[pSun]

Hello,

My heater core has failed. I need to replace it immediately (28 degrees F last night, chance of SNOW tonight), I have the dash and defrost ducting out. I am uncertain what to do next and don't want to take apart more than necessary.

The Haynes suggests removing the 4 fasteners in the engine bay on the firewall and through PFM, simply removing the heater core.

From the illustrations in the manual, the heater core is to the driver side with the A/C condensor to the passenger side.

My guess for the next step is to take apart the remaining duct work until I locate the heater core and remove it. From what I have read on this forum there is more to this. I do see what appears to be a top and bottom to the duct work.

Help is welcome.

 

[Bob Lincoln]

John Wood has posted photos and text here before as to how to do it. You have to remove the heater box, which means evacuating the A/C, if equipped. Others have cut the heater box apart and glued it back together. I don't recommend that, too difficult to seal it, and it might produce rattles. It's said to be a full weekend job for the first-timer.

 

[pSun]

BobLincoln:

It did take me 2 days so far and I am not done yet. I had taken apart one of these dashes before for a friend, I knew it wouldn't be too pretty but I couldn't remember the conclusions I had drawn from the past effort. What I learned this time is that the seats need to come out, the dash must be unbolted but not completely disconnected. I unplugged everything on the passenger side, the heat/AC control station but over on the driver side, I only unplug what is needed to swing the whole dash over to the driver's side out of the way of the heater/AC housing.

Once the dash is swung to the driver's side, I unbolted the 4 fasteners in the engine bay (which hold the heater/AC housing in place). After that the housing is free of the firewall and there was plenty of room to work on it on the passenger side floor. I unbolted all the fasteners on the top and the 2 that are on the driver's side but are reached from the underside. The top popped off, the core slipped out; I installed the new insulating foam and slid in the new core, buttoned up the top piece and bolted back to the firewall (with my daughter guiding me, ready with anchor nuts, in the engine bay).

You may find it necessary to remove more of the dash to make all that happen. If you don't need to remove any of the ducting or wiring don't. If you find they interfere, remove only what is necessary as they are more of a pain to unbolt as their re-installment is worse than the whole job combined!

Unfortunantly for me, after tightening everything down, I found a short rubber hose lying on the floor where I was working. It is about 4-5 inches long with offset 90 ish degree bends on either end. I figure it is part of a drainage system for the housing. It doesn't appear to be the main drain as it doesn't fit that (the lower drain into the engine bay, passenger side). I figure I will be tearing this appart again very soon or as soon as the water starts to accumulate. If the rubber tube sound familiar to you please key me in to where it came from. I will have to drive this way until Saturday afternoon no matter what.

 

[Bob Lincoln]

Sounds like you did well on a tough job. The only hose I'm familiar with is the drain tube for the A/C condensation, and you say it's not that. So I don't know what else that can be. If you post a photo, someone should be able to identify it.

 

[pSun]

BobLIncoln:

-they say that the hardest part of going to the gym is getting there...I did have some motivational issues with this task, but, after having done it, it just wasn't as bad as I remember. Thanks for the kind words!

 

[phinxter]

I'm right in the middle of this job, did you have to remove the steering column or just lower it? I havent removed any seats not sure why you would have to unless the column is not low enough to get the dash over it and leave wires connected.

 

[pSun]

I removed the seats for 2 reasons: 1) it permitted me to lower the steering colume without needing to remove it (you don't want to disconnect the steering if you don't need to), 2) with the seats out, I swung the dash (still partially attached) to the driver's side, out of the way...while being able to swing the heater/AC housing to the passenger's side (while also partially attached); I did all the work right in the car on the passneger side. My seats come out pretty easy compared to fully removing the dash or the heater housing.

One thing to NOTE; to get the dash where I needed it, I did need to disconnect part of the air bag system ( the yellow wires in the center counsole). DO NOT HOOK THESE BACK UP WITH THE BATTERY CONNECTED!!! Ensure the negative battery terminal is disconnected prior to doing anything with the steering colume or it's associated "yellow caution" wiring!!! Also, ensure eveything is reenstalled and hooked up before reattaching the batteries ground. The Air resraint system is an explosive device!!!

 

[Bob Lincoln]

Did you have to discharge the A/C (move the evaporator) to get the heater core in and out?

My windshield is fogging and won't clear, is getting worse this week, and I smell rubber hose inside. I'm using about a pint of coolant a month now (1,500 miles). No leaks anywhere else. I must have a pinhole leak that's opening up. So I'll be doing this job on my 93 Daytona soon (or parking it for the winter, one or the other - no garage to work in).

 

[pSun]

BobLincoln: yes, the Air Conditioner had to be discharged, diassembled and removed from the firewall 1st to perform this proceedure.

My defroster worked better when used with the A/C, but it is cold here now and I can manage a modestly fogging car with a combination of a good pumping heater/rear defroster/ and "cracked open window" management! I am not planning on hooking the A/C system back up at this point. If I lived in Arizona I would be singing a different song.

Take care of the A/C as a separate job, as this will inhibit progress on the heater core. I had the A/C discharged, then removed it to the fire wall the week prior to the heater core job.

 

[phinxter]

@ pSun

The first thing I did was disconnect the battery, with all those sharp edges and wires I have run over the years there was no telling what was going to get pinched. Ok I'm going back at it today, thanks.

 

[Bob Lincoln]

Just checked the antifreeze, it's right where it was a few days ago. Driving mid-day with no frost, the windows did not fog up at all, even with heat on high. The slight rubbery smell persisted, I'm wondering if it's lingering from when I had the tires stored in the back for over a month while I fixed the brakes.

This car had mice in it when I bought it, and I pulled handfuls of hood insulation out of the evaporator fins. Maybe there's some blocking the defrost vents, even though I feel decent airflow.