HOLDEN WN CAPRICE 2014 Owner's Handbook Manual page 256

9-48 Driving and Operating
The Holden Genuine Accessories
are an exception, however they
should be removed in high load and
high temperature conditions.
Caution
In high load and high temperature
applications (e.g. towing) no
objects should be fitted over the
upper or lower air intake at the
front of the vehicle, as this could
affect cooling. This includes
removing Holden Genuine
Accessories in this area, in these
conditions.