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We have been in business since 1996 and fully accredited with the Better Business Bureau since 2008. So if you want an ASE certified mechanic you can trust, come in and talk to me, AJ McKay where customer satisfaction is our priority. Read what our loyal customers have to say on our Testimonials page.

Gulf Stream
Crossroads RV
RV Service & Repair You Can Depend On

For complete RV tune ups to full engine overhauls A.J. McKay's Auto Repair does everything related to engine and drive-train, shocks and brakes. If you have a RV in need of repair please call or contact us to get your RV repaired right the first time. Tow Services available.


(480) 985-2435

Computerized Engine Analysis

Engine Tune-up

Transmission Repair

Wheel Alignment

Brake Service & Systems

Belts and Hose Inspection

Air Conditioning Service

Call today to find out how we can save you money while earning your trust in our quality workmanship.

Our Services...
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BBB Rating


We work hard everyday to be The Best Auto Repair Shop in Mesa, AZ, and we have a A+ BBB Rating to back it up.



Find a better price? Tell us and we will try to meet or beat it! Just be sure to bring in a quote from a local shop and we'll see what we can do.



Whether OEM or after market you can rest assured that we only install quality replacement parts.
Quality auto part in Mesa, Arizon



(480) 985-2435

For Service You Can Count On

Let us at A.J. McKay's Auto Repair make sure you're ready for the heat.  We offer quality full service and repair of most auto and RV air conditioning units.

air conSummer's imminent arrival means your vehicle's air conditioning system is going to be under a serious strain before long. If you haven't had your system serviced in a while, now's the time. While most newer vehicles may simply be able to get away with having their A/C recharged, older cars and trucks may require a little extra attention. If you're confused by the laundry list of parts your mechanic says you need, don't worry, here are the details.

If you think your A/C isn't as frosty as it used to be, but it's still blowing cold, the system just may need to be recharged. While manufacturers used to use a type of refrigerant known as R-12, or Freon, researchers have found it is a leading cause of ozone depletion. As such, it's illegal to use Freon in your car today. Since as late as 1994, manufacturers have used R-134a to keep things cold in the cabin. 

While you can technically recharge your vehicle's refrigerant yourself, its best left to a qualified professional if you're not confident in vehicle maintenance. All refrigerants have a tendency to displace oxygen, which means if you accidentally evacuate the system, the stuff could literally push the air out of your lungs. Not fun.

First Steps
Once you take your car in, technicians will measure the amount of pressure in your system, and if it's low, they'll add enough to get the reading within your manufacturer's specifications. They will then run your car for a few minutes with the A/C on high and use a special thermometer to measure the system's output. If it's not within the necessary parameters, you may have a leak somewhere in your system.

If you do have a leak, your technician will hook your vehicle up to a special refrigerant recovery system and drain any of the harmful gas from your car. At this point, the technician will inspect all of your air conditioning hard lines to make sure there are no obvious cracks. They may add a tracer dye to the system to help out. The good news is, your expensive hard lines are usually made of aluminum and rarely fail. Instead, it's likely one of your system's components is the culprit. First up is your compressor.

The Components
An air conditioning compressor is usually driven by your vehicle's serpentine belt, and as it spins, it pressurizes the system's refrigerant. Simply put, it's this change in pressure that cools the air coming into your cabin. An A/C compressor spins at a dizzying rate, and the more you use the cool side of your thermostat, the more likely it is to eventually fail or leak. One of the main differences between R-12 and R-134a is that the new refrigerant requires supplementary oil to be added to the system to make everything function. R-12 did not. If your compressor has run low on oil, it's possible the interior seals have failed and you'll need a new unit. Unfortunately, compressors aren't cheap.

The best way to keep your compressor from failing is to have your A/C system serviced once a year, including the addition of the right kind of lubrication for your unit. If it does come down to replacing your compressor, most responsible shops will recommend going ahead and swapping out a number of periphery components at the same time. Why? The easy answer is working on an air conditioning system is about as much fun as sticking your hand in a blender. Twice. So to avoid draining your refrigerant, removing your compressor, installing a new unit and refilling the system with new cool stuff, only to have you come back in a week and say it's still not cold enough, it makes sense to replace everything you can. It keeps you from having to waste time and money, and it makes sure they get the problem solved the first time. 

But before we get to all of the tiny bits and pieces that get swapped out during a normal compressor replacement, there is another possible culprit for a leaking system is your condenser. A condenser is basically a large heat exchanger, usually located in the front of your vehicle's engine bay. It looks a little like a small radiator, and since it is exposed to oncoming air, it may get hit by debris as well. If your condenser has been struck by a rock or some other flying material, it may be your culprit.

If your condenser turns out to be ok, your technician may recommend swapping out a number of tidbits, including your receiver dryer, evaporator and expansion valve. If your head's spinning, don't worry. All of the pieces are essential to how chilly things get inside of your car. The receiver dryer, for instance, pulls condensation out of your refrigerant. This is important because when water mixes with R-134a, it creates a corrosive acid that will degrade your A/C system rapidly.

Your evaporator, on the other hand, is essential to the refrigerant's change from a gas to a liquid. That change is essential to how well your system cools. If your evaporator isn't functioning at max capacity, your A/C won't either. 

Similarly, the expansion valve acts as a gatekeeper, deciding how much refrigerant makes it into the evaporator. The more R-134a the system needs, the more the expansion valve opens. Obviously, if your expansion valve isnít working properly, your air conditioning system isn't going to be at its best.

Though a technician could theoretically remove and test each and every individual piece of your system, most of these parts have a similar shelf life. If one has gone bad, itís usually only a matter of time before another fails. Instead of having on-again off-again air conditioning, it's usually best to simply take your mechanic's advice and replace what he or she recommends.


Source: DriveSide

Auto Repair in Mesa, AZ


3130 East Main St.
Mesa, AZ 85213

Shop Hours:
8am-6pm Mon-Fri

(480) 985-2435

(480) 854-9294

Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

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We Stand By our Work. Guaranteed

100 Satisfaction Guarantee on all auto repairs

Here at McKay Auto Repair we always strive to do the best quality work possible. Customer satisfaction is always our number one priority! All work comes with a 12 month 12,000 mile warranty nationwide.

This Is What Our Customer's have to Say.....

Auto Repair customer reviews

5 Star RatingAfter moving to Phoenix from Massachusetts I was concerned that I would have a tough time finding a good mechanic. Fortunately yahoo user reviews pointed me to McKay auto. I have always felt that AJ has charged me a fair price and unlike other shops he doesn't try to sell you things you don't need.


ASE Certified Expert Technicians

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All our mechanics are ASE certified professionals. The National Institute for Automotive Service Excellence (ASE) is a professional certification group that certifies professionals in the automotive repair and service industry. It is an independent, non-profit organization created in 1972 to help consumers distinguish between incompetent and competent automotive technicians.

We Also Have Discount Engines For Sale.


Does your car need a new engine? We sell and install discount replacement engines that will save you a lot of money! Call us today and we will be happy to let you know if we have the engine you're looking for in stock.

now hiring

We are looking for experienced Auto and Lube Techs.  Call (480) 215-7298 to apply.

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Auto Repair in Mesa, AZ

3130 East Main St.
Mesa, AZ 85213