MACS Summer of Service Videos

Calling all MACS members! MACS is launching the summer of service videos!

Send us a short mobile A/C technical tip video less than 10 minutes that explains a service procedure or is educational and not overly commerical and we will post it on our website homepage for one week this summer.

You must send us an embed link and again not overly commercial it is fine to mention a product but we are looking for solid tech tips.

This is a great opportunity for MACS member companies to get more traffic for their service videos and help educate the industry.

Email your video embed link to

MACS reserves the right to refuse any video we deem not to be appropriate.

You must be a member of MACS to participate.

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Honeywell opens new R-1234yf plant in Louisiana

Honeywell announced that it has started commercial operations at its new manufacturing plant in Geismar, La., to meet the growing global demand for its next-generation mobile air conditioning refrigerant. With this start-up, the plant has become the world’s largest site for producing HFO-1234yf, sold commercially as Solstice® yf.

Have you ever wondered what a refrigerant plant looks like? Here are some photos of their new operation courtesy of Honeywell.

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Clinics, clinics and more mobile A/C clinics!

MACS has been busy training all around North America. Here are a few photos from the clinics…

MACS Mobile A/C Update Class in Bethlehem, PA with MACS Steve Schaeber

MACS heavy-duty mobile A/C class at Arctic Traveler with MACS Mike Bailey

MACS Mobile A/C Update Class in Waxahachie, TX at Tubes ‘n Hoses wit Jerry Lemon

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Do you have the right tools to repair mobile A/C systems?

Global Service Horizons


2017 MACS Worldwide Trade Show puts the future in plain sight

May I share something with you? Of all the automotive industry events I cover each year, it is the annual Mobile Air Conditioning Society Worldwide (MACS) Training Event and Trade Show that I most enjoy attending. Now let me tell you why.   Read the whole article

Download the May 2017 Issue


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What happened at the 2017 MACS Training Event?

The April 2017 issue of award-winning MACS ACTION magazine is now available with a comprehensive wrap-up of all the training classes presented at MACS 2017 Training Event and Trade Show. View what’s inside

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Robinair and MACS Worldwide to provide free Section 609 test prep webinar and online test on May 9


Robinair and MACS Worldwide to provide free
Section 609 test prep webinar and online test on May 9

Robinair is partnering with the Mobile Air Conditioning Society (MACS) Worldwide to provide a free Section 609 test prep webinar for training and certification for up to 125 technicians on Tuesday, May 9 at 4 p.m. EDT. The webinar will be broadcast on a private YouTube channel. Registrants will receive the link to the webinar in advance of the webinar and a link for the test after the webinar.

The webinar will take approximately 90 minutes and at the end technicians can become Section 609 certified to work on vehicles using R-12, R-134a and R-1234yf refrigerant when they take the online test provided and successfully pass the test.

Interested technicians can register by calling 215-631-7020 x 0 or by registering online at under the EVENTS TAB.

When technicians register for the webinar, they will receive a link to the webinar in advance of the event free of charge and courtesy of Robinair. Technicians should take the online test immediately after viewing the webinar on May 9. If they pass the test, Section 609 credentials will be sent to them. Should a technician fail the test, one online re-test will be issued.

R-1234yf refrigerant is gaining popularity among vehicle manufacturers because it reduces the environmental impact of A/C systems in vehicles, helping manufacturers meet stringent vehicle emissions standards. Automakers can receive emissions credits for using environmentally friendly refrigerants, meaning aftermarket technicians will begin to see an increase in vehicles using R-1234yf.  The number of vehicles using

R-1234yf is expected to increase exponentially in the coming years as the refrigerant replaces the current industry-standard R134a.

The MACS refrigerant recovery and recycling program was developed to meet the requirements under Section 609 of the Clean Air Act and was formally approved by the U.S. Environmental Protection Agency (EPA), effective Aug. 13, 1992.  Since then, more than one million technicians have achieved Section 609 certification through its program. Throughout the years, MACS has continually expanded its certification program to reflect industry changes in technology, service equipment, procedures, tools, alternative refrigerants and changing government regulatory requirements.

