Hardbody heater cores are not fun to replace.

[HRH]

So has anyone else had the fun that is the annoying hardbody dash? I preferred my old method for heater core removal on Ford Taurases at the wrecking yard. Zip nuts off firewall, zip basic nuts of front of dash, insert 5 foot bar through windshield and dash. Yank. Nothing like a 15 minute heater core!

 

Alas, this is a customer's car, and he's a very nice fellow. I put a heater core in a year ago and the f***er has started leaking. Not small either, just dumping fluid, not the hoses, and even if it was, I'd still have to yank the box to get at them. So I've been doing a little each night.

 

This is the problem with engineers. They need to think about where all their shit ends up. They never do. Case in point, the ONE nut you can't reach unless the dash is gone. They could have made a notch in the ducting tube so it could have been reached from the front, then made the heater suitcase just a little smaller so it could be detached and yanked out via the glovebox, but no. They just hid everything right smack dab in the middle. If I ever design a car, my heater core will be mounted in the engine compartment on the firewall and will be easy enough to change out in 10 minutes. A little longer ducting on the inside wouldn't hurt a bit. Easily doable.

 

Anyway, in case you haven't ever had the pleasure of a D21 heater core going out, here are some pictures to see what you're missing! And 86.5 hardbody dashes are VERY brittle. I broke out most of the vents on this truck the last time I did the heater core, fortunately it's a winter beater. And even now, being careful, I touch a screw or bolt and plastic starts cracking off. Horrible. Going to have to silicone in a few parts.

 

 

 

 

 

[HRH]

Round two, I have a video uploading to youtube as I type. Can't find the leak in the heater core, it's annoying me a great deal.

 

EDIT: I got Buddy to come out and take a look, and I've yanked all over this thing, but he pushes right at the plastic housing where the valve is, and instant spurt! :D Good to have a fresh set of eyes on something. I moved all the tubes, but hadn't pushed hard enough on the plastic piece.

 

Now to make sure the new heater core isn't going to do the same thing.

 

[HRH]

And here lies the root of the problem. Sadly, the correct heater core is not from NAPA. :( However, given the old boxes I've gotten, I would imagine I managed to get the last two of the old line of heater cores. I could be mistaken. Anyway, took a trip up to the competition and bought theirs. You have to admit when you're licked, and 4-5 hours of heater core fun, I'm not taking a chance on the other "new" one failing.

 

I will say the heater core is solid, it doesn't leak unless the inlet is tweaked. And anyone who has replaced a heater core knows that even a factory unit is hard to get absolutely zero stress on the inlets and outlets. Rubber just isn't that forgiving.

 

 

 

EDIT: This one didn't work either, see below.

[HRH]

Well, my good fortune seems to have been short lived. Just put in the new improved heater core and the fucker still leaks. On the phone with Nissan right now to see if OE heater cores still exist.

[HRH]

So the next thing I'm going to try is the other NAPA version I have. I think this one I may rtv the piss out of to prevent leakage. Doesn't seem to matter how nice I make the attachments, the shit just wants to leak. Super pissed, returned the defective heater core to O'Reillys, that went over well since I was still wearing my NAPA beanie! :rolleyes:

 

Anyway, thoroughly cranky now, going to eat some dinner and calm down, then go another round and see if I can get these things to stop leaking. Whose idea was it to put a blend unit on the heater core?! Fucking engineers! If I can't get this to work, I'm getting a 720 heater core and running a mix valve in the heater hose in the engine compartment.

[HRH]

Ok, here's what we've been up to the last few hours. After vegging on the couch contemplating, came up with the rtv solution for having the thing back in the truck and leak tested tonight.

 

 

 

 

 

 

 

[nismo dr]

looks like you average nissan heater core job, now get done and find out warranty deemed that a 2.5 hr job :blink:

[HRH]

I didn't look up the book hours, but I'm told it's a 4-5 hour job. Either way, I've lost my ass on it many times over with all this dicking around. Fortunately I'm just wasting my weekend. Get to go to work tomorrow, oh joy! And it's been raining all day. I may have puddles to navigate tomorrow morning. Already have a lake in front of my garage. I just wish this would have been a normal Nissan heater core, with two outlets and a valve separately mounted somewhere else.

[68Datsun510]

All the more reason i want to get rid of mine, good GOD thats a nightmare! I have a 97 and it CANT be easier!

[HRH]

It's slightly different, you have the new dash. Keep in mind though, this heater core only went on the 86.5 D21 at 189k and 24.5 years later. So really, it's not that bad. I love my hardbody. And it's still easier to work on than a cramped new V8 stuck halfway under the cowl.

[Pacific coast Datsun]

Holy hell what a hassle & all over a 10 cent O ring ? I own a 94 & ive had the dash out twice for painting [my choice] & i hope my heater core never gives up on me :rolleyes:

[HRH]

Alrighty Nismo, I think you're more accurate on that 2.5 hour time. Now that I've done it twice, I got it back together a lot easier. Still, add 1 hour for delicacy to not break all the dash vents and other brittle plastic. Anyway, truck is back in working order and back at Ray's. Drove it all the way back with heater on full, no leaks! RTV is definitely the way to go on that plastic inlet/mixing valve.

[nismo dr]

Doing it a few times definably speeds it up. We were doing a ton of B15 Sentra heater boxes a few years ago, one guy would take driver side the other passenger and have the dash and heater box out in 20-30 min

[Creepy Cruiser]

Wow, I'm sorry Matt. I wish you would have called me, i could have told you how to do it without removing the dash at all and do the whole thing in about an hour. O'well, you're good at it now, lol.

[HRH]

Wait, what?! :blink: Actually, I thought about alternate engineering it. I could technically cut off the mounting tab on the top where the nut is hidden behind the ducting, but even then there isn't wiggle room to slide the box out. If there was more room behind the engine, I could have cut a rectangle in the firewall, and drug it out that way, but I'm pretty sure it wouldn't clear.

 

I had many an evil Spaldings-induced thought about removal. :D Hell, my first hardbody had 2" holes at the footwells because I didn't have an extension long enough to get the top two bellhousing bolts. So a holesaw later, TONS of room! Except I never put plugs back in the holes, that poor truck probably has rotted out by now.

[Creepy Cruiser]

Yep, If you just remove all the bolts that hold the dash in place, and remove the cluster, you can pull the dash away from the firewall far enough to pull the heater out (without removing the dash). It's tight, but it comes out no problem. You don't have to unplug the harness or anything, just the cluster. I can't remember how I got to that rear bolt, but I do remember it being a bitch, lol. Most people just cut it off like you said. Like I said, it took a little over an hour to do the swap. I swapped in one from an early 90's, and it works way better than the original '87.

[HRH]

Not bad Todd! It's not really all that much more work to take the dash out, plus I like to inspect everything anyway, but interesting to know it can be weaseled! I'd really just like to make an external heater core. They should do all heater cores in the engine compartment. That would be so much easier for such an annoying yet important part. The old chevy's had the blower motors in the engine bay, why not the whole heater core too, you know?

[Creepy Cruiser]

Nope, I shave the firewalls on all my cars, so no thank you, I don't want then in the engine compartment, lol. My Hearse had the whole heater core and blower in the engine compartment, (before I shaved it all, lol) and it wasn't any easier to change the core in that one either. Now I'm trying to find a place for a core under the dash, lol. Nobody it ever happy.

 

So much nicer when it's all so smooth.

 

[HRH]

That's funny, I never noticed the skulls on the firewall before. Maybe we can make a million retrofitting heater cores? I know, put them on the roof! :D