My 85 ExtraCab has no ac and had no heat either but, the Taiwanese heater core that coat me $35.00 shipped from eBay is delivering engine heat to the cab now and it kicks ass.
The original core is clogged with rust.
I had never changed a heater core before so it took me about 8 hours to get it done but, I had no extra parts left over and I also removed a 30 year old non functional Sentry alarm system then rewired my stereo system.
Going wheeling this Friday up near Gorman over 4000', a heater is going to be mandatory.

 

8 hours on a heater core swap for the first time is pretty good. It is a big job to do. Glad you mentioned where you got your core. I am thinking of swapping mine out with one that might get hotter.

 

That one has the tubes and is $40 cheaper than the one I found.

THANK YOU!

 

Cool post.

I know heater core is not tip top. I have flushed it checked mixer valve, burped, sealed gap between blower motor and were it sits. I keep a thermometer placed in center vent blows out 100* - 105*. Seems to blow warmest with driving, with good air movement. I may just be spoiled. Planning to pull dash in spring,

Happy New Years!!

 

If I can just get this metal clip to seat and stop leaking I'll be done. I'm bashing my head against the wall trying to get this piece of crap on there. I'm having a beer after this.

 

Tube going into heater core will not stop leaking. Going to try some RTV sealant to help it. Man it's frustrating being almost there

 

I sent you tubes and clips and the Post Office said it would be 2 days shipping. It should of been there today. Put one hand on the core and one on the tube and squeeze together. Do not try and squeeze the flanges together as they will bend. The clips have to be on 100% correct or it will leak. The clips have just enough flex to slide over the flanges.

I cant recall right off but I am sure there is a rubber O-ring on the tubes. Did you install it? I think the tubes I sent have them on still.

 

I got off of work today and chugged a bunch of coffee, crunk up some Bob seger, and swapped out the new heater core for a used one in good condition. Heat is blowing HOT and I didn't even have to burp the system. Probably attributable to how much I've burped it, but whatever. I will be able to feel my hands on the drive to work in the morning.

The spectra heater core I purchased did not have the proper flanges to mate to the core tubes, thus creating a very awesome leak and negating any kind of heat. I'm not even gonna send it back. I just don't care. My heat works now.

Lessons learned:

The cable to the heater control valve was broken at the lever. I fixed it using a screw and a very stout wire connector. Tested it vigorously - jury rig approved.

OEM Thermostat probably helped more than anything. Old one wasn't sending fluid to the core.

If you're reading this and contemplating changing out your heater core, heed Terrys87s advice: make SURE you've got the C clips on the core tubes and the core flange as needed. This is the most critical part of this job.

PRESSURE TEST. PRESSURE TEST. PRESSURE TEST. IMPERATIVE.

Get the core in the blend box or whatever, get it in the cab, hook up the hoses at the firewall, then run the truck. Then drive it around for a little bit. Then check for fluid at the flanges at the core. Or else you will be taking everything back apart.

I recommend using a thin layer of red RTV on the core tubes, but not enough to compromise the C clips seal.

It took me 3 tries to get this right but I did it today, start to finish, in 3 hours.

Thanks YT. most uplifting fix I've accomplished yet using this site.

 

Just curious where in Alabama does it get that cold .

Northeast Corner up around Hollywood??

 

At 5 am, everywhere

 

I put a dash all back together without testing it and it leaked. Good advise on the test drive before finishing the job. That was a total pain in the rear having to go back and do it all again.

 

Some good advice I found was replacing the radiator cap. Whole system has the right amount of pressure again which is great.

But yeah the second time I did it I let it run and run (like an hour, while burping the system) and it didn't leak. So I put the dash back together. Then I drove to the store and had coolant in my floor and the heat stopped. I was so frustrated I couldn't touch it again until yesterday. Thanks for the hardware dude. I'm still looking for those bumper caps!!

 

I found them on ebay for $35.00 shipped and now they are only $24.00 shipped
http://m.ebay.com/itm/1984-1989-4Runner-84-88-4WD-Pickup-Front-Bumper-End-Cap-Set-Lh-Rh-New-/171508149335?nav=SEARCH

 

Thanks fastspider... The ones I am looking for are for a rear chrome bumper. I think the only rear bumper that has plastic caps on them and just so happens that is the bumper I decided to go with my truck.

 

have you checked the vent foam seals a 1984 truck im sure they need some love my 1985 4runner had horrible heat output once i switched out the foam gaskets on the plastic underdash parts it sealed up and had more air flow so more heat output . home depot in the hvac area has foam

 

Just a note here, I have seen the lever on top of the hot water valve come loose inside the valve so that when the cable operated the valve the ball valve inside didn't turn as far as it should. Hope that's clear.