“It’s a very natural fit for Robinair to partner with the MACS certification program to educate, train and certify today’s technicians on the latest breakthroughs and advancements in the mobile air conditioning industry,” said Tim Wagaman, senior product manager, air conditioning & fluid products, Robinair. “As R-1234yf becomes more prevalent in vehicles on the road, technicians and shop owners need training to recognize which refrigerant is being used, how to handle it safely and how to make sure they are properly equipped with the right machines and tools to service them.”

Since 1981, the Mobile Air Conditioning Society (MACS) Worldwide has been the advocate for service and repair owners, distributors, manufacturers and educators making their living in the total vehicle climate and thermal management industry.

MACS Worldwide empowers members to grow their businesses and delivers tangible member benefits through industry advocacy with government regulators and by providing accurate, unbiased training information, training products, training curriculum and money-saving affinity member services. MACS has assisted more than 1-million technicians to comply with the 1990 Clean Air Act requirements for certification in refrigerant recovery and recycling to protect the environment.

To learn more about MACS Worldwide visit our website at The MACS 2018 Training Event and Trade Show, A/Ccess will take place February 14-17 at the Caribe Royale Hotel and Convention Center in Orlando, FL. A current calendar of regional training can be found on the training page of MACS website.

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What you don’t know can hurt your diesel engine


By Lauren Lewis

An introduction to heavy-duty coolant technology and best practices

Coolant has a few basic jobs in a vehicle’s engine, not the least of which is to absorb heat from components and dissipate it through the radiator into the surrounding air.
But the work is more demanding in a heavy-duty diesel.
The typical engine in a commercial truck, bus, or piece of off-highway equipment uses a wet-sleeve design, which means the pistons operate in cylinders surrounded by cast iron liners that come into direct contact with the coolant.
The combustion process causes these liners to vibrate rapidly, like a bell. This produces tiny vapor bubbles on the liner wall, and they implode with enough force to take little chunks out of the sleeve liner when they collapse. Left unchecked, these cavities will perforate the liner and allow coolant to mix with oil—a potentially catastrophic situation for the engine.
Heavy-duty coolant circulates chemicals to protect from this type of damage. In addition to removing heat and protecting liners, the coolant must to not react with the various materials it touches—aluminum, cast iron, copper, brass, and solder, plus non-metallic components like hoses and gaskets, including silicone. If the pH balance is too low, it can corrode cylinder blocks, heads, and liners. If it’s too high, it can harm gaskets and softer metals.
These are big tasks in addition to protecting against freezing and boil-over. Furthermore, the coolant’s chemical condition is constantly changing, so it’s important to maintain it as you would any other component on the vehicle.
Coolant classification
There are green coolants, red coolants, blue coolants, yellow coolants… In fact all heavy-duty coolant starts out as a colorless blend of water and a base, the most common being ethylene glycol (EG). The base lowers the freeze point and raises the boiling point of the coolant so it can transfer heat in more extreme temperatures than water alone can handle.
That being said, there is no universal color convention in the industry, and coolants of the same color are not guaranteed to be similar in composition or performance.
Instead of color, focus on performance standards, base type, and inhibitors.
Performance classification refers to a set of minimum testing standards or OEM specifications. ASTM D6210 is the American Society for Testing and Materials’ standard for glycol-based heavy-duty engine coolants and it evaluates a product’s ability to protect against liner pitting and scale. OEM standards go a step further to meet the needs of their specific engines, applications, and warranties. Check the packaging or product brochure to make sure your coolant meets your engine manufacturer’s requirements.
Type classifications can be made based on the coolant base type and inhibitor chemistry. EG-based coolants work in a wide range of climates and account for more than 90% of heavy-duty coolant sold in North America (propylene glycol is a less toxic alternative). Most OEMs require that the base be present in a concentration between 40 to 60%; you can check this in the field using a refractometer.
Finally, there are three terms to describe inhibitor chemistry: conventional, hybrid, and OAT (Organic Additive Technology).
Most conventional coolants come fully formulated with the proper mix of water, glycol, and SCAs and should meet ASTM D6210. This eliminates the need to “pre-charge” the coolant with supplemental coolant additives (SCAs).
Heavy-duty OAT coolants use organic acids like benzoic, sebacic, and adipic; OAT coolants don’t require SCAs and provide extended service intervals. Hybrid (HOAT) coolants typically have a longer life and service interval than conventional coolants but require more maintenance, which may include adding SCAs.
Both are initially more expensive than conventional coolant but cost less to maintain over the life of the vehicle. An extended service interval coolant typically only needs additive replenishment and filter change once per year, compared to conventional coolants with standard service intervals where the additive and filter are replenished at each oil change interval.

