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What is an Evaporative Emissions Leak? Tempe Arizona

Right at the top of the list of codes that we see on cars coming in to the shop here at All Tune and Lube Total Car Care in Tempe are those related to evaporative emissions leaks. These are the faults you hear about that can be as simple as a loose or bad gas cap, but they can indicate more serious problems too.

An EVAP leak code indicates a fault that is permitting gasoline vapor to escape. The first question we’re asked when these codes show up is “Is it safe to drive my car?” and the short answer is sure, but you want to get it taken care of as soon as you can. The Evaporative Emissions System (EVAP for short) is a pollution control system and doesn’t affect drivability, safety or fuel economy. What it does is help keep fuel vapor out of the air we breathe.

The fuel system on a modern car is sealed so that vapor can’t just willy nilly escape in to the atmosphere. There are a couple systems that work together to allow the fuel tank to vent, but trap the vapor produced by gasoline and run it back through the engine. The most important and most easily replaced part of this system is the fuel cap. It’s not hard to tell why. I mean, right there is a big ol’ hole leading right down to the fuel tank. Without a cap that seals properly, nothing else in the EVAP system works.

The other major components are the vapor canister, purge control solenoid and flow sensor. These work together to collect fuel vapor and send it back to the engine intake when conditions permit. The fuel tank, vapor canister, purge control and flow detector are connected by various lines or hoses.

On the whole, the EVAP system is pretty robust, doesn’t require any maintenance (though some manufacturers recommend replacing the charcoal canister from time to time) and doesn’t give much trouble. When trouble does occur the codes that show up most often are the P0440 Large EVAP Leak (That’s the one most likely to be a fuel cap) or something like a P0443 Purge Valve Fault. Sometimes we’ll see a P0442 Small EVAP Leak which can be a bear to locate and repair.

Anyway, I hope you found this useful and if you do have EVAP issues you’ll remember us. Your Local Mechanic, All Tune and Lube Total Car Care Tempe Arizona.

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What Does an Oxygen Sensor Do? Tempe Arizona

An Oxygen Sensor is a little device that fits on the exhaust system of your car and monitors how much free oxygen is there. Pretty straight forward, but why would you need it? I’ll tell you why.

Way back in the day, all gasoline engines were carbureted. That means that they had a mechanical carburetor that used the physics of air moving through a restriction to suck fuel in to the air stream and then in to the engine. Worked great for a hundred years and still works perfectly in some applications but it’s not super precise. If you want performance, fuel economy and low emissions then electronic fuel injection is the way to go. But if you’re gonna have electronic fuel injection you also need a computer to run it, and that computer is gonna need a couple sensors so it can accurately meter fuel to the engine. The primary sensors are a Mass Air Flow sensor and, our buddy, the Oxygen sensor.

The oxygen sensor tells the computer how much oxygen there is in the exhaust (duh). If there’s too little oxygen in the exhaust then there must be too much unburned fuel (hydrocarbons) and the engine is running rich, if there’s too much oxygen then there must be too little fuel (running lean) and your engine is producing nitrogen oxide. Both these conditions are bad for your engine, bad for fuel economy/performance and bad for the environment. By monitoring how much oxygen is in the exhaust the computer can adjust how much fuel is being injected in to the engine and keep it running most efficiently.

OK so far? Now your car probably has at least two oxygen sensors. The “upstream” sensor is the one that does what I just described. There is also a “downstream” sensor and its’ primary job is to monitor the catalytic converter. The catalytic converters’ job is to burn off any remaining hydrocarbons from the exhaust and the downstream oxygen sensor checks to make sure that job is getting done.

Both these sensors will wear out and fail. They have myriad ways of failing and can throw an amazing number of Check Engine Light codes when they do. I’ll get in to that stuff in other posts.

