heater core removal question, help, etc.

[zoomsplatt]

hello all
in need of some help concerning my heater, I've downloaded the factory service manual but there doesn't seem to be a section in it that deals with the heater core or how to remove it or any of the components around it, I'm pretty sure I can figure it out but it's always nice to have a parts breakdown to check, I already know what my problem is- I think- I've got something sitting on my heater core stopping the flow of air from my fan, all my passageways have been cleaned in my fan is putting out plenty of air, just once it gets to the heater core it won't go through, no matter what position I put the controls, the heater core is getting plenty warm enough is nothing passing through it so I figure there is either a bunch of mold, leaves, mouse nest, Or some other form of blockage sitting on top or in the fins of the heater core itself, whatever it is I've got to disassemble my under dash and get at the core so if anybody's got a parts breakdown or a copy of the chassis or body manual please let me know.

[danzo]

Are you sure your heater core is getting warm enough? When your car has been running for 10+ minutes what does the dash temp gauge read? If it's accurate and substantially below the halfway mark then you most likely have a stuck thermostat. This is way easier to replace than removing and replacing the heater core, so I would check the t-stat first. Your heater putting out plenty of air suggests your heater core is not clogged.

[Highlander]

We need more information- How do you know that the heater core is getting plenty hot? AC or non-AC car? These cars typically have relatively low flow rates to the foot area. To get to the top of the heater core, pull the glove box (2 screws) then pull the duct from the blower to the heater core (more difficult if its an AC car)-Three screws/bolts. you can now get to the air doors that direct the air into or around the heater core (See my topic about heaters from ~ 12/20/09). When you move the heat slider, the air doors move to redirect the air flow. You may have a cable disconnected so that the heater never opens the foot door or something like that. Hope you can get into the heater core now.

[ARCHINSTL]

The FSM completely ignores the heater box. Go to the AC section and there is some info when you get to the "cooling unit" section - but not much.
A better idea is to go to the AutoZone site, enter your car, and then proceed to the heater section - it takes a bit of digging. There are a number of photos/diagrams/printed info which seemingly are from a FSM - but neither in the one on our site nor in the actual, real, Toy, FSM for 1986 which I have (the real, dead-tree, printed version).
Another resource is to go to the Parts Forum here and then go to the EPC sticky and scroll down a bit to the revised link. You can enter your VIN number and then go to the Electrical section, and you can find exploded drawings - a great help.

Do you have an AC-equipped car? Mine is, although since the system is dead, I removed the cooling unit and substituted the OE intermediate duct kindly supplied by another member. I found the AC unit's fins to be virtually clogged with assorted debris - it was a wonder that any air penetrated to the heater core! I now have MUCH improved air flow and even more heat!
If lucky, the AC unit is blocking the air flow - although you have to remove it to clean it, which means evacuating the system - if it still works.

Highlander has some great info, as mentioned. You might also check to make sure the cable is fully opening the water control valve on the firewall - mine does not open all of the way, so despite cable adjustment efforts, I just open it all of the way by hand in the Winter and close it in the Summer.

Our heater system is kinda primitive by today's standards. Air always blows through the dash vents, despite being set on Defrost only or Foot only. The only way to direct more to, say, Foot, is to close the dash vents (and, some air always comes out the Defrost vents.

There are some recent threads on the heater core, and also this great oldie, recently revived.
https://tercel4wd.com/forums/viewtopic.php? ... lit=heater
Tom M.

[garyfish]

There's info & photos on heater core removal/installation at the online Auto Repair Reference Center, which can be accessed through the "Repair Guides" section of the T4WD forum at viewtopic.php?f=7&t=4633

Once you enter the year, make & model of your vehicle, the easiest way to bring up the info is to do a Search for the word "heater" (click the Search icon above the left sidebar). A list of options will appear in the left sidebar, and you should select "HEATER" in all capital letters. Then just use the arrows in the right frame to scroll through the heater section until you arrive at the pertinent info.

Good luck, and keep us updated on how your repair work goes.

[Petros]

It is easy to get to the heater core without removing it. Remove the glove box and than you can remove the duct that joins the blower (on the right side above the passenger foot well) and the heater box in the center. The duct is held in place with only a few screws. If you have air conditioner this is more complicated, the evaporator is in this duct. You will have to remove the refrigerant hoses from the engine compartment side of the firewall to get the duct assembly out of the way (if your system is changed you will loose the refrigerant and have to have it recharged).

Once you have this duct off you can see the top side of the heater core with a flash light, and you can see the lower side through the out let vents. The fan can also get debris or rodent nests that block airflow, it is not difficult to remove at this point either. Also operate the heater controls and verify all the flaps and doors are working properly, these can block air flow too if they are stuck.

I have removed several heaters, you have to dismantle the whole dash assembly, starting with the center console. I think you can remove it without removing the upper dash panel, but I always have removed it. Access is much easier without the dash in the way. It is not difficult to remove everything, but you should use Armorall or similar to lubricate the plastic parts that have to pop off. When they are old they get brittle and it is easy to damage them when trying to remove the dash. Us a putty kniff wound the vent grills to work the free (they will stick to vinyl when you try and remove them).

Good luck.