AUTONET TV

Plugging Away (Spark Plug Replacement)

If you drive a vehicle with a gasoline engine, thank the spark plugs for igniting the gasoline/air mixture in each cylinder that keeps your vehicle traveling smoothly down the road every day.  Your spark plugs work hard, firing thousands of times in a well-choreographed order, and you usually don't pay much attention to them until one of them stops working the way it should.

Signs that spark plugs are wearing out include:

• Engine runs more roughly than it did
• Vehicle doesn't start as easily as it used to
• Vehicle hesitates when you press on the accelerator
• Your fuel economy has gotten worse

When a spark plug stops working altogether, you will find your engine has likely lost a lot of its power and isn't running smoothly.  Your Check Engine light may  come on.  Then it's time to head to come to our service center to have it diagnosed.

If your plugs need to be replaced, they're usually done all at the same time. And if your vehicle has spark plug wires, experts recommend you change them as well. Different type of spark plugs last longer than others, and your service advisor can discuss what's best for your vehicle and driving habits.

A technician will also determine if there are any carbon deposits on your plugs, how healthy the ignition coil is (it's the part that supplies the high-voltage jolt that makes the spark) and will look for other signs and symptoms that may point to other problems in your engine. For instance, if a spark plug is fouled by oily deposits, it's possible oil is getting into the combustion chamber. 

They will also check all the plugs to see if there are problems in just one or all cylinders.  Sometimes a technician will find a plug that has overheated, literally melting the metal.  In that case, they may recommend they correct that problem before replacing the spark plugs.

Most spark plugs will last for a good, long time.  Even if you aren't seeing any symptoms they're wearing out, make sure you have your service advisor check your vehicle manufacturer's recommended maintenance intervals.  Preventative maintenance will keep your vehicle running reliably so you can count on it to get you where you want to go. 

McLearen Shell
3043 Centreville Road
Herndon, VA 20171
(703) 318-7744
http://www.mclearenshell.com

Drive Train Service in Herndon at McLearen Shell

The drive train in your vehicle includes all the components that transfer power from the transmission to the wheels. Those components differ depending on what type of vehicle you drive, namely, front-wheel drive, rear-wheel drive, all-wheel drive or four-wheel drive. The preventive maintenance your driveshaft needs will also differ by what type of vehicle you drive.

Let's start with front-wheel drive. In this vehicle, the transmission and the differential are combined in one component, known as the transaxle. The transaxle is connected to two half-shafts (axles), which are then connected to the wheels with a constant velocity (or CV) joint, which is protected by an airtight rubber boot.

McLearen Shell service for this type of driveline includes servicing the transaxle and inspecting the CV boot. If the boot is damaged, the CV joint will need to be inspected, and the boot will need to be replaced. If you hear a clicking noise in your wheel wells when you turn, you may have a damaged CV joint. A damaged CV joint should be replaced.

Rear-wheel drive vehicles generally have a transmission in the front of the car and the differential in the back. A driveshaft (it looks like a long tube) connects the transmission to the differential. Some vehicles may have a two-piece driveshaft, which are connected to the differential with universal joints or U-joints. Again, the differential is connected to two half-shafts that go out to the wheels.

McLearen Shell service on the drive train on a rear-wheel drive vehicle starts with servicing the differential. It will need its fluid drained and replaced regularly. The seals on the axles should also be inspected for wear or leaks. Leaking or damaged seals may mean the axle needs to be serviced as well. Also, U-joints can wear out. If you hear clunking or feel a jolt when you shift into drive or into reverse, it could indicate a driveline problem.

All-wheel drive vehicles provide power from the transmission to all of the wheels, instead of just to the front or rear. The advantage is that the vehicle can adapt to different driving conditions and transfer more power to the front or back wheels as needed. The disadvantages are that the driveline is more complicated, and the vehicle weighs slightly more.

Many all-wheel drive vehicles are based on a front-wheel drive set-up. They also have a differential in the rear and one in the center of the vehicle that allows power to transfer to the front and rear. A shaft runs from the transfer case to the center differential, and another from the center differential to the rear differential.

Servicing an all-wheel drive at McLearen Shell involves servicing ALL of the differentials and inspecting the joints and seals for wear, leaks or damage.

Four-wheel drive vehicles are rear-wheel drive vehicles that have an option to transfer power to the front wheels. In other words, they can be driven as either rear-wheel or four-wheel drive vehicles. These vehicles are specifically designed for the harsh driving conditions Herndon drivers encounter off-road. The driveline in a four-wheel drive vehicle is similar to that of an all-wheel drive vehicle. The center differential, however, is a transfer case. Maintenance requires servicing both of the differentials and the transfer case, as well as an inspection of the joints and seals.

