ascMcLaren Enthusiasts

bryan · Joined: 30 Aug 2004 Posts: 143 Location: Atlanta, GA

Anyone ever replace their heater core without discharging the A/C system?

I have an old Mustang Monthly article that I got online that walks you through the tricks to doing it, but I'm still not sure whether or not I should just replace the evaporator core while I'm at it. A/C blows cold and still has R12, so I'm inclined to say "if it ain't broke don't fix it." I've never had the evaporator fail in my cars, but...

Not looking forward to this job Unhappy

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'87 Guards Red ascMcLaren (#398)

jscheller · Joined: 03 Sep 2004 Posts: 11

I have, and it still wasn't fun. After removal of the entire dash, you will clearly see where the heater core sits in the blower box by the way it is molded around it. I just took a Rotozip and cut out the blower box around the heater core which allowed me to pull the heater core straight out. After I replaced the heater core, I sealed and epoxied the section of the blower box I had removed. Then reassembled the dash and I was all set.

If I HAD to do it again I would go the same route because I don't want to discharge my R12 either.

negusm · Posted: Thu Dec 09, 2004 1:38 pm Post subject:

You do NOT need to cut up your heater box to remove the heater core.

You can also do it without discharging your AC.

Here is a very good guide:
http://www.50stangs.com/techarticles/heatercore.html

Please note, two things to make life easier:
1. You need to remove your seats.
2. You need to unbolt your steering column and let it drop to the floor. Make sure you disconnect all electrical connections before you do it.

You don't have to completely remove the dash but you will need to disconnect enough stuff to get enough room to get at the heater box.

-Mike
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1985 ascMcLaren Coupe - Midnight Blue
Under Restoration

negusm · Posted: Thu Dec 09, 2004 9:21 pm Post subject:

One more thing, if you do decide to disconnect your AC, then to remove the evaporator on 85-86 cars, you will need to remove the dash, pull the heater box almost all the way out, cut the heater around the markings which will let you finally replace the evaporator.

On 84 or earlier heater boxes, the whole thing can be disassembled and the AC evaporator removed. On the 85-86+ boxes, the unit is sealed (glued) together and cannot be dissasembled....hence the reason you have to cut the evaporator out.

In both cases the heater core can be accessed by unbolting the top flap.

I used the 84 heater box out of the donor car, disassembled it and put my 85 evaporator in it with a new heater core. The evaporator doesn't usually go bad (I think...it doesn't channel that nasty corroding coolant). The one in the 85 looked better than the 84 as a rodent had nested in the heater box.

-Mike
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1985 ascMcLaren Coupe - Midnight Blue
Under Restoration

svo413 · Posted: Thu Dec 09, 2004 9:41 pm Post subject: Heater core

FYI... Don't laugh at this one. I hear it is easier to get to if the windshield is out. Keep this in mind if you have to do both jobs (heater core and winshield).
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Kevin Gold card MCA Judge for Fox Body
85 ASC Vert #612205
88 ASC Vert #542 20,550 miles
84 SVO 24,000 miles, 84 GT Turbo Vert.
03 Mach I, 89 LX Vert, 74 Mustang II
14 CA Special, 69 Mustang coupe, 07 GT500
67 T-bird, 15 F150 Tuscany, 16 F250

negusm · Posted: Thu Dec 09, 2004 9:44 pm Post subject: Re: Heater core

bryan · Joined: 30 Aug 2004 Posts: 143 Location: Atlanta, GA

Thanks for all the advice, everyone. I think I'm just going to do the heater core and leave the ac alone. I've replaced a heater core on an 88 mustang I used to own, so I know enough to realize it's not going to be fun. I appreciate the pointers.
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'87 Guards Red ascMcLaren (#398)