MACS Monthly Newsletter - 2017 - JUN1

Total Vehicle Climate and Thermal ManagementTM

June 2017

By Dave Hobbs - MACS Field Correspondent

Tech Service Bulletin: Nasty Oil Stains Mean Compressor Leak? Maybe Not!
pressor Module or ACCM for short. According to GM,
a very minor amount of weepage of refrigerant / oil at
the compressor seals may actually not lower the charge
significantly enough to reduce performance but none the
less still create some very nasty looking oil stains on the
electric compressor. Keep in mind that the seals on electric compressors are case seals and not shaft seals as with
belt driven compressors. GM further advises to use dish
soap and water if you want to clean up the ACCM but
NOT to use harsh chemicals (engine degreasers, brake
cleaners, etc.) to prevent those chemicals from damaging
the seals and actually creating a full blown compressor
seal problem that will leave your customer with an A/C
cooling performance complaint. ■
Photos Courtesy General Motors

General Motors released a Preliminary Information
bulletin (PI) #16-NA-192 dealing with what looks like an
obvious refrigerant leak on their 2014-17 hybrid passenger cars. Those models include the Cadillac CT6 along
with the Malibu, Volt, and Spark EV wearing the Chevy
bowtie. On these models, heavy stains (Figs. 1 & 2) on
the electric compressor which are from refrigerant oil
may not be an active leak as it might appear. Techs are
advised to first verify if there is a customer complaint for
A/C cooling or low refrigerant charge present. If the customer is fine and the charge is right, test for an active leak
using a R-1234yf compatible (SAE J-2791) electronic leak
detector. GM refers to the electric compressor on these
HEVs and EVs as the Hybrid Air Conditioning Com-

Figures 1 and 2: These photos of GM's electric compressors (ACCM) from some of their late model HEV (Hybrid) and EV (Electric) vehicles would normally create a
'oh now I see the problem' moment in diagnostics due to the amount of refrigerant oil stains (refer to arrows) on the compressor housings. GM advises that the stains
may be from normal seal weepage and will not create an A/C cooling complaint.

ALSO INSIDE THIS ISSUE:
PTCs Electric Heaters - Not Just for hybrid Vehicles! .................................................................................................. 2
Ford Tech Service Bulletin - Blower Motor Electronic Woes from Battery Problems ................................................ 4
Battery Drain Diagnostics - Revised and Updated! ....................................................................................................... 4
EASY Test Tip for Identifying Parasitic Battery Drains - With an Ohmmeter! ............................................................. 7

MACS Service Reports is the official technical publication of the Mobile Air Conditioning Society Worldwide, Inc., P.O. Box 88, Lansdale, PA 19446. The material published in MACS Service Reports expresses the views of the contributors
and not necessarily that of MACS. Every attempt has been made to ensure

June 2017

the accuracy of the content of MACS Service Reports. MACS, however, will
not be responsible for the accuracy of the information published nor will MACS
Worldwide be liable in any way for injury, labor, parts or other expenses resulting
from the use of information appearing in MACS Service Reports.

MACS Service Reports

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