MACS Monthly Newsletter - 2017 - MAY2

Coolant Chemistry Debates

and Peak Global OAT do NOT use 2-EH. Besides 2-EH
found in some OAT / DEX-COOL ® coolants, air was
determined to be a major factor in causing system breakdowns. If those formulas weren't enough, Phosphated
Organic Acid Technology (POAT) came into the market
in 2008 in newer Mazda engines made for Ford in a dark
green color.
Which coolant do you use? OEM recommended? Universal? Personally, I go with the OEM unless there is a
compelling reason not to. What would a compelling reason be to NOT follow OEM recommendations? Budget
limitations for select customers and vehicles would be
the primary reason in my opinion. If the customer hasn't
had any problems (yet) with their cooling system AND
they are on a very tight budget, AND they are willing to
change that 'universal' coolant on a recommend interval
based on the shop's experience, AND they don't plan to
try to squeak out 200K to 300K miles from their vehicle,
many of us who have the task of keeping customers happy will do our best to appease them without going overboard on cheap.
The old saying 'sometimes cheap is expensive' frequently can be applied. It boils down to putting best
practices first to protect your customer's vehicle and
your good name. (Not to mention your warranty.) When
trying to stay competitive with PM services such as coolant exchange / flushes it's often a minority of shops that
stubbornly stick to OEM standards regarding the coolant
choices.

Much has been written regarding the different types of
coolants such as OAT, HOAT, and POAT along with the
concerns of chemical reactions with cooling systems regarding the use of phosphates and silicates. The debate
continues on in the service sector in regards to whether
the OEM coolant formulas really do make a difference
compared to the "universal" coolants that many shops
and DIY folks use.

Coolant Chemistry Review
Ethylene glycol (EG for short) was green back when I
was a young tech. That formula used way back then is
fairly obsolete now. That original green colored antifreeze
went by the technical name Inorganic Additive Technology. (IAT) The old green antifreeze contained Borates,
Phosphates and Silicates. Silicates (think sand) can drop
out of the coolant mix and become abrasive causing leaks
and worn out water pump impellers. When air (from low
levels) mixed in with the coolant (cavitation) and sharp
bends in the cooling system were present, the velocity of
the silicates in the coolant could at times cause the abrasive damage to happen in a very short time. Reports of
new heater cores beginning to leak after a few hours of
run time were not urban legends. The cavitation / abrasive effect acted like a sand blaster. When you changed
the old green IAT regularly, there were very few problems. The original green IAT had decent corrosion protection in the form of additives but those additives did wear
out.
Organic Acid Technology (OAT) became common with
DEX-COOL ® which became the required coolant for GM
and a few other manufacturers starting in 1996 as the
5 year / 150,000 mile coolant. Often called "Long Life"
or "Extended Life" coolant OAT gives a properly maintained vehicle's coolant a long service life mainly due to
the increased longevity of the coolant's additives. The
OAT formula never became the panacea of OEM coolants. Chrysler, Ford, Mercedes and some others recommend not using OAT / DEX-COOL ® coolant in their late
model vehicles. HOAT (Hybrid Organic Acid Technology) a.k.a. G-05 ® is used by those OEMs. Studying the
back of a Zerex coolant bottle will give you the notion
that a simple color coding system exists for coolant; green
for the old Ethylene Glycol IAT, (conventional short life
anti-freeze) orange for OAT (GM DEX-COOL ®) and yellow for the HOAT EG. While this may be true for some
brands of coolants, it is not an official standard. Coolant
makers can use whatever color of dye they like. HOAT
can come in blue, pink, orange and even green on some
Chrysler products. While HOAT EG does contain some
silicates, the amount is less than its predecessor - the old
conventional green IAT* OAT / GM DEX-COOL ® had a
very rough road in the first few years. OAT / DEX-COOL
® contains ethylhexanoic acid (2-EH) as a corrosive inhibitor. 2-EH is prone to damage plastics like Nylon 66
used in intake manifold gaskets and radiators. G30 OAT

May 2017

Water, Water Everywhere - and Opinions on it Too!
The antifreeze is only ½ of the coolant equation. What
about the water? A missing element in information regarding coolant, in my opinion, is the available information on that topic. Most if not all MACS readers know
that tap water is not universally recommended by vehicle
manufacturers to mix with full strength coolant in today's
cooling systems. In my travels throughout the country
teaching technical update classes for professional technicians it has become apparent to me that the consensus is
divided into three main camps on the subject of the water
used in coolant:
PREMIX - Just buy the premix and save yourself the
time and hassle.
YOU MIX With Distilled Water - Buy full strength coolant and do the 50/50 mix yourself but use distilled water.
YOU MIX With Tap Water - You go ahead and use the
full strength coolant mixed with tap water as long as you
are on a city water source - not a well.
I'll take a shot at all three of these approaches by first
saying the proverbial "if it's not broke, don't fix it!" What
I mean by that is if you are having great results with any
of the three aforementioned approaches to coolant (no
customer complaints / comebacks) then you might rightfully ask "why change my approach?" However keep
these facts in mind if you do see an occasional comeback

MACS Service Reports

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