Herndon auto owners would be wise to check with their owner's manual for recommendations on how often to service their vehicle drive train. It's also good auto advice to check with your friendly and knowledgeable McLearen Shell service advisor as well. You may live in an area in VA where weather or driving conditions require more frequent servicing of the drive train.


Good car care at McLearen Shell in Herndon always includes taking care of your driveline. Without it, your vehicle becomes a very large paperweight.

McLearen Shell
3043 Centreville Road
Herndon, VA 20171
(703) 318-7744
http://www.mclearenshell.com

Stuck! (Vehicle Door Issues)

This may have happened to you.  You drive somewhere and get out of your vehicle only to try closing the door and it just won't stay closed!  What a helpless feeling.  You can't lock it; you can't leave it like it is. Or, let's say you head down to your vehicle to head out to work in the morning and you can't open the door.  What are you going to do now?

Vehicle doors take a lot of abuse.  They are opened and closed hundreds of times and we expect them to just keep working perfectly all the time.  They do require a bit of tender loving care.  Let's take a look at two different scenarios of stuck doors.

First: the door that won't close.  It's a security issue.  It's also a safety issue.  You can't really safely drive a vehicle with a door that won't close. What if you or a passenger is tossed out?  Sure, some people try to tie a stuck-open door closed or bungee it, but that's dangerous.  It's best to get that vehicle to the service repair facility as soon as you can, and having it towed is the safest way. 

Second: the door that won't open.  There are many reasons this can happen.  Freezing weather is one, a misaligned door is another.  There could be electrical issues.  Corrosion could have broken a part inside the door.  The possibilities, unfortunately, are numerous.

If you can't get into your vehicle's driver's door, with any luck another door might open and you can climb into the driver's seat and head on to the repair facility.  A lot of people may be tempted to try to fix a stuck door themselves, but many wind up causing more damage to the door and have to have a trained technician step in to repair the mess.

One way to minimize the possibility of having a door stick open or closed is to make sure it gets regular maintenance.  Door locks, hinges and latches should be lubricated at certain intervals.  Locks should be kept clean.  While many vehicles now have electronic locks, sometimes an electrical failure in the vehicle or key fob can inadvertently lock you out.  Nearly every vehicle has a mechanical key in case that happens; if you don't know how that works, have your service advisor show you how. 

Also, you technician can make sure your doors are properly aligned and aren't sagging. All of these things can help you keep your doors opening and closing the way they were designed to. Your next trip may "hinge" on your doors being in top condition.

McLearen Shell
3043 Centreville Road
Herndon, VA 20171
(703) 318-7744
http://www.mclearenshell.com

Differential Service at McLearen Shell: Viva la Difference

Every vehicle on VA roads has a differential, and it is important to the proper operation of the vehicle.  But most Herndon residents don't have a clue what it is.

The differential compensates for differing wheel speeds. For example, when you turn, the inside tire on the turn travels a much shorter distance than the outside wheel. So the inside wheel of the vehicle must move at a slower speed than the outside wheel. Without a differential, the wheels would hop and scrape while turning.

Have you ever seen the large bulge in the middle of the rear axle of a truck? That's the differential. In a rear-wheel drive vehicle, the differential is located on the back axle. Four-wheel drive vehicles and SUV's have differentials on both the front and the rear axle.

You might expect that the differential is located on the front axle of a front-wheel drive vehicle. You'd be right. But the differential is called a transaxle on a front-wheel drive vehicle because its location allows it to be combined with the transmission.

In an all-wheel drive vehicle, an additional differential or transfer case is located between the front and rear axles. Differentials are strong: They have to be because of the job they do. But those tough parts need proper lubrication. You don't want your differential to seize up. That results in damage to your vehicle.

So you need to have your vehicle differential serviced regularly. It's not a complicated job. At McLearen Shell in Herndon, we've been servicing differentials for years. The used lubricating fluid is simply drained and then replaced. Some vehicles require specific additives in the differential fluid; your Herndon service center will ensure you are getting what your vehicle needs.

The intervals in time or mileage for servicing your differential vary greatly from vehicle to vehicle. Check with your owner's manual or McLearen Shell service advisor to find out how often your vehicle differential needs to be serviced.

McLearen Shell
3043 Centreville Road
Herndon, VA 20171
(703) 318-7744
http://www.mclearenshell.com