Spencer Auto Repair Blog

In the automotive world, heat is bad. Take brakes for instance. They work by converting the rotational kinetic energy of the wheels into heat by friction. As more heat is generated, a point comes when the brakes rotors cannot absorb any more heat. They lose their friction and become useless – a phenomena known as brake fade. Therefore it is essential, that a brake can get rid of heat fast. 

Vanes are often added on brake rotors to aid their cooling. Many vehicles come with stock brakes equipped with straight vanes. These are cheaper to make as they do not need two different kinds of castings for their manufacture as they are specific to which side of the car they can be mounted. These vanes pull in more air onto the rotors to speed up their cooling. They cut the air as the wheel rotates and direct it for a better and faster flow. Directional rotors also pull in air from the side of the wheel, and not just from the top like straight vanes. Air coming from the side of the car is obviously cooler than that coming from the top, which could be coming straight from the hot engine. It would be anyone’s guess then, that directional rotors would perform better than straight vane rotors. Some of us however, are not so easily convinced. 

Recently a YouTube video decided to test this for themselves. A Honda S2000 was installed with straight vane rotors on the left front wheel and directional rotors on the front right wheel. A data logger equipped with a magnetic thermal probe was used to measure their temperature. Two different tests were performed. In the first test, the initial temperature of the rotors was noted. Then the car was accelerated to 60 mph and stopped using half brake and half throttle. Then the car was again sped up to 60 mph and then finally stopped. Readings were taken immediately after the run and the same test was repeated two more times. 

The results from these tests would seem baffling to anyone who expects the directional rotors to perform better. In all three runs, the directional rotors heated up to a greater extent than the stock ones - 116, 82 and 105 degree centigrade respectively. Stock rotors’ readings were consistently better at 96, 86 and 92 degree centigrade. The second test was done to test braking while going downhill. The car was sped up to 40 mph and then put in neutral while going downhill. The car’s speed was then maintained with just the brakes without any engine braking. Once the car had stopped, the temperatures were noted again. This test too, was conducted thrice at three different locations. In this test, the temperature changes for the stock setup were 49, 77 and 14 (from 138 to 152) degrees centigrade. The temperature changes for directional rotors were 59, 82 and 24 (from 141 to 165) degrees centigrade. 

Are we caught in some made up marketing ploy to sell more expensive rotors? Let’s dig deeper. If we account for the ambient temperature, the actual temperature difference between the two setup only happens to be 2% for the first test and 1% for the second test. However a negatively biased difference does exist for the differential rotors. The next thing to consider was the mass difference between the two rotors. The stock rotors are in fact a pound heavier than the directional ones. Considering the energy to be the same for both rotors, the same energy is being stored in a denser package in directional rotors.

The most critical point however seems to be the temperature itself. The temperature ranges that this test involved (40 – 190 degrees) were not exactly high. On the track, brake rotors get up to temperature ranges 10 times higher. A better test would then have been, to test the two different setups on the track throughout the day. Under that kind of serious performance, the cooling efficiency really comes into play, more than the mass of the brakes. It’s really a give or take between heat absorption (aided by mass) and cooling efficiency (presence of vanes). This was further proven by a test conducted by Science of Speed, where another Honda S2000 did 56 laps with the two different brake setups. With consistent lap times, directional rotors ran 32.4 degree centigrade cooler on average. The temperature ranges involved here were also as much as 500-1000 degrees centigrade. The conclusion then may be, that performance brakes only shine when they are tested hard. And that we should not let confirmation bias cloud our judgement. 

Everyone knows that an engine is designed to operate with oil. It’s common sense, the law of the land, if you will. Oil acts as a lubricant for the engine while it runs, and is a pretty integral part of the machine. But have you ever wondered what actually happens to an engine that runs without it? Luckily, we have the answer.

In order to understand what happens to an engine without oil, here’s the low-down on what happened during an experiment that compares an engine running with oil to an identical one running without oil. Needless to say, don’t try this at home.