Common failures
Using the right coolant is important to preventing heavy-duty engine failures. Let’s walk through some of the most common:
•    Liner pitting: You’ll see pitting most frequently on the side of the liner where the piston strikes just after the cylinder fires, and to a lesser degree on the opposite side where the cylinder strikes on the up-stroke. However, this type of damage can show up anywhere the level of vibration is high. Because of variations from cylinder to cylinder and engine to engine, no two liners will appear the same.
•    Additive Dropout: When additives become unstable they can leave the coolant system unprotected against corrosion. Dropout can happen for several reasons, including coolant contamination, over-treatment of SCAs, and an improper mix of water, glycol, and inhibitors. Some additives will collect in the cool areas of the engine when instability occurs and impede heat transfer.
To reduce the risk of dropout, make sure the water used for mixing coolant is of good quality; most tap water is hard and can react with additives, causing them to become insoluble. When adding SCAs or extenders, more is not always better. If the additive concentration gets too high, the coolant will not be able to hold all of the additives in solution.
•    Water Pump Failure: Hard water and additive dropout can lead to deposits on water pump face seals. So can particulate left by the manufacturing process of engine hardware.
Filtering these contaminants will not only reduce water pump failure, it can guard against engine wear, radiator failure, overheating, thermostat failure, and other coolant system component problems.
Water filters containing SCAs are a reliable way to meter out supplemental additives and coolant extenders during a service interval. For coolant systems above 20 gallons (76 liters), or if a liquid extender or SCA is used instead of a filter to replenish the SCA, use a blank water filter. For OAT coolants, blank water filters should be used.
•    Corrosion: Historically, heavy-duty engines used a lot of cast iron and copper. But more heavy-duty coolant systems are incorporating aluminum radiators and oil coolers. The manufacturing process for these components uses a residual brazing compound that can partially dissolve into the coolant and introduce contamination. Some of the additives in conventional and hybrid coolants can have an adverse reaction in environments with brazing compound contamination and aggravate aluminum corrosion. When corrosion begins to occur, the aluminum is weakened and is prone to stress fractures.
OAT coolants are typically more robust for protecting against this type of contamination in the cooling system.
It’s estimated that 40% of all engine problems originate in the cooling system, meaning that selecting and maintaining your coolant is critical to protecting your equipment. When in doubt, follow the engine manufacturer’s recommendations for coolant type and service intervals. f

Lauren Lewis is Product Development Engineer, Coolants & Chemicals, at Cummins Filtration. She has a BS in Chemistry from Tennessee Tech University.

This article appeared in the March 2017 issue of ACTION Magazine.

Read the whole issue at this link

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Meet Jay Brown of Nissens North America

Meet MACS member, Jay Brown, general manager of Nissens North America, Inc., located in Grapevine, TX. Nissens, headquartered in Denmark, has been a member of MACS since 2004.

Nissens manufactures radiators, condensers, evaporators, compressors, oil coolers (engine, transmission, power steering), receiver driers, engine/condenser fans, heaters and intercoolers. The company’s business is equally divided between engine cooling systems and HVAC.

Nissens is one of the largest suppliers to the heavy-duty, bus and specialty markets in Europe.

MACS’ emphasis in 2017 is on exploring new vehicle technology, so we asked Jay, as a MACS member and component manufacturer, what concerns he has about electric vehicles, hybrids and other alternative fuel vehicles. Jay responded that he does have concerns about “how this new technology will affect replacement rates. New technologies will still require heat exchangers and some type of HVAC system for the passengers. The change will be the value of the heat exchangers and the replacement rates.”

Every business has its challenges, and we asked Jay what he sees as the challenges for Nissens. “Honestly, there are three. One is the value versus the cost of products. Some businesses purchase strictly on price without recognizing the true value they are receiving, which means they do not understand their true costs. The second is training. Even today some businesses refuse to see the value in continuous education. They are stuck with the mindset, I have always done it this way. But that kind of thinking no longer has value. What they did yesterday will not work on tomorrow’s vehicles. And my third concern is a shrinking distribution market. We are seeing more and more consolidation.”

