MACS Monthly Newsletter - 2017 - NOV4

typically to 12-16 oz, and the systems themselves are much
tighter. The reason is a new generation of seals and EPA credits for systems that use them. Yes, today's systems are critical
charge and might take just four to eight ounces of R-1234yf.
So, the difference in cost for refrigerant might be as little as
$20. Do you really want to go to the illegal practice of buying adapters and switching the entire charge to R-134a after
a service procedure that is likely to be in the ticket range of
several hundred dollars? And what would you do with the
R-1234yf you remove from the customer's system? Venting
it is illegal per EPA. If you collect it in a storage tank, then
charge the customer for a vehicle system A/C charge (even if
you don't specify with what, but use R-134a) you would face
an interesting legal issue if the higher value of that R-1234yf
were not accounted for in the customer ticket.
Keep things simple: charge R-1234yf systems with R1234yf. The price is coming down, look for a good deal from
a reliable supplier, and most important, check the purity of
what you buy with a new refrigerant identifier. If you're seeing more R-1234yf cars showing up at your shop, your first
steps are to get a new refrigerant identifier and then a recovery/recycle/recharge machine, either an R-1234yf-only that
meets SAE J2843; or R-1234yf/R-134a (SAE J3030) equipment for both refrigerants. We've covered both types of machines (in fact, even a reduced initial cost option, equipment
that starts out as R-134a capable and converts one time to
R-1234yf. Those investments make more sense than taking
"tampering" risks with R-134a vs. using R-1234yf. ■

tion is necessary. However, if one small can doesn't do the
job for a do-it-yourselfer, the price of a second can probably
would become an issue. And if there's a big enough leak so
any cooling is lost in short order, the customer would either
try sealer, or look for a professional to find and fix the leak,
or "give up" and switch the system to R-134a.
As an aside, we're no fan of small cans in this era of highlyaccurate recovery/recycle/recharge equipment needed for
professional service. But we're realistic enough to know that
many shops still use them, even some shops that have R-134a
recycling equipment. And with the new R-1234yf machines
and an R-1234yf market still building up, we wouldn't be
surprised if a lot of shops that use J2788 machines for R-134a
are waiting for a greater need before they get the R-1234yf
equipment (that meets SAE J2843 or J3030). So these shops
also represent an early market for the R-1234yf small cans
and taps.
Further, if you're equipped with R-1234yf R/R/R machines, the price of the "big" (10 lb) jugs is an issue. In midsummer, they were selling for $675, or $67.50/lb. We confidently predict that when we get to the off-season, we'll see
further drops, maybe even into the $50/lb. range or less. Assuming you can wait for winter, just shop around, carrying
a new hand-held identifier with you to verify the purchase.
That amount still is a lot more than the price of R-134a,
but remember this: the small can marketers are packaging
just eight ounces into the cans for a reason (beyond the yf
price factor). The system capacities have been coming down,

MORE THAN ONE ISSUE? WELL NOT REALLY
We repeatedly hear about systems that won't stay fixed,
or, "I found the problem, fixed it, and now it's back with another problem causing the same symptoms." With a complaint about poor cooling, even on a late model, there are often several issues that you'll find. Sometimes it comes down
to, "How much do I fix, and when do I consider the system
'fixed enough' to send the car out the door?"
That's the sign of a professional, someone who (most of
the time, anyway) can make a good "how much to fix" decision and knows when to send the car out. It usually comes
down to assessing the severity of a problem you find, and
how much it will take to fix it. If it's easy, but expensive (such
as an electronic control module replacement), and you can
make confirmation tests, you do it. If it's low-cost, you just
go ahead and do it. However, if it's not easy to confirm and
you're not positive you can confirm its value, you note it, tell
the customer, and explain that you've got the system working now, but the issue you didn't service could come back
to bite.
Here's an even worse case: you find a number of things,
fix them all (one after the other), and for some reason the
symptom (poor cooling) keeps resurfacing. That's why it's
good practice to document everything you can, every step of
the way; system pressures before and after a recharge, leaks
(where they were and how they were fixed) and A/C register temperatures each step of the way. For after all, if sup-

November 2017

posed performance fixes, such as a new switch, etc. didn't
produce demonstrable results in terms of A/C circuit operation, the arguments for doing the work aren't easy to make.
Here's a tough case that made every step one you might
later question. The vehicle: a 2009 Nissan Murano with the
3.5-liter V6 and Automatic Temperature Control.
There was poor cooling, and the system was low on R134a, and leakage was found at the compressor. The technician did a thorough system leak check to be sure that the
compressor was truly the issue, and he replaced it. With the
new compressor and a full refrigerant charge, the system
started to cool again, but after a while, he saw heavy frost
formation on the line from the evaporator to the low-side
service valve, which he confirmed was a sticking open expansion valve. So he replaced the expansion valve and the
frosting stopped.
However, the system performance was marginal. On a
90°F day with moderately high humidity, the air coming out
of the A/C registers is over 60°F. Now the technician has a
really tough decision to make; does he tell the customer that
this should be acceptable on a day with relative humidity of
just over 75%? Or does he look for more to fix? He verifies
that the HVAC case temperature doors are working normally, and that the system and the ATC sensors have not logged
any trouble codes.

MACS Service Reports

Table of Contents for the Digital Edition of MACS Monthly Newsletter - 2017