To make this a fair experiment, some variables had to remain constant. In this case, this involved using the exact same engine; a 212cc one-cylinder Harbor Freight Engine. Each test occurred 24 hours apart (with oil first, followed by without oil) in order to allow adequate time for the engine to cool. Each experiment therefore began with the engine at the same resting temperature. The oil used was also kept consistent, with a chosen APA certified Premium motor oil from a grocery store. The point of this choice was to demonstrate how integral even the cheapest engine oil can be in an engine’s functionality and lifespan, particularly when compared with no oil at all.

Five points were monitored on the engine in the experiment including the crankcase at the bottom (where the resting level of the oil sits), the top of the crankcase (where no oil sits), the air cooled cylinder, the exhaust pipe that exits the exhilarator before it enters the muffler, and finally the valve cover (in this case, a push rod style valve with overhead valves).

Given these variables were kept constant throughout this experiment, any extra heat from the engine without oil can be concluded as a result of the lack of oil, which when present acts as a lubricant to keep the engine cool and clean. During the experiment, ambient air temperature was about 15 to 16 degrees Celsius. Prior to the experiment, the engine was stored in a garage away from direct sunlight and outdoor conditions, which resulted in a cooler temperature before beginning.

While you would expect the temperatures of the engine without oil to exceed those of the one with, about eight minutes into the experiment this wasn’t the case. It was interesting to see that the temperatures of the engine without oil actually remained slightly cooler than the engine without, when measured from the outside. The only exception was the exhaust, which was slightly higher in temperature in the oil-less engine than the one that was lubricated. So does that mean if you want your engine to run cool, you should remove the oil? This is definitely not the case, as seen once the engine was opened up.

At the conclusion of the experiment, pulling apart the engine revealed that running it without oil for a mere 15 minutes actually caused some quite severe internal damage. A dark metal-infused oil (minimal left over that hadn’t quite fully drained from the first experiment) remained inside the engine after running without oil, compared with a clear, clean oil from the first run with it. The creation of this negative sludge, which is then distributed throughout the engine as it runs, only does further damage to areas of the engine where the clean oil would normally act positively.

Further examination of the integral parts of the engine such as the connecting rod cap from the crank shaft and the crank shaft itself also demonstrated signs of permanent damage. This is a result of the metals rubbing and churning against one another without the oil to help them slide smoothly, preventing scratches and reducing the likelihood of any damage.

The experiment concludes what we already know to be true - while an engine is able to run for a while without oil, eventually it will combust. In some cases, this will be much more extreme than in this experiment. Bigger engines will likely begin smoking, burst into flames and/or explode if they run without oil for too long. So basically, don’t go driving around in a vehicle with an engine that is lacking in oil. At least now you know exactly what will happen if the oil isn’t regularly checked and changed and why it is so important to ensure your engine is properly lubricated before running it.

Sources

https://mechanics.stackexchange.com/questions/24555/what-actually-happens-when-there-is-not-enough-oil-in-a-car-engine

http://www.thedrive.com/watch-this/8998/watch-what-happens-when-you-run-an-engine-without-oil

http://www.roadandtrack.com/car-culture/buying-maintenance/a33134/engine-no-oil/

https://www.motorauthority.com/news/1109814_what-happens-when-an-engine-runs-without-oil

Few things have raised as much curiosity about a car, as an oil change. How frequently does a car need an oil change? Is it just a big conspiracy being run by the oil companies? At the same time, there are synthetic oils that promises to last for an entire year or at least 20000 miles. What makes this oil so different from others? Can it really last for that long?

Motor oil is essentially a lubricant for the engine. It keeps all the moving parts of the engine running smoothly and cleans the engine of the sludge. Additionally, it acts as a neutralizing agent for the acids in the fuel, helps in forming better seals with the piston rings and carries away some of the heat from the running engine. Basically, it protects the engine from unnecessary wear and keeps things running smoothly. However, the oil breaks down with time and becomes less effective in its job. Running the engine without changing the oil can cause severe damage to the engine. Most mechanics recommend an oil change every 3000 miles. Most car makers recommend one after 5000 miles. Some synthetic oils claim to keep working up to even 10000 miles.

