Rockville Auto Repair

It's easy to get letters like PVC and PCV mixed up.  PVC is a plastic that's used in a lot of things, especially plumbing pipes.  And PCV is a valve that helps your engine burn off excess fumes rather than having them pollute our atmosphere.  PCV stands for positive crankcase ventilation.  When your engine ignites gasoline in the cylinders, some of the gases produced make their way into the crankcase, where oil is held to lubricate the engine.  In earlier days, those gases would be vented out through a hose and go directly into the air.  It was a waste of gasoline (since about three-fourths of the gases were unburned fuel) and a nasty source of pollution. So engineers devised a one-way valve that directed those gases back into the engine's air intake system to be burned again.  After a while, the PCV valve can get clogged up with gummy oil.  Not only does that reduce the recirculation of the gases, but it can also cause pressure in the crankcase ... read more

When you're driving and turn a corner, you probably aren't aware of all that's going on with your wheels.  The outside wheels have a longer distance to travel than the inside wheels, so there are gears that allow the wheels to go at different speeds when you turn.  That set of gears is called a differential.  In front-wheel drive vehicles, it's by the transmission and called a transaxle.  Rear-wheel drive vehicles have the differential, naturally, on the rear axle. Many all-wheel and four-wheel drives add a center differential since power has to go to the front and rear wheels. (Some newer vehicles power wheels with electric motors, but that's a whole different story.) Time and distance traveled eventually can take their toll on the differential, and you may notice some noises you hadn't heard when your vehicle was newer.  Sometimes you'll hear a whir that might change in pitch when you turn.  You may hear clicking sounds when you're moving.  Others d ... read more

Seems like these days, we're hearing about more and more electric or hybrid vehicles.  Keep in mind that conventional gasoline internal combustion vehicles have important electrical components, too, and it's important to make sure they're operating at their peak. In a vehicle with a gasoline engine, the part that keeps the battery charged is the alternator.  It converts the mechanical energy created by the engine into electrical power.  To do that, a shaft in the alternator has a pulley on one end that's driven by a belt that is turned by the engine.  A series of magnets then spins around coiled wires and it creates alternating current, or electricity. Your vehicle uses that to charge the battery that, in turn, keeps other electrical components in your vehicle working. Here are a few signs that the alternator isn't doing its job right.  The battery keeps going dead, your instrument panel's battery light is on (it looks like a rectangle with a - and + inside and ... read more

Ever wonder how your vehicle’s transmission is connected to your wheels? After all, when you hit a pothole or some other uneven part of a road’s surface, there has to be something that can maintain the connection between the transmission and the wheel yet keep everything moving at the same speed.  That very cool device is called a CV joint, a kind of driveshaft running to each wheel.  The CV stands for constant velocity because it keeps the drive wheels moving at a constant speed (velocity).  They’re used mostly on front-wheel drive vehicles but also in rear-wheel and all-wheel drive vehicles. The joints move up and down and adjust to bumpy surfaces.  Plus, they are covered in a rubber boot which protects them from road debris and also holds lubrication in.  There’s a CV joint and boot on the transmission side and one on the wheel side.  Unfortunately, the spot that usually fails first is that rubber protective cover (the boot).&nbs ... read more

You know how exposing your skin to sunlight can cause sunburn and other unhealthy things.  Sunlight can also create major problems for your headlights.  After they've been exposed to ultraviolet light, acrylic headlights can yellow and fog due to oxidation.  And when that happens, less light can pass through the plastic, reducing the effectiveness—and safety—of your headlights.  It's not just the UV light that causes headlights to turn cloudy.  Road grime and debris gets kicked up and can scratch the plastic, diffusing the light that should pass through them when they're clear.  Plus, when your vehicle was new from the factory, the headlights had watertight seals all around to prevent moisture from getting into them and fogging them up with water vapor.  Just like clouds can hide the sun, tiny water molecules can diffuse the light from your headlight bulbs.  Sure, you could buy replacement parts and start fresh.  But the good new ... read more

