Rockville Auto Repair

You've probably never paid much attention to the writing on the sides of your tires, but they contain a wealth of information.  There's a long combination of letters and numbers that can tell you a whole lot about what tires your vehicle was designed to be riding on.  Let's check out this example found on an SUV: P245/70R17 108T. The first letter, P, means it's intended for passenger vehicles.  If there's no letter, it means it's a metric tire.  If there's an LT at the beginning or end that means a tire designed for light trucks. Moving on to our example, the 245 shows how wide the tire is in millimeters from sidewall to sidewall.  The number that follows in our example, 70, means the height of the tire is 70% of its width.  The letter after that in our example, R, describes the type of tire (on this vehicle, radial).  Following that is the diameter in inches, in our SUV example, 17 inches.  How much load the tires' sidewalls are designed to take ... read more

If you’ve noticed your vehicle is hard to start, stalling, or has lost power, the culprit may be a part with an odd name: the MAF sensor.  You may have never even heard of a MAF sensor, but it’s important that it be working correctly, or you may be experiencing some fairly significant engine issues. All vehicles bring in air and direct it through an air filter before it goes into your engine, where it mixes with fuel to provide power to get you going. There’s a tube-like device with a sensor inside it that measures how much of that mass of air is passing through. That’s why it’s called a mass air flow sensor, or MAF sensor.  If the MAF sensor isn’t working right, the engine’s computer can’t figure out the right amount of fuel to mix with it, and your engine may hesitate or stall.  Sometimes this will cause your Check Engine Light to come on, and any time it does that, make sure you have your vehicle checked by a professiona ... read more

If you've ever ridden down a rough road on your bicycle, you know how hard a ride it can be.  Yet drive down the same road in your car, truck or SUV and it miraculously will smooth out the ride.  That's because it is equipped with shock absorbers.  They are built to dampen impacts from road irregularities.  But after taking hundreds of hits from potholes, railroad tracks and curbs, your shock absorbers can wear out.  Besides the rough ride that can cause, there are other ways your vehicle's performance can be affected. When it comes to braking for example, you may take a longer distance to stop.  That's because shocks help keep your tires in contact with the surface of the road.  If the shocks aren't working properly, the tires won't make contact like they should.  So when you slam on the brakes, your vehicle will take longer to stop. Consider what worn out shocks are doing to your tires.  Since the bumps aren't being dampened as much, your ... read more

There's nothing quite like getting in your vehicle on a hot day, switching on the air conditioning and having warm air blow out of the vents.  You may have had no problem for months and then, one day, you are driving around in a sauna. You're hot stuff, but not in a good way! So what goes wrong when the AC isn't working? It could be a lot of things because the system has many different components.  One thing that's a common cause is the vehicle is low on refrigerant (it used to be called Freon).  If that's the case, it's not as simple as simply adding more.  Sure, it may fix it quickly for a short time, but it's more likely than not that the refrigerant will just leak out again. The original Freon used in air conditioners was destroying the Earth's ozone layer, so that's not used much any more.  But the one that's currently used also contributes to global warming, so it's important that as little of that escapes as possible.  So a technician will determine ... read more

Driving along, your exhaust system's rumbling so loud that people turn and stare at you pass by.  You're wondering when the police are going to pull you over for illegal noise. Your mind immediately thinks, aha! A broken muffler.  Well, your exhaust system is composed of many more parts than just a muffler.  Your engine makes power because of thousands of tiny explosions from detonating fuel.  Those explosions make a racket, so engineers came up with a system that acoustically dampens that sound in addition to getting rid of harmful exhaust. In the engine is the exhaust manifold that looks like several pipes that join up into one pipe.  It directs exhaust to the catalytic converter. The catalytic converter converts harmful gases into less harmful gases using certain chemical reactions.  Then comes the muffler that has baffles inside to quiet the sounds of your engine noise.  Finally: the tailpipe. All of those pipes and parts are joined together by cl ... read more

