MACS Monthly Newsletter - 2022 - MAR8

Motor/electronics liquid
cooling system service
The weak link in the Motor/Electronics cooling
You will find liquid cooling on every heavier Hybrid
or EV that is on the road.
Think about the heat generated by:
-Motor/Generators propelling a vehicle
-Motor/Generators charging an HV battery
-Plug-in charging an HV Battery
-Charging during regenerative braking
-Transistor controls for the drive motors
-Transistor controls during regenerative braking
-Powering a 3-phase A/C compressor
-Powering the 12-volt system
Note that the 12-volt system also usually provides
the boost for braking and the power assist for the
steering, which originates in the HV battery.
This quantity of heat cannot be radiated into the
air efficiently, even using heat sinks, so a liquid cooling
system is used for the required capacity.
system are the spring-type hose clamps and the
electric circulation pump. Here in Ontario, Canada
we have been seeing tow-ins for a couple of years
only caused by rusted spring clamps.
I cannot stress it enough in areas that use salt
on the roads during the winter, check these hose
clamps when the vehicle comes into your bay for
service. It can take up to a few hours to change out
all the clamps, with the occasional HV component
having to be moved out of the way. Do not forget
the coolant lines to the CAT and rear heater if applicable,
which are usually under plastic covers with
plastic T-fittings for even more fun. Figure 9 shows
the rear heater clamps we replaced on a 2011 Highlander
in early January.
Stay tuned for Part 2 of this article and visit our
website at www.theautoprof.com to explore our Hybrid/EV
training classes and other resources. v
Figure 9: 2011 Toyota Highlander rear heater clamp corrosion.
MACS Service Reports is published monthly by the Mobile Air Climate
Systems Association. It is distributed to members of MACS and
is intended for the educational use of members of the automotive air
conditioning service and repair industry. Suggestions for articles will
be considered for publication, however, MACS reserves the right to
choose and edit all submissions.
Unless otherwise noted, all photos/art by author.
March 2022
8
Editor:
Production Designer:
Steve Schaeber
Laina Forcey
Manager of Service Training: Steve Schaeber
Mobile Air Climate Systems Association
P.O. Box 88, Lansdale, PA 19446
Phone: (215) 631-7020 * Fax: (215) 631-7017
Email: membership@macsmobileairclimate.org
Website: www.macsmobileairclimate.org
MACS Service Reports
Mike Bailey
http://www.theautoprof.com http://www.macsmobileairclimate.org
MACS Monthly Newsletter - 2022

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