MACS Monthly Newsletter - 2020 - DEC2

December 2020

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And still more to think about: Turbos benefit from lots of airflow, so blockage from grille covers of any kind may be of questionable value, from that standpoint.

Figure 3: PTC (positive temperature coefficient) heaters
such as this one shown are a durability improvement over
a conventional resistance heater. If the battery condition is
good, turning on the PTC heater produces immediate cabin
warmth. The PTC heater runs at lower temperature than
a conventional resistance heater, so it provides longer life.

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ing pebbles and small rocks. Grille guards that are intended to
block airflow through the front-end heat exchangers to conserve
coolant heat for cabin warmth are still available. They're called
winterfronts, and are used on trucks, particularly diesels, operating in very cold areas, and occasionally are even recommended
for some cars (Figure 1). Of course, no car maker installs or offers
a winterfront or grille guard as original equipment. It not only
would add cost without necessarily increasing customer satisfaction but could imply that the heating system isn't adequate.
Further, if left in place, in hot weather it could cause overheating.
In addition, if the motorist decides to tow a trailer with the grille
cover in place, it could overheat transmission oil and result in
transmission damage. With all these factors, it makes sense for
the car manufacturer to be very cautious about any installation
of a winterfront. So, you can understand why the OE approach
is to address specific heating complaints, which may turn out to
be just a handful.
Further, so many cars and trucks are now being equipped
with active grille shutters. Which although designed to close for
improved aero and fuel economy, they also may have thermal
controls to close them for better heating. Even those grille shutter
systems without active thermal control typically are designed to
close on cold starts.
Where an ultra-low ambient heating problem is apparent,
there may be exceptions among lower-priced economy cars.
One group are from General Motors--the Chevy Cruze, Sonic,
Spark and Trax, and Buick Encore with the 1.8-liter and 1.4-liter (this one turbocharged) four-cylinder engines and the new
three cylinder (for two subcompact crossovers, a 1.2-liter for the
newly-introduced Encore GX front-drive and a 1.3-liter version
for the Encore GX AllWheel-Drive and forthcoming Chevy Trailblazer). However, the
grille cover installations
are retrofits, and were
recommended only for
the 1.4-liter four-cylinder
turbocharged
Encore
and Trax. And that grille
cover is a specific design
Figure 2: This grille cover, for new for those cars. Further,
Buick Encore and Chevy Trax, fits General Motors says to
over just one section of front-end expect no more than a
airflow openings. It's designed to modest improvement in
provide a modest improvement in cabin heating from the
heating without the possibility of installation. If you look
overheating, particularly transmis- at the grille cover setup
sion oil, if loads are carried or towed on the Encore and Trax
(Figure 2), you'll notice
on warm winter days.
that it covers only one
part of the front-end air
intake (which helps explain its limited effect). That is undoubtedly attributable to the GM cautious approach, and something
you should keep in mind when considering front end grille coverings.

Figure 4: Labeled 2a on the drawing, this PTC heater slides out
of HVAC case of Jeep Renegade as illustrated. The two relays that
are the heart of the circuitry are just below the opening for the PTC
heater.
However, if the weather is really cold, and the engine never
gets quite warm enough (long an issue on many small Japanese engines), the simple installation of a sheet of cardboard at
the front of the cooling module should provide some benefit -
something that veteran technicians have known (and done) for
eons. Just tell the motorist that this is a for-winter-only move, not
to tow with it in place, and the cardboard, or winterfront / grille

MACS Service Reports

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MACS Monthly Newsletter - 2020

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