Motor oils are made by mixing a base oil with additives. Depending on the kind of base oils, there are of two kinds: conventional or synthetic. Conventional oils are extracted from crude oils as products found during distillation. Synthetics are made from chemical compounds called polyalpha-olefins. In the past even Canola oil was used as motor oil.

Synthetic oils are better than conventional oils in many ways. A recent test conducted by the AAA on 5 assorted brands, found just that through 8 different ASTM tests. The difference in performance was about 47%. Going deeper into some of the more important tests will further prove the point.

Sheer stability is the measure of how much viscosity the oil loses during operation. At any point where engine parts meet, the friction and heat puts enough stress on the oil to break it down. Conventional oils carry additives called viscosity improvers that maintain the thickness of the oil even at elevated temperatures. They achieve this by expanding at high temperatures and thus maintaining a layer on the rubbing surfaces, at all temperatures. These additives too, are not completely immune to the effects of heat and lose their effect over time. However synthetic oils themselves have these properties and hence do not need to have too many viscosity improvers.

The next benefit is the ability to function during low temperature starts. This was the reason behind the very invention of synthetic oils, as conventional oils freeze at very low temperatures and take some time from startup, to actually start flowing. Synthetic oils are flowing right from the startup, at temperatures as low as 20 below zero.

If its time for your car to have an oil change, come in to Spencer Auto Sales and Service in Mesa Az.

On the other end of the temperature range, we confront the problem of volatility. Engines get hot and volatile oils evaporate on heating. Conventional oils are bad at this as they have a random collection of molecules bunched together. Some of these molecules evaporate earlier than others (thus breaking down the oil), hence leaving the oil thicker and not able to flow as well as it could initially.

The last test was concerned with oxidation viscosity changes which deals with how the oil reacts over time to heat, pressure and exposure to air. Synthetic oils remain unchanged over longer time and thwart the effect of oxidation for longer.

The oil that claimed to last 20000 miles was also tested over 120000 miles on three different turbocharged vehicles with only 5 oil changes throughout the duration at 20000 mile intervals. They also tested the cars for breakdown resistance against oils of other makes. They even went on to break down the engines at the end and measure them for their tolerances. They found the wear to be so minimal that the parts were still within their manufacturing tolerances. This astonishingly, proves the claim this oil manufacturer made. Does this mean that owners now have no need to take care of their cars anymore? Obviously not. Depending on the usage of the car, this claim could be useless to some users and the car still needs its other maintenance needs fulfilled at regular intervals. Still, the fact that one can go without an oil change for an entire year, is truly hard to believe.

If its time for your car to have an oil change, come in to Spencer Auto Sales and Service in Mesa Az.

Winter is coming. Game of Thrones references aside, the coming of winter brings many changes. Winter wreaks havoc on almost every part of a car. Driving conditions change drastically and often even dangerously. No wonder then that today's car makers have warmed up to the challenges thrown by the icy weather and indeed make cars that keep running, when they should just freeze over. A little preparedness however, can make a car ready to handle the worst possible scenarios. Here are six ways through which we can do just that:

Preparing the battery: A car is useless if it cannot start. The battery therefore is downright essential. It need to be able to power the ignition at every possible temperature. However, Lead acid batteries lose almost 20 percent of their capacity at 0 C. They also lose much of their capacity with age. If the battery in your car is small then this may pose a problem. Batteries however also carry a cold cranking amps rating (CCA) that denotes the number of amps that a 12 volt battery can provide at 0 F for 30 seconds while maintaining a voltage of at least 7.2 volts. If low temperatures is a real concern, then look for a battery with a high CCA rating. However a higher CCA means a larger, heavier and more expensive battery. 

Preparing the tires: This is a no brainer. Winter not only causes the roads to become slippery, it causes the pressure in tires to drop as well, as air becomes denser at lower temperatures. Make sure that your tires have sufficient pressure. Additionally the compound used in summer or all weather tires becomes really hard at lower temperatures. Obviously, they do not provide the same level of traction as winter tires. Traction is necessary as roads are slippery and accelerating, braking and controlling the car is especially difficult. 

