keep our vehicles healthy.

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.

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.

Broken Timing Belt

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Broken Timing BeltQuestion:

My friend had a broken timing belt and it was very expensive to repair his engine.  What can I do to avoid a broken timing belt?

Express Car Care Answer:

Well, a broken timing belt can lead to one of the most expensive engine repairs Denver drivers will ever face.  The good news is that replacing your timing belt on its recommended schedule can help avoid those problems.  Here’s a brief overview of what the timing belt does:  Air is drawn into the cylinder of the engine through the intake valves.  After the air and fuel mixture is burned, it’s pushed out through the exhaust valves.  The timing belt, which is driven by the engine, turns the camshafts, that control when the intake and exhaust valves open and close.  It is the opening and closing of the valves that takes place at exactly the right time for the engine to run properly.

Beyond that, on some vehicle engines, the valves actually extend into the combustion chamber far enough that they can be hit by the piston as it moves up and down in the cylinder.  When everything is timed just right – no problem.  When the timing is off, the piston will slam into the valves and cause big damage for drivers.

The timing belt makes sure everything is timed just right.  However, the belt does have a useful life.  Beyond that it can brake or slip – and that’s when the damage can be done.  If your vehicle has a timing belt (some have metal timing chains) it will have a recommended interval for replacing it.  Be sure to check your owner’s manual or with your Express Car Care service adviser to make sure you know when your timing belt needs to be replaced…there is a lot at stake.

Getting to the timing belt requires a lot of labor, so service costs are higher, but it is certainly less than repairing a damaged engine.  If your timing belt drives your water pump, change them both at the same time to save labor costs.  Ask your Express Car Care service adviser when your timing belt should be changed and get an estimate for what it will cost, so you can budget for this service.

Alternator Replacement

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Alternator ReplacementSome drivers have probably noticed a bunch of warning lights on their dash when they start their engine.  They flash on to test the circuits and then go off if everything’s OK.  One of the warning lights looks like a car battery.  Its job is to tell you if your vehicle’s battery isn’t charging properly.

Most motorists probably know that their battery stores electricity – enough to start the engine and get moving.  but that’s about it – you can only get a few miles on battery power alone.  You need an alternator to generate enough electricity to run your vehicle’s engine and power your electrical accessories, like the stereo, power seats, heater fan, on-board computers, and so on.  On top of that, the alternator needs to recharge your battery.  So when your alternator isn’t working, there isn’t going to be enough electricity for all of those things.  When your alternator fails, you aren’t going very far.

So why would your alternator not work?  Usually they’ve simple worn out.  Alternators are driven by your serpentine belt and spin 2 to 3 times faster than the engine – that’s a lot of work.  The bearings wear out, as do the copper wire coils and magnets that generate the electricity.

There’s no sense in hobbling along with an alternator that’s not working properly.  It will fail at some point and leave you stranded, then you’ll be wishing you would’ve had an alternator replacement sooner.  You need to get a bad alternator replaced as soon as you possible.  When you come to Express Car Care for an alternator replacement, someone knowledgeable will install an alternator that meets your specifications.  Some drivers use a lot of additional electrical products in their vehicles, like computers and DVD players.  Others may regularly tow a camping trailer that is putting extra pressure on its battery as they drive.  If that sounds like you, you’ll need to think about upgrading to a more heavy duty alternator.  Come in and let us help you figure it out.

Brakes Service

Oil Change

Suspension

Transmision Service

Engine Service

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