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Heater Core Removal

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.

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