MACS Service Reports - 2016 - JAN4

the coolant flow and were deposited in the heaters. Whatever the root cause, there's a lesson here.
The loss of both front and rear heat doesn't necessarily have an overarching issue with a single step
cure. And even in this case, although there was a
single fix, it had to be applied separately to each
area.

seepage from the upper radiator hose. This may not
even be easy to see, if the particular vehicle has a
cover over the ABS module at the right front, held
by push pin retainers.
If the hose is correctly located, the factory fix is
to add a second clamp, leaving the existing one in
place and positioning the new one just inboard between original clamp and the radiator itself.
There's something special about that clamp (Figure 6): it has a torque-limiting head, so it breaks
free when the 7 mm bolt head is tightened to the
spec of 26 lb. in. This clamp addition will probably be handled primarily under warranty, but the
principle of a torque-limited clamp does raise this
question about stopping small leaks from radiator
and heater hoses on all cars and light-duty trucks:
should you be using something similar or can an
ordinary worm-drive clamp do the job?
Our position is that heat shrink plastic bands are
as good as it gets. A heat gun will tighten the clamp
initially, and as the coolant warms up, the plastic
band tightens up to a safe limit that should prevent
a leak. Or if you want a worm-drive, there is a type
we also like: it includes a coil spring to maintain
tension in addition to the effect of the clamp itself.
And it can be removed and re-used if necessary
(Figure 7). ■

FACTORY FIXES

Paul Weissler

www.techauthority.com

The typical factory fix for a low-mileage coolant
leak is generally pretty straightforward. There's
often a new and improved gasket if it's from the
pump or stat housing, along with new bolts and a
specific tightening sequence. There's occasionally a
removal of a casting flash, perhaps replacement of
an o-ring or even a hose. And once in a while we
even see a new hose clamp. But because some of
today's hose clamps are often a crimp type, they
seem to perform very well and rarely give trouble.
In fact, with new hose joints and parts, the simple
spring band clamp also is very effective. Further,
hose necks typically have a molded-in stop, so
there's never a question of exactly where the hose
should be positioned for clamping.
However, we just encountered a new approach
to a factory fix in this area, for new Dodge Challengers with the high-performance (supercharged)
6.2-liter V8, when there's a small amount of coolant

Figure 6: Special hose clamp used by Chrysler as a field fix goes on, just inboard of the existing clamp, which remains in place; the two provide the seal.
The additional clamp is a torque-limited type that "breaks away" when the
pre-determined torque is reached. Top illustration shows clamp before torque
is applied; Lower illustration shows clamp after torque limit is reached. Notice
tongue of clamp at upper right (A) and bolt is turned flat (B) against the head
of the clamp.

January 2016

Figure 7: This worm-drive clamp includes a coil spring to maintain constant tension. It's an excellent type of premium design for problem hose
sealing applications.

MACS Service Reports

http://www.techauthority.com

Table of Contents for the Digital Edition of MACS Service Reports - 2016