Preparing the brakes: The other factor that plays into stopping a car is obviously the brakes. Brake pads and rotors are probably the most abused and neglected parts of any car. Especially for winters, every driver should make sure that their brakes are usable. Start by inspecting the brake pads to make sure that there is enough material left to provide sufficient friction. Today many brake pads come equipped with wear indicators that produce loud, unmistakable and hard to ignore screeching noises, reminding the driver of their condition. 

Preparing the engine: The functioning of any engine largely depends on the engine oil. Every engine comes with a recommended engine oil, graded specifically for it. This oil grade can very easily be found on the fuel cap or the owner’s manual and every car owner knows this. What is however not so well known is that certain cars recommend different engine oil viscosity ratings depending upon the temperature ranges they are expected to be running at. This information however, is often buried inside the car’s owner’s manual. 

Preparing the wipers: Continued visibility in colder climates is not something to be taken for granted. As essential as wipers are, they are especially finicky. There are many possible ways a car’s wipers can stop working. Therefore it is necessary to make sure that they are in working condition to take care of the precipitation that will be hitting the windshield. Keep an eye out for cracked rubber on the wiper surface. You should take immediate action, if you find them skipping across the windshield. Of course, in this case the only solution, would be to replace them. 

Equip yourself: A little preparedness can go a long way. At the same time, emergencies can occur for even the most well prepared driver, leaving them stranded in the middle of nowhere in the freezing cold. Some essential equipment therefore, should always be present in the car. This can include things like an ice scraper to remove frost from the rear window, an escape tool to cut seat belts and break the glass in a stuck car, a shovel and rock salt to create traction when the road proves to be extra slippery, flashlight, blankets and road flares to survive any accident, jumper cables to help any other unlucky driver in need of a jump start or simply a AAA approved emergency kit that contains as many as 76 items to cover any possible emergency. 

Every car is limited by the surface it travels on. The wheels need to find traction, if they want to deliver the power of the engine to the ground in any usable form. Off the road however, there is no guarantee that the driven wheels will find traction, let alone a surface to drive on. 

4 wheel drive systems were invented for just this scenario. They allow power to be sent to either two or all four wheels, thereby allowing the car to grip in any condition. The driver can switch between different modes depending on the driving conditions. These vary from 2HI (all power to rear wheels) which is best suited for everyday driving on paved roads, 4HI (power is split 50-50 between the front and back wheels) for slippery or uneven conditions and 4LO (same as 4HI but geared towards providing more torque) when the going gets really tough and the car needs to literally crawl over the terrain. How does a 4WD system benefit in different conditions? For that we need to understand 4WD first. 

A 4WD system can send power to all wheels. The power from the engine goes through the transmission, like any other car. This could then go to a reduction gear setup (also known as a high/low gear setup) or directly to a transfer case. This reduction gear setup allows the driver to get a lower output speed for the same torque. The transfer case allows the car to switch between 2WD and 4WD and can also choose whether it runs on low gear mode or high gear mode. Power is then sent to the rear differential by an output shaft. The output shaft connecting the front differential, is powered by a chain drive (more commonly) or by gears. The differentials on the axles can themselves be locking or open. An open differential allows both wheels on the axle to move at separate speeds. A locking differential can lock the wheels on the axle and force them to move at the same speed. These differentials themselves, can be electronic or mechanical. Limited slip is another term that gets thrown around a lot in these circles. Using the brakes on the wheels or a differential, excess power from the engine or slip on either wheel is controlled by braking the wheel and sending the torque from that wheel to the other wheel on the axle which is not slipping. If there is already a lock on the differential, then obviously there is no need for the limited slip. 

From this brief itself, we can gauge that the whole system is designed so that in any given condition, there is at least one wheel that keeps getting power from the engine. If there is only one tire without traction (maybe it’s slipping or completely off the ground) then the wheel would normally just spin uselessly. In a 4WD system, the center differential can be locked using the transfer case along with the rear differential. This means that for the free wheel to spin, the rear wheels also needs to spin as they are connected by the drive shafts. Since the other tires, indeed do have traction, the free wheel does not spin and the car can move on. 

