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