Yep, I think my heater core is on its way to being FUBAR. This morning, I went to get in the truck and I notice a puddle emanating from the passenger side wheel well. Sure enough it was purple antifreeze dripping from the splash guard. I checked the heater hoses and they seemed tight. I tightened them again.

When I move the hose upward on the heater core connector closest to the driver's side, I hear a sucking sound from inside the hose. I am thinking the brass connector has rotted away where it connects to the core. I did not see any fluid dripping from the hose. It seems like it is coming from further in the firewall.

I guess I will bypass it for now being that it is spring. Can anyone post some pictures or how to's of taking the dash apart to get to this thing?

 

heater cores in these trucks are pretty easy. i did mine in about half an hour this winter.
take your glivebox door off and theres a black plastic cover with a bunch of screws in it. remove the screws and take the cover off and your core is right there. then you got to get it turned the right way to get it out.

 

What year is the truck?
A/C?

My 85 has no A/C and the heater box in the firewall area says HI OUTPUT on it in capital letters.
I replaced mine this winter also, took like 30 minutes because I had a spare heater core from the parts truck on hand.
I also modified my heater box last winter when doign the head gaskets, which made removal and installation a whole lot easier.

I think I pulled my glovebox insert out, there's a bunch of screws holding it to the dashboard, and there might have been a few screws holding the heater box? Don't remember really.

Then on the engine side of the firewall, there is like 3 or 4 bolts. The one on the top fo the box, on the fender side, is a real PITA! I ended up using a long 1/4 or 5/16 bolt and putting a stud on the firewall. I used the dremel and enlarged the hole on the heater box and now I just washer and nut the heater core box using that stud. MUCH easier!

The other bolts on the exterior side are a piece of cake and pretty straight-forward...

Then pull the heater hoses, then pull the entire heater assembly off the firewall. Put it on the ground, take the screws out and pull it apart. Pull the heater core out, put the replacement in, and put it all back together...

This could all be worthless too, because I'm pretty sure you have A/C and you heater box is different...

 

I do have A/C. I also have to fix the box that houses the condenser but that is another project in itself.

I'll run to the hardware store on my lunch break and buy a 90 elbow to bypass it for now so it is not leaking. I guess I'll have something to do this weekend.

 

my 88 has AC, but the heater is not as the PITA on these trucks as it is on anything else

 

Factory A/C trucks are rather easy to change the heater core. By the time you have it bypassed, you're 1/2 way there......
As mentioned, access is gained thru the glovebox.

It's the non-A/C trucks that are a bit more of a pain, and they really aren't that bad.

 

Aluminum core or copper/brass core? Any major difference other than 2x the price of the copper one? I am leaning toward aluminum.

 

If it were me, I'd go for the copper/brass unit, given a choice.
The cheaper replacement units don't seem to hold up as well.

 

Well, I think it might have just been the heater hose. I reseated it and the clamp and I did not notice the sucking sound when I moved the hose. I will check it again tomorrow just to be sure.

 

If its leaking outside of the firewall, more likely to be the hose.

Leaks on the inside, or a steamy/fog on the passenger side of the windshield, likely to be the heater core.

Depending on the year, the heater cores are shaped a little differently too. My '88 has the copper/brass one and it has rounded tanks on the ends. My gasser parts truck is either an '89 or a '90, and it has the aluminum heater core that has square tanks. The square tanks are slightly bigger in the corners and don't fit into the rounded tank heater box even though they are almost the same, its enough of a difference.

I found that out the hard way this fall when my core went out with about a day's notice. Had to piece it back together and order the correct one. Then a day later pull off to a rest stop on the highway and do a real quick bypass trying not to get covered in hot coolant. (cold morning so I really wanted the heat, but the pressure opened the leak to where it was pooling out and fogged everything up so I couldn't see a damn thing). The local stores didn't seem to carry the copper/brass one that fits, but rock-auto had it.

 

the new heater cores arent an exact fit, you will have to push it in pretty hard.

 

you can use a 1/2 in peice of copper pipe to bypass your heater core ... i just bought one from O riley parts store it was 22.99 life time warrenty it took about 15 mins to change

 

in preperation for bypassing the core, I went to Home Depot and wound up buying a 3/4" OD 90 degree brass PEX fitting to join the heater hoses. The hoses are 5/8" ID, but I matched the fitting up and it seemed to be a perfect fit. There must be some differences between the two as far as size goes.

The 90 degree fitting is meant to reduce kinking and stress on the heater hoses, versus a 180 degree fitting.

I'll let y'all know what I find in the morning. I think the hose clamp was just misaligned, etc.

 

The 90 degree is a good idea, though I don't think its needed with the length of hoses. But why did you go to the trouble matching up a pex part? In thinking I would need to bypass mine (which I did need to do) I went to Lowes and found a nylon connector made for 5/8" hose. I would think Home Depot, and most hardware stores would have one, and any auto parts store would have them too.

Oreo is right that it does take some force to put them in, but it shouldn't be because of the fit. The original one is put in place with some spray foam insulation around the hoses. The foam acts like a glue and makes it a pain is the *** to remove the core, and requires some effort to push the new one fully back into place. However, as I stated, the copper/brass ones have rounded ends, and the hole in my heater box is rounded to match. The aluminum core has rectangular ends with the box to match. Remember the saying a square peg doesn't fit in a round hole? I don't know what years, and what heater options this reflects. I just know that the aluminum one from the parts truck would not fit in my truck which had a copper core, both trucks have AC.

The comments on either Advance Auto and/or Autozones websites agree with what I had to do. The ones they stock don't fit the way my truck is configured. The copper one they sell doesn't have the right tubes. The aluminum one with the correct tubes doesn't fit my truck.

Your mileage may vary, and since its warm, just bypass the core and take your present one out. Getting to it is easy and only takes a few minutes to pull it out. Then you can see exactly what is in there, and get the right replacement the first time.

 

Tecgod13,

I got the PEX because the sales rep at Home Depot advised me that the PVC solution would not handle 200+ degree temps. The PEX was the only metallic 90 degree elbow I could find that fit the 5/8" hose. I would have preferred a barbed elbow but one was not available. The PEX is ribbed (for her pleasure, I guess) so it should make a good seal.

I think I will take the heater core out this weekend just to inspect it. It seems easy to get to, so no reason why not to.