If instead, beyond all probability, three wheels end up in the air or start slipping, a much different and dangerous situation arises. All these three wheels can end up spinning even if they are in lock as demonstrated in the last situation. However the wheel with traction can be braked using the limited slip differential. This stops the other slipping wheels from spinning and diverts all the torque to the usable wheel. Therefore even in such a dire situation, 4WD comes through nicely.

The effect of the three layouts can also be shown through an acceleration test as demonstrated by a recent YouTube video. The test involved measuring the 0-30 mph acceleration time of a Nissan Frontier Pro-4X, in 2WD HI with no traction control, 2WD HI with traction control, 4WD HI and 4WD LO. This revealed that the fastest time of 3.2 seconds was achieved for 4LO, which was a quarter of a second faster than the other timings. Although there was a gearing advantage involved with the 4LO setup, the role of increased traction cannot be denied. 

In this way, 4WD allows everyday people to brave the outdoors (or cross a driveway covered by particularly slippery leaves) in the same cars that take us to our offices. All thanks to some clever engineering.

If your 4WD vehicle needs to be repaired contact Spencer Auto Repair in Mesa Az.

Vehicle tires are a very crucial factor determining road safety. They are the only connection between the vehicle and the road and therefore contribute a lot to performance. This implies that choosing the right tires is a delicate exercise and should be approached with due diligence.

Different seasons come with various driving challenges. That is why manufacturers have seen it fit to device different tires to handle the varying conditions. There are winter tires, summer tires and all-season tires in the market all of which have marked features that set them apart.

What Makes Winter Tires Different?

Understanding the factors that differentiate winter tires from all others will help us better understand why you shouldn’t run winter tires all year. Here are some of the noteworthy differences:

Chemical Structure

The main difference between winter tires and regular tires is the rubber compound used in the former. Driving in winter means having to contend with slippery surfaces and therefore grip is compromised. However, the compound used in winter tires keeps them soft even in the lowest temperatures. This makes them remain flexible and have a firm grip at all times keeping the vehicle stable while accelerating, decelerating and even stopping.

Tread Design

The tread patterns and depth on winter tires is also more pronounced than in all-season tires. These tires normally feature an asymmetrical pattern. On the outboard side, the treads are bigger and aimed at reducing tire squirming and retaining stability while taking corners. The inboard treads are much smaller and they assist in maintaining traction while on a straight snowy course. 

Siping

This refers to the thin slits that are cut into the surface of winter tires. They provide a bigger surface area meaning improved traction. They therefore make it easier for the tires to get a firm grip on snow. These cuts are almost invisible but they play a big role particularly when brakes are applied. They effectively help to bring the vehicle to a stop with greater ease and prevent sliding.

Studs

These are tiny metal pieces embedded into a tire to help the vehicle get a firm hold on icy surfaces. They also serve to improve traction by providing additional grip. They are however not as common these days and they are outlawed in certain states.

Reasons against Using Winter Tires in Warm Weather

The inconvenience of changing vehicle tires might at times make it tempting to keep the winter tires on even when the season comes to an end. Some reason that the soft rubber will always provide a firm grip thinking that the only issue is that they might wear out faster. Consider some reasons why you should not run winter tires all year no matter what:

Significantly Extended Stopping Distance

A firm grip on the driving surface determines how well your vehicle’s brakes function. When using winter tires during warm weather, the heat compromises the soft rubber compound. This means that even as you brake, instead of holding shape, the tires slide and the material shears. It takes longer to come to a stop and in case of a collision this will mean a greater impact.

Increased Risk

The extra wear that befalls winter tires when they are used in winter could mean the difference between life and death. As tires wear out they become smooth and therefore have very low traction. This means that they will take a lot longer to bring your vehicle to a stop and might therefore compromise on passenger safety.