I hope you’ve found this useful! Your Local Mechanic, All Tune and Lube Total Car Care Tempe Arizona

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Nissan Altima Loss of Power Tempe Arizona

Over the years we’ve had several customers coming in with their Nissan cars complaining that all at once, seemingly at random, their car will lose power. They pull over and wait for 45 minutes or so and the car drives normally again. We see this mostly in the summer months and the problem always occurs when the customer is driving for long periods at high speed or pulling a long hill. What’s happening is that the transmission is overheating and the computer that controls the transmission is cutting the power in order to save the transmission. It seems as though this issue affects Nissans’ Constant Velocity Transmission (CVT for short), we haven’t seen the problem in any of their other automatic transmissions and it couldn’t happen with a standard transmission.

A CVT transmission is a wonderful device and has been working well in high power snow mobiles, side by side off road cars and some motorcycles for years but they haven’t gotten all the bugs worked out of them for automotive applications yet. Now Nissan seems to be aware of the problem and they have a transmission cooler available that cures the overheating.

This is what it looks like before the bumper cover is reinstalled

And this is the completed job

We highly recommend using the Nissan transmission cooler because it’s a clean installation without any of the problems that can come up with “will-fit” aftermarket parts. It looks and performs like original equipment since it was designed and built by the folks who manufactured the car. We hope that when you’re ready to get your transmission cooler installed you’ll use us, your Local Mechanics, All Tune and Lube Total Car Care, Tempe Arizona.

Posted in: maintenance repair

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Why Does My Car Air Conditioning Smell Bad? Tempe Arizona

Ever get in to your car or your friends car and get smacked in the nose with the smell of old gym socks or spoiled cheese? Wonderful experience, isn’t it? Real hard to get a second date with that special someone if that’s what they think of when they think of you! The reason for this stench is mold growing in the air box where a device called an evaporator is located.

The evaporator is a radiator like item that is kept very cold by your cars’ AC system. The warm air is drawn through it, cooling the air that is then pushed in to your car so you can ride in air conditioned comfort. You know from the “cold glass on a warm day” thing that water condenses on cool surfaces, right? Well the same thing happens on your cars’ evaporator. So much water will condense on the evaporator that there has to be a drain tube from that air box. The problem is that not all the water drains out and when you turn your car of at the end of a trip and the interior of that box warms up you now have a lovely place for mold to grow.

Here’s what you do about it: Starting right now, about 5-10 minutes before you park your car, turn your AC off while leaving the fan running. This gives the fan an opportunity to dry the evaporator out and deprive that stinky mold of the water it needs to grow.

Next, to try to kill off that mold, you can spray some kind of disinfectant through the system. Roll the windows down, crank the AC on, not on MAX and don’t press the RECIRC button. Spray the disinfectant through the air vents at the bottom of the windshield behind the hood. Let the system run for 15-minutes or so. This doesn’t always work but it’s cheap and you can do it yourself.

If the home-brewed remedy doesn’t get it done you can bring the car in to the shop where we have some special products that can ordinarily kill off the offending fungus. 90% plus success with this stuff.

Lastly, in extreme cases, the evaporator has to be removed and replaced, the air box mechanically cleaned. 100% success but a bit pricey.

Here comes the pitch! Let us do the work! Your Local Mechanic, All Tune and Lube Total Car Care Tempe. Complete Auto Repair and Maintenance.

Posted in: Air Conditioning, maintenance repair

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Car Maintenance Schedule Tempe Arizona

Happy Driver 3-16-15_0If you’re going to keep your car alive and well over the long haul there are certain things you have to do on a regular basis. We call these items Routine Maintenance. Your cars owners’ manual has a list of scheduled routine maintenance services and the recommended mileage for those services, but if you’ve lost your manual here’s a list and the typical mileage intervals.

Every 3,000 to 7,000 Miles
The oil and oil filter should be replaced according to the manufacturer’s recommended auto maintenance schedule with a majority suggesting the oil and oil filter be replaced between 3,000 and 7,000 miles. The low number is for conventional motor oil and the higher number for full synthetic. At the same time you should inspect the level and condition of the transmission fluid, coolant, power steering fluid and windshield washer fluid. You should also check the wipers, tires and tire pressure, brake pads and all exterior lights.

Every 15,000 to 30,000 Miles
Replace the air filter every 15,000 miles or as needed. Every 20,000 miles inspect the battery and test the condition of the coolant. Most 25,000-mile maintenance service requires replacing the fuel filter if your car is equipped with one. Every 30,000 miles inspect the coolant, radiator hoses, HVAC system and all suspension components and on many cars, have the transmission serviced.