What is Nissens’ most successful strategy? Jay explains: “Nissens’ growth plan remains on track.  The ever-expanding product range has allowed us to maintain our leadership in the European range of vehicles while letting us become specialists in Korean and other makes.”

Nissens has devoted company resources for many years to be involved as a MACS member, exhibitor and sponsor. We asked Jay what he sees as the  payoff for Nissens? “MACS has always been an organization that is at the forefront of training and sharing global regulatory information as our industry changes. We need that advocacy voice in order to be heard and the training to keep our members up to date. The monthly MACS Service Report information we receive allows me to verify what I am learning internally from my product team along with what I am seeing in the field.”


Nissens was an exhibitor at MACS 2017 Training Event and Trade Show in Anaheim, CA this past February, and we asked about its experience. “Nissens has participated both as an exhibitor and as an attendee over the past 14 years. As an exhibitor, we attend to find new customers, inform existing customers of changes, and the training.  As an attendee, we are there predominantly for the training and social aspect.”

Jay has been in the aftermarket for many years. His advice to his fellow MACS members is to “Recognize your business weaknesses and concentrate on your strengths.”

This article appeared in the March 2017 issue of ACTION Magazine.

Read the whole issue at this link










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MACS AG HVAC clinic in Norfolk, NE

MACS held our first ever agricultural HVAC clinic at MACS member Northeast Community College in Norfolk, NE on Friday, March 24 attended by 31 technicians. MACS wants to thank Doug McKibbon of Northeast Community College for his invitation to use their beautiful facility. Many thanks to MACS member Al Mindermann for teaching the class and sharing his expertise.


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Truck heater control valves

By Chris Tyson, MACS heavy duty contributor

We have several Class 8 trucks in our fleet and when temperatures begin to drop outside many of their owners visit our shop for heater-related repairs. That’s exactly what happened when the operator of a 1992 Marmon 57S dropped his truck with a no heat complaint. It was a pretty quick diagnosis too, considering that the temperature knob on the dashboard wouldn’t slide from cold to hot (without the risk of breaking it). It also didn’t take long to feel the heater hoses and find warm coolant on one side of the heater control valve, while the other side was relatively cool. After disconnecting the cable, the dash control moved freely, so we determined a replacement valve should do the trick.

That’s not as easy as it sounds when dealing with a truck this old. Most parts can still be found (especially with the help of some MACS distributor members), but sometimes it takes trial and error to get it right. We looked through catalogs, matched up pictures, ordered a replacement valve and installed it. Now the truck has heat but the dash control is backwards; we get heat when the knob is on cold!


Closer inspection of the valve shows us why. This type of valve is directional, meaning that when the cable pulls up on the pin, water is allowed to flow; however, when the cable pushes down, the flow is cut off. See Figure 1. We need the opposite valve, which closes when the cable is pulled up. It appears they could have set this valve up to be more universal if there was a pin on the other side of the arm and a cable clamp opposite the bolt, but that might not work in other situations. Either way, we’re going to need a new valve.


Caption Figure 1: This heater control valve is universal, but directional.


This is where details really matter because there are a multitude of valve variations. Some valves are manually controlled, and the operator has to physically get out of the cab to open or close a valve (or valves) in the engine compartment any time they require heat. Others, such as this Marmon are cable operated, while still others are controlled by vacuum or even electric motors. Then there’s the configuration of the valve itself which is dependent on how it’s mounted and where it’s located under the hood. You can get “T” valves, 90° valves (in ↰, ↱, ↲, ↳, ↴, ↵, and other orientations), offset valves where the inlet position is higher or lower than the outlet (rather than being directly inline), various sized ports (such as ¾” inlet and ⅝” outlet), and even valves with differing degrees of cable-to-valve-orientation offset. These details seem small, but are necessary to coordinate heater valve operation with the operator’s dashboard controls.


Our driver will have to live with this arrangement until the new valve arrives. In the meantime, details like these need to be shared with other technicians to help them avoid making the same mistakes. That’s part of what makes a MACS membership so important! Do you have a similar story?

Do what I did and send it to and share your experience with the MACS community. You’ll be glad you did!

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