Contributed By: Rob
Mcpheeters
Having attempted to use the Haynes manual to remove and make repairs to my
heater core, I'd like to supplement the existing material with first hand
knowledge.
While the Haynes manual does properly outline the procedure, there are a
couple of additional things the STM (shade tree mechanic) can do that will
greatly improve the process.
While all of the steps mentioning the under the hood procedures are sound,
I would only add that the STM be very careful when removing the heater hoses
from the input/output necks on the heater core itself. These are a
fairly thin gauge copper and should be treated respectfully. My heater
hoses were old and had resultantly "welded" themselves to the
flanges. A steady, strong back and forth twisting motion should be used.
No attempts should be made to use screwdrivers, et al as this may result in
the damaging or puncture of the input/output flanges necessitating heater core
replacement.
As my vehicle is also equipped with air conditioning, I found it very
helpful when working from the interior to drop the entire AC motor and duct
assembly from beneath the dash when trying to access the two internal
mounting bolts for the heater box assembly.
After lowering the AC assembly, it should be noted that there are two bolts
that can easily be mistaken (trust me!) for the intended nuts that need to be
removed. The two bolts I mistook mounted the heater duct work to the
internal side of the firewall. But as the pictures in the manual are
somewhat ambiguous, I didn't find out until after taking them out.
The two correct nuts are directly in line with each other vertically and
are about 12" in from the passenger door. The lower nut is easy,
but the upper nut is a little misleading because it sits a top the vertical
mounting bracket for the AC fan motor housing support. You must remove
this nut, THEN remove the AC mounting bar, THEN the nut closest to the
firewall is what you're looking for. After its removal, the heater box
came away very easily.
This sounds far more complicated and troublesome than it actually is.
In reality, it would take no more than twenty minutes or so to drop the AC,
remove the intended bolts (internal and external) and get everything back
together.