Every 35,000 to 50,000 Miles
Inspect and test the battery every 35,000 miles. Every 30,000 to 100,000 miles replace the spark plugs and spark plug wires, and inspect the ignition and air induction systems.

Every 60,000 Miles
Replace the brake fluid, radiator hoses, coolant, power steering fluid and timing belt, have the transmission fluid flushed and replace the transmission filter. Inspect the HVAC, suspension components and tires.
Oil changes and air filters are very important parts of engine maintenance; however, a thorough inspection of all engine, transmission, cooling, brakes and suspension components should also be performed regularly. The owner’s manual provides a routine auto maintenance schedule based on engine mileage for most cars.

Hope this is useful!

From your Local Mechanic, All Tune and Lube Tempe Arizona. Complete Auto Repair and Maintenance

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Where Can My Car AC Be Leaking? Tempe Arizona

Cold CarIf your cars’ AC system is low on Freon (It’s not really Freon, it’s a product called R-134a), you have a leak. No two ways about it. Your cars’ AC is a closed system, meaning that it circulates the same refrigerant over and over again and as long as there’s no leak it will never run out. Now, having said that, some leaks are big enough that they need immediate repair if you want your system to work, and some are very small, so small that you don’t have to re-charge the system but every other year or so.

So where do these leaks most commonly occur? Far and away the most common place for a leak in the AC is at the service ports. There are two of them, one at the high pressure side and one at the, wait for it…low pressure side (Who woulda guessed?). Inside the service ports are little valves that look all the world like the valves in your bicycle tires. Over time the seals that keep them from leaking wear out or get hard and they fail. Easy enough to replace when you have AC service done and we typically replace them as a preventative measure when we re-charge a system.

Now, the AC system in your car has a number of rubber o-ring seals in it as well and these are the second most common spot for leaks to appear. Of those we see more leaks at the AC compressor where the hoses attach than just about anywhere else. After that it would be the o-rings that seal the system to the thermal expansion valve next to the firewall. The best repair for failing o-ring seals is to replace them all. After all, if one’s gone, the rest will be following soon. Bunch o’ quitters!

You’ve probably notice that there are a couple of rubber hoses associated with your cars’ AC too. Those rubber hoses are the third most common point of failure as far as leaks go, usually at the metal collars that attach the fittings to the hoses. You’re pretty safe just replacing the offending item, re-charging the system and going on your merry way.

The last items are way less common: A leaky compressor. The compressor has a seal on the front behind the pulley/clutch that’ll go bad occasionally. Also the compressor splits in half around the middle and there’s a seal that will leak. When this happens get ready to replace the compressor ‘cause it’s really tough to get the darn thing to seal up correctly after disassembling it.

A hole in your condenser. That’s the thing at the very front of your car behind the bodywork that looks like a radiator. They get hit by rocks from time to time, something to which they react poorly.

Way down the list but something we still do see is a leaky evaporator. That’s another piece that looks a bit like a radiator. It’s tucked up way up under your dash and it’s pain to get to. You don’t want a leaky evaporator, they’re labor intensive.

I hope this helps a little.

From your Local Mechanic, All Tune and Lube Total Car Care. Complete Auto Repair and Maintenance.

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Car AC Not Blowing Hard Enough Tempe Arizona

Cold Car 5-11-15Your car’s air conditioner is working but it’s just not blowing air as it’s supposed to. Maybe it only works with the fan in the highest setting or maybe it doesn’t work at all? Maybe the air will come out through the defroster vents or the floor vents but not through the dash? OK, no sweat. Here’s what to look for.

So, you can hear the fan coming on and changing speeds but you’re not getting much air through the vents. Check your cabin air filter. Most cars have a filter that cleans the air coming in to the cab of the vehicle and they get VERY dirty because folks forget about them. We have a couple spectacular examples here at the shop, and I saw one once that was so dirty and clogged that the fan sucked it in to the ducting. This is a common and easily fixed problem. Well, as long as you don’t let the filter get sucked in to the fan.