Lower Performance

The same factors that enhance the winter tires’ performance on icy surfaces are the very same ones that reduce performance on regular road surfaces. Unlike all-season tires, they are considerably soft and therefore squishier. This makes it particularly hard to maneuver the vehicle when making turns. They do not respond as fast as their all-weather counterparts and this is not only inconvenient but also risky.

Noise

Studded winter tires in particular are noisy and annoying. The sound of metal studs digging into the road is not the most interesting one. Additionally, it causes damage to regular road surfaces and pavements explaining why it is either outlawed in some places or strictly limited to use in winter in other places.

Conclusion

Winter tires are made using specialized technology and material specifically for use on snow and ice. It is a lot more expensive to use them on regular roads as they won’t last very long. It is also very dangerous as proven above. So take the few extra minutes to change to all-season tires when spring begins and enjoy better performance, enhanced safety and a lot more convenience. If you need help changing your winter tires and need to get some summer tires contact Spencer Auto Repair in Mesa Az Today.

Spending money on good tires is never a priority for most of us. Like the bottom shelf of a supermarket aisle, they just don’t fall in our line of sight. We’d rather spend money on things like aftermarket rims and polishes. Additionally, many of us feel that more expensive tires are merely a cash grab.

Honestly though, tires have a dramatic influence on pretty much every aspect of the car. The profile of the tire determines the ride quality, noise, handling characteristics, grip, mileage, tendency to aquaplane and even the look of the car. They also help in effectively using the power that the engine generates and restricts how fast we can drive. A large amount of torque is useless, if the tires cannot grip the road.

Tires connect the car to the ground. Additionally they are required to perform in harsh environments. Naturally they are the most abused part of the car. Winter tires need to hold onto slippery icy roads, even as the ice melts at the contact patch. They regularly cushion the driver and the passengers from crater sized potholes. Still most people are reluctant to spend money on good tires.

Most of us are satisfied with tires that can just stay inflated. Tread wear does not become an issue till the tires have gone completely bald. Mismatched tire sizes are routinely ignored, as are tire pressure warning lights. Drivers become too lazy to change their tires with the change in the weather. Inferior quality tires are used for saving as little as 100 dollars. It isn’t difficult to find tires of different makes or different speed ratings on different wheels of the same car. Clear signs of bad tires like periodic noises and vibrations are ignored without a thought. “It still runs” is our favorite defense.

Many of us will still argue that this tire related paranoia is not justified. People living in cities with smooth roads consider good quality tires to be unnecessary. Most of them only use their vehicles for commuting and don’t indulge in off roading or racing of any kind. However, there is one aspect where good quality tires can make a world of difference – the difference between life and death.

That aspect would be braking. Tires have a tremendous impact on a car’s braking performance. A YouTube video recently explored actual brake performance by comparing braking distances, stopping times and G-forces. This test was conducted between an old Fuzion HRI/VRI all weather tire setup against a new Bridgestone RE-71 R summer tire setup, on a Honda S2000 stopping from 60 mph. Both the tests were conducted at nearly the same temperature, same location and similar tire pressure. Although the test was not the most scientifically accurate, its results are still eye opening. The best results that could be achieved for the first setup were 136.15 feet, 3.41 seconds and -0.999G. The worst however were 143.9 feet, 3.58 seconds and -0.926G. For the second setup, the best results were 107.93 feet, 2.63 seconds and -1.193 G. The worst were 112.3 feet, 2.84 seconds and -1.165G.

These results are astonishing. The first setup’s braking performance is not just bad, it’s also inconsistent. The stopping distance itself, shows a variation of over 8 ft. This variation gets bigger on successive tests, while the second setup actually improved braking distance in successive trials. The biggest difference can be seen between the best timings for the second setup versus the worst timings for the first setup. A difference of 36 feet and a whole extra second to react could be lifesaving in an emergency. If this still doesn’t seem that big a deal then here’s another
perspective. The difference between the two performances, is the same between that of a Cadillac Escalade and an Alfa Romeo 4C or between a two ton SUV and a lightweight sports car.

