Rockville Auto Repair

Your gasoline engine goes through some exhausting work.  Yes, it's truly exhausting, as in: it produces exhaust! And when your engine starts behaving like it's exhausted, such as running poorly or getting lousy fuel economy, the trouble may be something called a PCV valve. Did you know it's a series of explosions that creates the power in your engine? The spark plugs ignite a mixture of gasoline and air and BANG! A whole bunch of those and you're engine is humming away. Leftover vapors from those explosions go into your crankcase, which is also a place where engine oil goes.  Those vapors still have a lot of unburned fuel in them, and if they had nowhere to go, they'd turn your oil into a thick mess called sludge, not good for a smooth running engine.  Engineers came up with an idea. Re-direct those gasses building up in the crankcase into the engine's air intake and mix them with fresh air.  That way the unburned fuel could go through the engine again and produce p ... read more

You probably figured out those shifty letters.  They're what you see on your automatic transmission shifter and stand for Park, Reverse, Neutral, Drive and Low.  Your automatic transmission is one of the great automotive inventions; here are some ways you can keep yours working well. Maintain your transmission regularly.  A technician will check your transmission fluid's level and even its appearance and smell.  If it's dark or has an unusual odor, that could be a sign of trouble. Change from one transmission direction gear into another only when your vehicle is stopped.  So many drivers want to switch from Reverse to Drive quickly or the other way around.  If you do that when the vehicle is moving, you can damage your automatic transmission. Keep your vehicle's cooling system in top shape.  What does the cooling system have to do with the transmission? It helps keep the transmission fluid from overheating.  Follow the manufacturer's recommendati ... read more

In warm weather, you want to be in a cool vehicle. When we're talking cool, we don't mean stylish or trendy, but cool as in not sweltering inside.  And if your vehicle's air conditioner stops working correctly, it seems to always break at the worst time—during a heat wave.  Automotive air conditioning problems fail for a number of reasons: Blower motor not working.  No air comes through the vents, even though the rest of the system could be working fine. Refrigerant leak. When the gas that cools the air off escapes from the air conditioning system, your air conditioner can no longer cool off the outside air Condenser and compressor. These are parts of your AC system that compress and expand a refrigerant gas to cool off the outside air. They are fairly complex. When you bring your vehicle into our service center, we'll run a series of diagnostic tests to figure out what isn't working correctly.  The air conditioning system has a lot of parts. There are elect ... read more

A driver brought her vehicle into the shop the other day and told us how she was getting lousy fuel economy and that the engine was running rough.  Plus, the Check Engine light was on.  Our technician checked the code the engine had generated (why the Check Engine light was on) and found the problem.  It was a faulty Mass Air Flow sensor, MAF sensor for short. This MAF sensor is an important part of your vehicle.  What it does is calculate the amount of air going into your engine.  As you may know, air is taken into your engine where it's mixed with fuel.  Then, the spark plugs fire, that explosive fuel/air mixture detonates, and all these sequential explosions together provide the power to get your vehicle moving down the road.  It makes sense that if the MAF sensor isn't sending the engine's computers the correct information on the amount of air going in the engine, the fuel/air mixture isn't going to be right. It will either too rich (too much gaso ... read more

Your vehicle is loaded with electrical devices. Computerized components are everywhere, so good electrical connections are important.  Those begin with your vehicle's battery, so it's important that its connections are in top shape. Ever had a flashlight that didn't work, took out the old batteries to replace them and noticed the old batteries were all corroded? The same thing can happen to your vehicle's battery.  The battery type used in most vehicles is a lead-acid, which can be very corrosive.  Corrosion can build up around your battery's terminals that can prevent the electrical connection from being as solid as it needs to be.  You may have even seen discoloration around your battery's terminals if you look under the hood, a sign of corrosion. Or you might notice visible signs of fraying or loose battery cables. All of your vehicle's components are affected by vibrations from the engine and road surface imperfections, and the battery cables take a lot of jostl ... read more