Can you hear the fan come on and does the sound change as you turn the fan switch? If you’re only getting one or two speeds out of your fan there are a couple of things it could be. We get vehicles in from time to time where the fan only works on the highest setting because the blower motor resistor is burned out. The blower resistor is a little device that typically bolts up right to the blower motor and allows the fan to work at different speeds. When it fries the only speed remaining is high. If all you have is high speed, I’d condemn the blower resistor right away if I didn’t know anything else. Also, the fan switch in the control head can fail, but that’s a bit more rare. If you have to fiddle with the fan switch to get it to work then it’s on its’ way out. Stop messing with it and replace it.

How obnoxious is it to have your AC working great but it only blows through the defroster or the floor vents? I mean it’s nice to have cool feet but is that really what you wanted? No it isn’t! Well, down deep inside the dash of your vehicle, way in there where there is a bunch of scary wires and black boxes and a sign reading “Herre Thar Be Dragons” are a couple widgets called mode control motors. Sometimes vacuum operated, sometimes electric, they control doors inside the air handling system that direct the air one way and the other. They’re plastic motors in plastic boxes with plastic gears. They’re made cheap as dirt and fail all the time. Most often, but not always, they’ll give you some warning with a noisy “click, click, click”. Some of these are easy enough to access, some are a real bear. When you start hearing that “click” bring it in and have it fixed.

There are a number of automatic climate control systems that are run by a computer in your car. We’re not going in to them because they’re very complex and require a skilled diagnostician.

Hope this helps some.

From your Local Mechanic, All Tune and Lube Total Car Care Tempe Arizona. Complete Auto Repair and Maintenance.

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How are Cylinder Heads Repaired? Tempe Arizona

Cylinder Head 5-07-15I just wrote a little article about blown head gaskets. Now I’m going to tell you how the repair usually goes. While there are a number of ways a cylinder head can be damaged, I’m going to focus on the most common way: being warped due to overheating.

So the poor, sick vehicle is in the shop, we’ve done the appropriate tests and determined it has a failed (blown) head gasket. Well, why did it fail? The proximate cause is almost always overheating but why did it overheat? Leaky water pump? Blown coolant hose or radiator? What is the condition of the coolant? Once the root cause of the problem has been located then we can get on with the primary repair, the cylinder head.

The next thing we have to do is remove the cylinder head for repair. If the engine is a V6 or V8 we’re going to strenuously recommend removing both heads and re-sealing them both. Once removed the heads are pressure tested for cracks and to insure the valves are sealing properly. If there are any cracks the head will be replaced. If not, the head will be surfaced, that is machined to be sure the side that sits against the head gasket is flat and smooth enough to seal properly. If the valves aren’t sealing as they should, they and their seats are ground so they will. The valve seals are replaced and the valve springs tested for proper tension. While the heads are being machined we’ll clean the block deck and check it for flatness or other damage.

OK then, the machine work is done and it’s time to reinstall the heads. We use only the highest quality gaskets when we reassemble an engine. Whenever they’re available we use multi-layer steel (MLS) head gaskets. If we’re working on a timing belt engine we’re going to replace the timing belt, the timing belt tensioner and idlers and, most likely, the water pump. We’re going to recommend new coolant hoses and new belts too in order to limit future problems. The old coolant is flushed out, fresh coolant installed and the engine oil is changed.

Road Trip! Well, road test really. Out we go to insure that everything is working as it should. When the car gets back to the shop, one final inspection and it’s ready to go home, just as good or better than before there was ever a problem.

From your Local Mechanic, All Tune and Lube Total Car Care. Complete Auto Repair and Maintenance.

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What Makes a Head Gasket Go Bad? Tempe Arizona

Failed Head Gasket 5--7-15If you’re wondering what it is that causes a cylinder head gasket to fail it could only be for one reason: You have a car with a blown head gasket. Bummer. Expensive too. At least it’s not terminal.