Your vehicle may be like that famous battery bunny, the one that just keeps going and going.  But while it may seem sometimes like you never need to take your vehicle in to be worked on, there are some things you should keep your eyes, ears and nose out for. They are warning you about something that needs attention at your vehicle service facility. If a warning light is on, don't ignore it; do something about it.  There are warning lights for battery, oil, engine heat, tire pressure… you name it.  And the manufacturer put them there for a reason.  They're telling you something isn't normal. So when one goes on, have it checked out soon, especially the blinking Check Engine light.  The earlier you have any warning light issue diagnosed, the more likely you are to avoid a more serious problem. If your vehicle is vibrating or shaking, it's not only annoying, it could signal trouble.  You can bet your vehicle didn't do that when it came out of the fact ... read more

Can you think of anyone who likes getting a flat tire?  Of course not.  But when one of your tires winds up with a flat or leak, whether it be from things like hitting a curb, running over a nail or picking up a sharp stone, it's time to have someone who knows what they're doing take care of it. If you're thinking you'd like to avoid having to buy a new tire, you wonder if a patch or plug will suffice.  It depends where the puncture is and how big the hole is.  Most tire experts will say if the hole in the tire is less than ¼ of an inch or 6 mm, a patch can work.  But a patch likely won't work if the compromised part of the tire is on its shoulder or sidewall. Here's why.  The shoulder of a tire is the part between the sidewall and tread and it's usually rounded.  It's under a lot of pressure, more than even the sidewalls. And because of that curved shape, it's hard to get a patch or plug to hold. The sidewall is the side of the tire.  Sid ... read more

You may have noticed your vehicle going through lean times.  By that, we mean it's literally leaning to one side.  When you notice that, you should get it checked out at your service facility soon because you could have a serious problem. Many things can cause a vehicle to lean.  You may have problems with your struts, shocks or springs.  They all work in tandem to make your ride more comfortable.  The struts bear the weight of the vehicle's body, the shock absorbers employ a piston that keeps your tires in contact with the road and controls movement of the vehicle's body.  Springs also absorb impacts from uneven road surfaces. If these components get stuck, either too high or too low, they cause your vehicle to lean.  That's because that side of the vehicle isn't at the height it is designed to be.  A technician will determine where the problem is.  Outside elements such as moisture plus hard knocks to these components can weaken them, even ... read more

You’ve probably already heard that regular oil changes are extremely important for the health of your vehicle’s engine. That’s sound advice.  But what you might not know is when it comes to motor oil, the real thing may not be the best thing for your engine. There are different types of motor oil: Conventional oil, extracted from the ground and refined. Synthetic oil, manufactured from high-quality base oils and artificially-made chemical compounds. Synthetic oil blend, a mixture of conventional and synthetic oils. The first thing you need to know is that most new engines require synthetic oil.  If synthetic oil is recommended for your car – you MUST use it. For the rest, there are many advantages to using synthetic oil over conventional oil. Synthetic oil provides better protection for your engine while helping it to perform better. Conventional oil breaks down over time, while synthetic oil lasts longer. Synthetics can stand higher temperature ext ... read more

When the leaves fall, you might take a sightseeing trip to see them at peak color.  Or you may simply live in a spot where there are a lot of trees.  When those leaves get wet, you'd be surprised to learn just how slippery they can be.  We all know ice is slippery to drive on.  What causes tires to slip on ice is a thin layer of water that comes between the road and your tires.  Wet leaves can have the same effect.  The surfaces of leaves are super slick when they're dry, even worse when you add a little moisture.  There's one other thing about leaves.  They are smaller than each tire's footprint, so your tread grips the pavement with uneven traction. One study showed that your stopping distance can more than double on a surface covered with wet leaves when compared to that same road when it's dry.  Double! That can spell trouble.  So if you find yourself heading into an area with wet leaves on the road, slow down before you get into a ... read more