You know that sinking feeling when you realize one of your tires has a problem.  It may be making an odd noise or behaving oddly when you're driving.  You may hit a pothole or curb and one suddenly goes flat.  Or you may head back to your vehicle and discover it has one tire deflated without a clue of what must have happened to it. With a lot of different tires hitting the streets these days, the issue of whether to have a tire repaired or replaced can be tricky, and we strongly recommend you have a trained technician help you make that decision.  One of the most common causes of flat tires is picking up a screw or nail in the tread area.  Many of those can be patched and plugged if the puncture isn't more than ¼ inch/6 mm in diameter. Most tires can handle two of this type of repair, but any more and you should buy a new tire.  If there's a puncture or bulge in the sidewall or shoulder, the rule of thumb is it's not repairable.  The sidewall d ... read more

When you hear hissing sounds coming from your vehicle, you might start thinking the worst.   One type of hissing coming from around your air conditioner may be a normal sound, or it could be a sign of serious trouble. First - the normal sound.  When you turn off your vehicle, the refrigerant goes from its high-pressure side to the low-pressure side. Some of those noises are normal.  But when it hisses all the time, that's another story. One cause could be that the refrigerant is leaking.  Air conditioners are fairly complex systems that involve various pumps, hoses, valves and motors.  When your air conditioner is cooling, the refrigerant changes from a gas to a liquid and back.  That refrigerant is under pressure, and there are many places it can leak from.  A hissing sound can also be a failed valve in your air conditioner's compressor.  It is what controls the refrigerant's pressurization.  It's important to have this fixed fairly qu ... read more

Air conditioning used to be a real luxury in a vehicle, but now it's standard in most.  Your vehicle's air conditioning system is built to last a pretty long time, but like anything mechanical, sometimes it fails.  It helps to know a little about how the A/C works. There's a compressor that pressurizes the refrigerant (you probably recognize the term Freon).  That makes it hotter, so it then goes through a condenser that cools it off.  Then another component takes out impurities and humidity before the Freon goes to a device that makes it lose pressure before it goes to the evaporator.  That's where it gets colder and takes the humidity out of the air. Then your vehicle's ventilation system blows air over the evaporator, cooling the cabin air that gives you such relief on a hot day. Of all these parts, one that does a lot of work is the compressor.  It has to compress that refrigerant and circulate it through the system.  It turns on and off several t ... read more

One of the most important things you can do to keep your vehicle running safely is to make sure your tires are properly inflated.  If one or more is vastly over- or underinflated, that has the potential to cause major handling problems and may result in a dangerous accident. All vehicles in recent years are equipped with Tire Pressure Monitoring Systems, or TPMS.  One system uses small sensors in the tires that continually check the pressure in each tire.  That sensor sends a signal to computers in your vehicle which turns on an instrument panel light warning of low pressure when at least one is very low. Or it may update a numeric reading on your instrument panel which gives you an approximation of how many PSI (pounds per square inch) of air is in each tire.  Another system works with your antilock brake system to measure the size of your vehicle’s tires.  When one wheel is going faster than another, it will spin faster. A computer sees that and alerts ... read more

Most of us know a bad muffler when we hear it.  That loud, rumbling sound is unmistakable. Did you also know you can get a ticket for driving around with a loud exhaust system? If your exhaust system has a leak in it, it may be allowing poisonous gases inside your vehicle and could make you seriously ill (or even kill you!) if you breathe too much in. Unfortunately, your exhaust system faces a lot of destructive forces out on the road.  Rust is the worst, and not just in colder climates where they use salt and brine as de-icers.  Exhaust systems can rust from the inside out when moisture condenses inside the pipes.  Vibrations and jolts from rough roads (and the occasional run in with a rock or a curb) can wreak havoc with exhaust systems.  Even a bad oxygen sensor can send too much fuel into the catalytic converter, and the resulting heat can wind up destroying this very expensive component. Your exhaust system is made up of several parts, and all need to be i ... read more