As for price, the difference comes down to 215 dollars. Is this cost worth it? Considering the benefits, it would surely seem so. But if you’re still not convinced, then just take this one lesson from this article. Don’t buy tires based solely on price. At the same time, the most expensive tires aren’t necessarily the best for your car either. Consult customer reviews, independent tests conducted by auto magazines and consumer reports. Buy the correct tires for your car according to conditions and requirements. Make an informed decision.

If you are looking for top quality tires, contact Spencer Auto Repair in Mesa Az at (480) 500-1143. We can help you find and install the safest tires available for your vehicle.

How Does it Work

A car is an almost airtight, metal, plastic and glass box. It absorbs and retains outside heat and moisture without letting out the inside heat and moisture and if the outside weather isn’t bad enough, it is attached to a hunk of metal that constantly creates countless fiery explosions. So cars tend to get hot.

Air Conditioners therefore, are indispensable but how do they work?

The most important ingredient here is the refrigerant. This absorbs the heat from the air entering the cabin making it cool. This is a gas, most probably Freon R134a. Unlike its predecessor it has little impact on the ozone layer and has a boiling temperature of −15.34 F or −26.3 C. This fact becomes important later.

This refrigerant is circulated throughout the AC circuit. First this gas is sent into the compressor. It is driven by the engine itself with the help of an engine belt. It comes in at low pressure and temperature and is compressed to high pressure and temperature. It is then sent into the condenser to cool off. The condenser is at the front of the car, with the radiator for better air flow. Air is captured by a fan or by the forward movement of the car itself. This air condenses the high temperature refrigerant gas to liquid form. The air then gets sent to a receiver dryer through a filter (to remove any harmful debris) and a desiccant (to remove any water). (Any water mixed with the refrigerant could freeze in the evaporator and damage it) Next, it goes into either an expansion valve or in some cars, an orifice tube. This controls the flow of the refrigerant into the evaporator. As the liquid expands in the expansion valve, it loses speed and pressure and just as the gas gained temperature under pressure, it loses that temperature when the pressure drops. Despite this drop, the refrigerant is still in a liquid phase as it enters the evaporator.
This very cold refrigerant is what cools the air entering into the cabin. A cabin fan blows air from the front of the car onto the evaporator, which along with the expansion valve, sits under the dash. These cooled fins absorb heat from the air, and the cooled air is sent into the cabin through the vents. The refrigerant however, has absorbed all the heat from the ambient air. Because of its low boiling point (as mentioned above), this heat literally boils it- i.e. it turns into a low pressure and temperature gas. If the car uses an orifice tube, it goes into an accumulator, which removes any remaining liquid from entering the compressor. After this, it goes into the compressor again and the cycle repeats itself.

Recharging the AC

Because of modern engineering, ACs have become very reliable. For most people the only maintenance issue likely to come up, would be a need to recharge the refrigerant level. Many companies provide kits through which this becomes a DIY task. They may even come equipped with a reusable pressure gauge connected to a dispenser tube and a temperature indicator. Some even have additives that seal slow leaks by causing the O Rings and gaskets to swell up. However if your system has leaks, it is best to get it fixed by a professional at Spencer Auto Repair.

Just put the AC on max and ensure the compressor is running and that the clutch engages. Then find the low pressure port to which you can connect the dispenser of the refrigerant. This port is often marked with an L on the top. Then connect the pressure gauge to the port. Listen for the reassuring click to ensure it fits. This next part is a bit tricky you must ensure that the bottle pressure is in the safe zone at all times to avoid overcharging. Twist the outer ring of the gauge to match the outside temperature. The pressure at this temperature should lie within the safe zone, as marked on the pressure gauge. Once this is ensured, you can detach the dispenser tube, attach the bottle and start recharging. Keep the bottle upright and keep it turning sideways by 90 degrees and checking the pressure gauge every few seconds. Charge till the needle falls between the marked pressure ratings or the suggested pressure and replace the cap. If you end up overcharging then you’ll have to take it to a professional, so be careful.

If after you recharged the systems the care is still not blowing cold air you might have a problem in another part of the system and you should take it to your local mechanic to have it checked. If you are in the Mesa Az area, Spencer Auto Repair can fix any AC system for all makes and models.