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Don’t shoot the juice
Thinking about adding off-the-shelf R134a to your A/C system? Doing it yourself is asking for trouble

Injecting R134a from a can may do more harm than good.

The refrigerant in your truck’s air conditioner is called R134a, and one reason for poor cooling performance is because a system doesn’t have enough of it.

Periodic maintenance by a certified HVAC technician is the best way to make sure the air conditioner is holding its refrigerant charge.

But, what if you’re on the road and warm air is blowing from the vents? It’s tempting to go to an auto parts store and buy a can of R134a, the kind with a hose on it that you can hook up to charge the system.

Don’t do it, says Frank Burrow, warranty and product support manager at Red Dot Corp., manufacturer of heating and air-conditioning systems, components and replacement parts for heavy trucks and other commercial vehicles.

“We see it a lot this time of year,” Burrow said. “A driver assumes the system has lost refrigerant charge because the air conditioner isn’t as effective as he’d like it to be. He goes to the auto parts store figuring to shoot some juice.”

“Shooting juice” – injecting R134a from a can into the A/C system – may do more harm than good, Burrow said.

Auto parts retailers typically carry three varieties of canned refrigerant: R134a with oil for the compressor; R134a with oil and sealant; and straight R134a. Each can be detrimental to your air conditioner.

For example, the oil mixed with R134a may not match the compressor’s original PAG lubricant or ester oil specifications.

“If the compressor lunges, the manufacturer will analyze the oil for its type and viscosity,” Burrow said. “If it detects an oil that’s different from the original, the warranty is null and void.”

More troublesome is R134a with sealant. As it circulates through the system, the sealant will encounter a leak and solidify when it contacts outside air.

The problem is, sealant also can collect inside valves and tubes, clogging them up. Furthermore, A/C technicians may refuse to work on your vehicle if their refrigerant identifiers detect sealant because it can harm refrigerant recovery and recycling equipment.

So, why not use one pound of straight R134a?

“First, you don’t know if you need one pound of refrigerant to replenish your A/C system or some other amount,” Burrow said.

“Second, if your system is losing refrigerant charge, you should see a qualified A/C service technician. He has the expertise and equipment to keep your system working properly.”

Servicing your truck’s air conditioner is not a do-it-yourself job, concludes Burrow.

“What seems like a quick fix really is an invitation to an expensive, time-consuming repair job,” he said.