With hotter weather and brutal heat waves becoming more common, the pressure in your vehicle's tires goes up.  After all, heat causes air to expand, and the air in your tires follows the laws of physics. Overinflated tires can reduce your vehicle's traction, cause a hard, punishing ride and make your tires wear out faster; all are important safety issues. Four out of every ten drivers rarely check tire pressure. Some rely on their vehicle's tire pressure monitoring system (TPMS) to keep an eye on proper tire inflation.  But it's not designed to do that. TPMS is a safety feature that has been required on vehicles made in 2008 or later, using sensors in the wheels that alert you to tire pressure problems.  That warning can be a light on your dash, a digital message or a readout of the pressure in each individual wheel.  But a study showed that more than 40 percent of drivers don't even know what the tire pressure monitoring light symbol looks like! One looks like a ho ... read more

You're heading down the road and you notice your vehicle is sputtering, like it's running out of gas.  But the gauge show's it's still got a quarter of a tank.  So what gives? It could be that your fuel pump is failing, meaning your engine is not getting enough gas to run properly.  While fuel pumps are built to last a long time, sometimes they fail.  Other symptoms you may have a bad fuel pump include your vehicle stalling and then refusing to start again, the engine overheating or a hum or whirr coming from around the gas tank.  Or, your Check Engine light may come on. Most fuel pumps are in the gas tank. They have a small electric motor in them.   When you bring your vehicle to our service center, a technician will run tests to confirm the fuel pump is getting power to it but has failed.  Some vehicles have an access panel so the fuel pump can be removed and replaced.  But in some vehicles that don't have that access panel, the technician ... read more

Your vehicle's brakes wear out.  It's inevitable. You'll notice it when you step on the brake pedal and feel it harder to stop, or there's vibration when you are braking.  Most modern vehicles have disc brakes that each use a brake pad that press on a disc (disc brakes!) called a rotor.  The friction between them enables you to stop, and each time you do a little bit of the pad and the rotor wears down. The original brakes on vehicles used a rotor that was thick enough to last through at least two replacements of the pads.  But vehicle manufacturers who want to save costs and weight now make them thinner, and sometimes the rotors have to be replaced after the first pad replacement.  But not always. Vehicle manufacturers specify a minimum thickness to provide safe braking.  Sometimes rather than having to have your rotors replaced, they can be put on a lathe and resurfaced.  In other words, the surfaces of the disc can be slightly shaved off so the sur ... read more

When it comes to oil changes, things are really changing.  Most newer vehicles require synthetic oil, and while it costs more than conventional oil, it doesn't need to be changed as often. When conventional oil was the only game in town, you changed your oil every 3,000 miles/5,000 km. But as technology in newer vehicles has rapidly changed, so has oil technology.  Synthetics have been around since the seventies.  Even though they start with a conventional oil base, they are engineered in a chemical processing plant with properties that allow them to keep your engine lubricated at very high temperatures.  They are more uniform and consistent. Synthetic oil doesn't break down as easily, so it lasts longer than conventional oil.  And synthetic oil can flow more easily, even in extremely low temperatures.  As you can see, it has performance advantages at both temperature extremes. Generally, in recent years automakers have been shipping most of their vehicles ... read more

Maybe you've been cooped up for a while and are yearning for a change of scenery.  Or maybe you need to visit a relative who lives far away.  You choose not to fork out the big bucks for airline tickets, so it's time for a road trip.  Make sure you're road ready by having your vehicle professionally inspected before the big drive. One of our technicians can check out several of your vehicle's most important systems so you can be more confident that you'll be able to go the distance without a breakdown.  Here are a few things a trip inspection may include: Your vehicle stops with brakes that, in turn, stop the tires.  They must both be in sound condition. The technician can look at your tire tread, the condition of the sidewalls, and note the tires' age.  Brakes have pads and rotors that should meet certain specs, so an expert inspection of their condition is important, too. A technician can check other vital fluids such as engine coolant, power steering, t ... read more