Heater core inlet/oulet pipes question.

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Nov 1, 2004
Staunton, VA
Vehicle is a 1994 fzj80.

I just replaced the rubber coolant hoses to the inlet and outlet of the heater core and now I have a substantial amount of coolant leaking onto the passenger floor. When removing the hoses I cut them with a razor, but I still had a hell of a time removing them. The passenger side hose, specifically, was vulcanized to the brass nipple on the firewall which resulted in lots of pulling and twisting trying to remove it. My question is how are the brass nipples attached to the heater core? My FSM is worthless (or i'm looking in the wrong spot) for this information. I heard mention of an O-ring somewhere - can someone confirm? Is it possible I somehow unseated the nipple from the core and I can reattach without removing the entire damn interior? Or am I screwed?

Good news please...
They connect using a clamp with an o ring seal. You could have wiggled it loose from the heater core. It's not a fun job getting to the heater core so I would make sure itis not leaking back through the firewall from the hoses in the engine bay being loose.
Ots definitely coming from the heater core. Found out with some fancy mirror work. I'm going to self medicate by ripping off my fender flares.
this is from a 96, not sure if its the same as yours
That looks the same. Does anyone have any pictures of how the pipe actually fits in the heater core?
I got it torn down to where I can see the problem. Holy s**t what a PITA. The passenger side brass tube is corroded and cracked. Looks like it was on the verge and the stress of wrestling off that old coolant hose did it in.

@LockedCollector what year is that heater core out of? The one in my truck does not look like that. It appears that both of the brass pipes have a solo connection to the heater core.
Also, does anyone have any "while you are in there" recommendations? I'm going to replace some dash light bulbs. Anything else?
Clean out your AC thingy, add all the extra wiring you may need in the future.
BlueCruiser You mind posting a pic of your heater core?

I just got all my heater hoses today and I'm about to attempt the same repair, sans the heater core hopefully.
Clean out your AC thingy, add all the extra wiring you may need in the future.

I am going to clean out the blower for sure. Once everything was removed I could see a massive mouse nest in it... What AC thingy are you talking about?

Did you guys have to remove all the AC stuff in order to get the heater assembly out? My fsm says "remove two nuts and one screw. remove heater assembly". The entire procedure in the FSM is one of the more understated "how-tos" I have ever tried to follow.

I'll try to get some pictures tonight. There isn't too much to see. Going after the heater core is very overwhelming once you get into. I keep looking at everything I have moved and removed and thinking "how in the hell am I going to get all this back?".
Yeah that's pretty much what I meant. Sounds like you have a better grasp on things than I did. I did sand and paint all the metal dash braces that were removed.
Got the heater core out.I had read a thread where someone was able to remove the core without disconnecting the AC, but my AC was empty anyways so disconnecting it to move the rest of the HVAC stuff was easy. This made getting the entire heater assembly out much easier. I am also able to clean up the other HVAC assemblies which appear to have 20 yrs of dirt and mouse nests in them.

A couple shots of the heater core. Mine is different than the one posted above. The brass tubes are soldered to the core. You can see where the old tube failed. Looks like it was corroded and weak and tugging on it to get the rubber hose free finished it off.


My AC thing. Could use a good cleaning. How do I determine if it has been leaking or not?

Aaannd the results of my labor.
I there a way to pressurize it using some some air?
thanks for posting those pics. Its good to know the inlet/outlet pipes are soldered that seems like a much better joint than a mechanical type seal. With the corrosion around the leak it looks like it may have been leaking for a while..? Maybe it was as slight leak and really let go once you replaced that hose at the fire wall. I bought new hoses last week but after reading thru your struggles I may opt for the "if it ain't broke don't Fix it"

I assume an A/C shop can pressure test your Evaporator Core and let you know if it's holding. When I bought my truck I had the A/C system charged. After a week or so I thought I was developing the worst allergy attack I'd ever had. Turns out my A/C was leaking and I was inhaling refrigerant.... If you end up having to replace the evaporator core 88501-60101 it was recommended to me that I replace the Expansion block 88515-20100 Receiver Drier 88471-50020 and Hi Flow Valve Cores. (I don't have a part number for those) Replacing those parts fixed my A/C and its works great now.

Hope this helps, and I hope you took a lot of pictures while taking that dash apart. My jaw dropped on that pic.

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