raggmann

So I need to swap out my heater core.
There's very little heat in the cab although the engine is at operation temps.
One heater "pipe" is way hotter than the other so I figure the core is plugged.
For the $53 replacement core, to me there's no point even trying to flush the core out.
I don't have a/c. Doing a search here and in the FSM, all the breakdowns seem to show heater boxes with a/c. My '93 doesn't have the in-line water valve in the heater hose and the heater control is all cables-no vaccuum actuated mode doors.
Is this the "proper" heater box for a '93?
I'm assuming it should be easier to change than a truck with a/c, am I wrong?

ofcmarc

Its still gonna be a PITA even without the a/c. You have to pull he whole heater box assembly out from under the dash to replace the core.

GLHS

Be prepared to buy extra foam to wrap around the new core and/or corners to get a tight seal.

raggmann

Like where the heater box joins the kick panel on the passenfer side, or??

Alec

No, where the core sits in the box. It is a pain, but not horrible with no a/c. You have to take the steel brace out under the dash on the passengers side, and spend a lot of time lying on the passengers floor . . .

I hope you have space inside to do it in the winter, though.

raggmann

The new core actually came wrapped in foam.
It's a Spectra Premium core.
I'll try and get a pic and maybe document the swap as all the info here seems to be with a/c.
http://ecat.spectrapremium.com/apps/...roduct_catalog
http://ecat.spectrapremium.com/apps/...0&splash=false

As far as your comment "I hope you have space inside to do it in the winter, though" yeah,I have my choice of a couple shops to use. Good thing too as it's only warmed upto -16C right now. It is supposed to get as high as +4C Christmas day though.

raggmann

Ok,further to my question about the heater box........
Is there a water valve in a '93 heater box and if so where is it?
It's not under the hood in-line in the heater hose.
I have cardboard between the intercooler and rad and the temp gauge in the dash comes up to where it usually runs at operating temp.There IS warmish air coming out of the defroster vents but not as much coming out the floor vent.The heater box doors are cable operasted not vaccuum.I've adjusted the cables as per the FSM.The fan still has all 3 speeds so I know the blower resistor is working but there doesn't seem to be the air flow I think there should be.
Possibly a weakening fan motor?Junk in the box?
Being I don't have a/c I can't see the heater box being full of the "crud" most are experiencing but.......
Even at -20C I drive this truck for approx 20-30 minutes,pop the hood,and feel the water pipes feeding the heater core.1 hose is HOT to the touch and I can't keep my hand on it for more than a second or two.The other hose is warm/hot but not soo much that I can't hold it.
I've got the replacement core sitting in the truck and was planning on changing it after Christmas but if the general thought it could be something else I'd rather not have to tear the dash apart.
What are your thoughts?

TIA and have a good x-mas all.

ofcmarc

Have you actually opened up the box to see if there is a bunch of crud in there?

100# of leaves and whatnot will restrict the airflow.

Jim5870

AC or not you'll still get crud in the box.
Check the floor kick panel fresh air vents to see if
they might be stuck open.

dzl_damon

If one pipe is hot and the other is cold, that means you are getting heat exchanged.

raggmann

dzl_damon "that means you are getting heat exchanged" do you maybe mean NOT getting exchanged?

ofcmarc and Jim5870, mines got the "trap door" in the r/h corner of the box.
I used a mirror & light to shine/look in the box. I didn't see anything that way.

Guess I'll tear into it Monday.

SmokemS

i just pulled my heater box out in my 93 without the a/c and i had the box out and new core in about an hour and i'm not mech by anymeans.......its really easy actually make sure you pull the big bolt out on the kick panel on the pass side and when you take your glove box out there are 2 bolts on the left side used for a brace make sure you take that out and then you can flex the dash as much as you need.....then after the glove box is out you'll see a little black box with a pigtail connector with a bunch of wires out it is held up with three screws take that out and you shouldn't have to much of a problem wiggling that box out

raggmann

Thanks Smoke.
you didn't run across any sort of a water valve did you?
That "black box" is the ABS control,just a FYI.
I was hoping it wouldn't be an all day event.I JUST finished with the front diff....re-packed the wheel bearings,replace to spindle bearings,new steering nuckle u-joints,etc. and didn't want it parked for another 2 days over the heater core.

Jim5870

Here is a general guide for removing the box with AC.
It should be similar for you, even easier since no AC.

https://www.dieseltruckresource.com/....html?t=248580

ofcmarc

The first heater core I did was a '88 gasser w/o a/c. It took about 4-5 hours. I did it outside in the driveway at 40* and it was raining.......