advice for heater core r&r

David Conner conner at
Mon Mar 17 10:42:00 EST 2003

There is a thread on this subject dated Jan 20 1998.  Part of it is copied
at the end of this e-mail.

You must disassemble the blower box to replace the heater core.  The
trickiest part for me was getting the flaps back in the correct
orientation.  There are five of them... carefully mark their positions
before pulling the box apart.  The idea suggested below for reassembly
would be a good thing to try.  Bentley describes this process somewhere...
I think it's buried somewhere in the air conditioning section.  They
describe a special tool (a jig) for getting the flaps back in their correct
orientation.  You won't have this jig, hence the importance of noting flap
positions prior to disassembly.  You might try making a jig from cardboard.
 Also, there is one deeply recessed screw that is too deep for a normal
philips screwdriver.  An extra long one can be found at Home Depot.  While
you are at Home Depot, check out their metal/foil duct tape.  It's
excellent stuff, much better than regular duct tape... just the thing for
sealing the two haves of the blower box back together.

Before pulling the blower box you need to drain some coolant from a
radiator hose in order to lower the coolant level so it doesn't flood into
the blower box area and interior of the car.

If you are able, you may want to get a new seal for sealing the blower box
to the body.  This may be dealer only, but I don't think it's very
expensive,   It would also be good to have some foam tape weather strip on
hand for where the blower box butts up against the interior ductwork.  You
will also need to seal the heater core to the blower box with silicone/RTV.

As to the amount of time to plan on spending... I'd say it's an all day
affair.  The most time consuming parts for me were the struggle to get the
box out of the car, and reassembling the box with all flaps properly
oriented.  Be careful when prying the box free that you don't damage the
A/C line running along the top of the firewall.
Dave C.


Re: Help with heater core replacement-'87 5kTQ

    To: Tony Lum <tlum at>
    Subject: Re: Help with heater core replacement-'87 5kTQ
    From: four.rings at
    Date: Tue, 20 Jan 1998 09:32:11 -0500
    Cc: quattro at

Tony Lum wrote:
> Hi gang,
> I'm trying to replace the core in my heater box assembly.  Getting the
> assembly out of the car wasn't too bad, but getting the box apart has been
> a royal PITA.  I've removed the clips all around and the two deep screws in
> the recess in the middle of the assembly, but it still won't split apart.

Two more recessed screws left.

> Is there a trick to this or should I continue to nurse it apart?  Do you
> really have to dismantle all the flap levers?

Yes. For their assembly back together:
1. drill 5mm deep ~2mm DIA holes in the flap's axles.
2. cut 10cm pieces of coat hanger wire.
3. stick those pieces into the flap axles.
4. fish the wire through first, when assembling the halves of the box.

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