Let’s start off by explaining what a gasket does. If you have a container of some kind and it has a couple of parts that need to seal together so that whatever is inside doesn’t leak out you need a gasket between those parts so they’ll seal. Next time you open a jar look inside the lid. Around the edge you’ll see a rubber ring, that’s a gasket. The weather strip around your door is also a gasket, intended to keep the outside elements out and the nice comfortable inside air in.

Now, the engine in your car is made up of a bunch of parts and there are a number of gaskets used to keep the various fluids (including air) inside where they belong. The gaskets that have the toughest job are the cylinder head gaskets that go at the business end of the engine, between the engine block and the….Cylinder Heads! The engine block is a large chunky piece of metal, often iron, that contains the pistons and crankshaft. The cylinder head is a much smaller piece of metal, usually aluminum nowadays, that contains the combustion chambers and valves. There’s a ton of heat generated in these two, particularly in the head. If you remember your high school physics you’ll know that heat makes things expand, things like your block and heads, then they contract as they cool. This expansion and contraction causes there to be a little bit of movement between the heads and the block. In all modern engines that I’m aware of the gaskets have been engineered in such a way that this small amount of movement doesn’t have any effect on its’ ability to seal, though there were a few engines that had some real problems in the ‘90s.

Overheating is the biggest cause of head gasket failure. The engine block, being the more robust part and not having exhaust gasses routed through it, deals with this heat better than the heads. The heads can get so hot that they warp, expand to a point that they can’t return to their normal shape. When that happens there’ll be spots where the head gasket isn’t held as tightly as it needs to be and it will fail, leaking coolant, compression or both.

Sometimes the cause of failure will be corrosion. Poorly maintained coolant will allow corrosion to eat away at the head or block and eventually tunnel around the head gasket. A lot of times the owner is unaware of the problem until there’s enough of a coolant leak to overheat the engine. Then, see paragraph above.

The key to keeping this from happening to you is maintenance. If hoses are replaced before they fail they won’t blow out. If someone is keeping an eye on your radiator and water pump the chances of dramatic failure decrease. If your coolant is properly maintained it can’t erode your engine. We would like to provide that service to you.

From your Local Mechanic, All Tune and Lube Tempe. Complete Auto Repair and Maintenance.

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How Can I tell if my U-Joint is Failing? Tempe Arizona

Drive Shaft U-Joint 4-28-15_0Seems like I just posted an article about this…Hum, that’s right! I just did one about CV axles! CV joints in your drive axles and u-joints on your drive shaft perform pretty much the same function in that they allow a change in the angle of the shaft while still letting it transfer the torque from your transmission to your drive wheels. The symptoms of u-joint failure are very much like CV joint failure.

When U joints begin to wear, one of the first signs you’ll notice is vibration. A joint that has developed excess play can rattle at slow speeds and vibrate at highway speeds. The vibration at first might be slight and difficult to pinpoint, but it will become worse, usually within a few hundred miles.

If you suspect your U joint might be going bad, find an empty parking lot and turn the wheel all the way to the right or the left and slowly drive in a circle. Most of the time, if your U joint has worn to the point of being loose you’ll be able to hear a clicking noise with each rotation of the drive shaft. I should tell you that you’ll probably only hear the noise if the car is in gear and under a little bit of power. If you have a manual transmission, don’t push the clutch in because you won’t hear the noise.

If you have a way to jack up your car and put it on stands you can visually inspect your drive shaft. With your car safely on stands and in neutral with the parking brake off, slide under your car on your back and twist the drive shaft one way then back while watching the U joints. They should rotate with the drive shaft with no play or sloppiness.

If you are unsure about the condition of your U joints, bring your car in for inspection. If a worn U joint catastrophically fails at highway speeds, the drive shaft can rotate violently out of control and cause major damage to the under body of your vehicle. If the front U joint snaps, the one directly behind the transmission, it is possible for the drive shaft to penetrate the roadway or into a pot hole and flip your car end over end as proven in the television show called “Myth Busters.” That’s not the way you want to wind up in a You Tube video. If you suspect your U joints are going bad, play it safe and have them inspected right away.

If you have any questions, please don’t hesitate to call Your Local Mechanic, All Tune and Lube Total Car Care. Complete Auto Repair and Maintenance

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