Looking for tips on how to approach getting to the heater core on my '72 Z

[Coastalman]

My 1972 Z has the dealer installed AC. I know I can just start taking things apart, but if any of the forum members have some helpful tips on how to approach this I would be most thankful. I know I have a leak, but, at this time, don't know if it is the core or one of the hoses. As far as I know, this one owner car, before I bought it last year, has not had anyone try to get to the heater since the car was new.

Thanks,

Charlie

[Patcon]

Charlie,

I can't tell you exactly because its been a while since I disassembled one, but I believe the after market evaporator is in the way of getting to the heater core. Not an easy job and gets harder as I get older...

Charles

[Coastalman]

I agree. At 67 it is not easy to get under the dash and do the work I used to do on my first Z car back in the late 1970s. I am going to try and see how far I can get into this project before I have to take it to my local mechanic. It would be great if I could get to the leak myself. I'll see.

Charlie

[Zed Head]

I would pull the glove box first and get a good light in on the hoses. If it's just hoses then you can pull the heater fan and its motor and do that work instead of messing with the heater core. MY 76 still had the original hoses and they were almost porous. No actual big leaks, they just seeped coolant through the pores that had opened up.

[siteunseen]

Here's a thread that'll have some info. Starts at #12, http://www.classiczcars.com/forums/check-out-my-ride/52534-my-new-baby-72-240z.html

Likely the heater valve's leaking. Still available from Nissan. #32 has some tips on getting to it. Have fun!

Edited October 22, 2014 by siteunseen

[Captain Obvious]

At 67 it is not easy to get under the dash and do the work I used to do on my first Z car back in the late 1970s.

I was originally going to suggest that it's easier to pull the whole dash first. If you've got small hands and are part contortionist it's not "really" necessary, but I've found the extra time I spent pulling the dash was more than made up for by the ease of working on the heater system after I had done so.

No matter how you look at it, pulling the heater core out is a PITA. I feel for ya Charlie. Be careful of your back.

[sdyck]

Hey Coastal Man, I have the same set up and will be pulling it all this winter. Please take pictures and let us know your process. Neither my aircon or heat works right now. I intend to delete the aircon and fix the heater.

[Namerow]

I went thru the steps to pull the heater/blower assy in my '70 Z last year. Although I was able to remove them successfully w/o pulling the dash, I eventually decided to do that too... so I now have experience with both strategies and will offer these comments:

1. I you decide not to pull the dash, you'll need to remove both the glovebox liner and the HVAC controls faceplate in order to gain the access you'll need to get the heater and blower out. Many steps along the way require a lot of contortion and will favor agility, small hands, good lighting, and a lot of patience. You'll need to detach the heater control cables from the heater/blower assy. The cable clamp on the water valve could be problematic if there's been long-term leakage. The water valve may be seized, leaking, or both.

2. Removal of the glovebox liner is not an intuitive process, nor do there seem to be any good step-by-step instructions or photos available to guide you (incl. the FSM). It will not come out from the back (there's stuff in the way). It will only come out from the front. IIRC, I had to bow in the top edge first, and then bow in both sides. Eventually, if you bow in all 4 edges sufficiently, they corners will clear the opening in the dash by just enough to pull the liner out. If you're lucky, it won't tear or crumble in the process and might even be reusable.

3. Once you've got everything freed up, the heater box assy can be pulled out from the passenger side (best to pull the blower assy first, as a separate unit -- caution: it may be stuck where it mates up against the cowl panel). Be sure you put down some newspaper on the pssgr-side floorboard, because you're going to spill coolant when you detach the heater hoses and when you pull out the heater box.

4. When all is said and done, you may wish that you'd just pulled the dash first. It might just end up taking the same amount of time overall and it sure makes getting to the heater and blower a lot easier (for both removal and reinstallation). Also might make removal of the glovebox liner unnecessary (not sure about this -- maybe someone else can comment). Pulling the dash will also give you an opportunity to inspect and clean some key wiring harness connectors and replace all of the gauge lights (v. difficult to do with the dash in place, and nearly impossible for speedo and tach if your dash has a cap installed).

Let us know what you decide to do.

[Stanley]

Removing the evaporator was easy and made it easier to work in that area. My heater valve is all corroded and the hose connections leaked until I plugged the engine fittings. Need to replace the valve and hoses; not happy about that.

[Carl Beck]

4. When all is said and done, you may wish that you'd just pulled the dash first. It might just end up taking the same amount of time overall and it sure makes getting to the heater and blower a lot easier (for both removal and reinstallation). Also might make removal of the glovebox liner unnecessary (not sure about this -- maybe someone else can comment). Pulling the dash will also give you an opportunity to inspect and clean some key wiring harness connectors and replace all of the gauge lights (v. difficult to do with the dash in place, and nearly impossible for speedo and tach if your dash has a cap installed).

I would recommend Option #4. If you have one person to help - pulling the dash is really a far easier and better way to go. Trust me - this is not something you want to do upside-down cramped up under the dash. Even if you take the passenger seat out, so you can get under there - It is no fun when you are 25 and shear frustration when you are 65+. Pull the dash, do a complete "refresh" job on everything under there - Do it all once and be done. Hire a young helper.. maybe you can find a local Z Car enthusiast near you.

FWIW,

Carl B. pushing 70...

[metalmonkey47]

I would investigate a little further before attempting to pull it. When I bought my car from the PO, it still had factory looking braided hoses on the heater core and heater valve. The hoses were cut off at the firewall and the heater was bypassed. Although the hoses looked okay from the outside, I obviously still cut em out and replaced them. When I pulled it all apart I found that the heater valve was corroded and nasty. I assumed that's where the leak originated that had them cutting the heater hoses. I'm not one to throw out possibly good parts without testing them, so I cleaned it up with some steel wool until it looked presentable again, ordered some hoses from MSA, and finally put it all back together last night, expecting the 40 year old core to leak, or the valve to spray, but after running 30 minutes at temp not a sign of the slightest leak.

I guess what I'm trying to get at, is be sure that's your issue before ripping it apart. You can buy UV dyes, rent radiator pressure testers (P/N 9300 at Autozone iirc) that will help you verify your leak before gutting the car to get to the core.

I'm 23 and I was NOT looking forward to pulling my heater core out... Thankfully I didn't have to...yet. Datsun trucks are far easier then the cars.

[Namerow]

Metalmonkey47 makes a good point. I found that the heater valve ('water ****' in Datsun-ese) in my Z was frozen solid at the main pivot point of its linkage. This apparently frustrated the previous owner to the point where he/she forced the 'TEMP' control lever so hard that it bent the control cable. I simply soaked the heater valve in water-based parts cleaner for a week, then cleaned and lubricated the linkage and put a drop of Armorall on the valve's push-pull shaft where it pokes out of the casing through a small, neoprene, disc-style gasket. Now it works and seals just fine.

That said, most of the foam gaskets in my car's heater box and blower housing had disintegrated from age. The control lever assy also needed repairs, along with cleaning and lubricating. Although the system might have worked after the heater valve and control cable were fixed (the heater core was fine), I'm not sure that it would have worked particularly well.

In the end, it all depends on what final result will satisfy you. It may very well be worth pulling the heater valve first and either servicing it or putting in a new one. If you go this route, though, be prepared for a hour or two of awkward work. IIRC, you will need a 1/4"-drive socket set and a stubby Phillips screwdriver (and maybe an offset Phillips screwdriver too). One or two of the Phillips screws may be reluctant to loosen, so its worth spraying all the fasteners with penetrating oil a week or so before you get started.