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Signs of a Bad Heater Core??

10K views 16 replies 12 participants last post by  99MustangGTman 
#1 ·
What are the signs? When I cut the heat on in the mornings, a light white smoke comes out the vents. Also, a light smell of antifreeze, plus the defost just fogs up and takes 30 minutes to get rid of the fog. Another thing when the heat is off, after driving the drain tube leaks out liquid like the A/C has been on.
 
#2 ·
all of the above!!

that sure sounds like it to me.

take care,
adam
 
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#3 ·
NOOOOOOOOOOOOO!!:mad: How complicated is it to replace? I have an 86 gt.
 
#4 ·
Check your heater hoses first, i started to replace a HC in an 81 Stang but the heater hose was the prob, and it was doin the same things your car is.

The difficulty of replacemant depends on if you have factory AC or not. Ive done three HC replacements in the 79-86 dash. If you have AC and havent done it before, its gonna take a while, first time took me about four hours, although now i could do it in about 2.5 i think.

Does your car have AC? I could try to type it out from memory, but would rather not if you dont have AC.

If you dont have AC, just take the glovebox out, and youll see a cover behind where the glovebox was. Take the screws out and youll see the HC, take the heaterhoses off, push the HC out of the heaterbox a little from the firewall side, then pull it out of the glovebox opening, 15 mins and your done.

Zach
 
#5 ·
It is not all that hard, just time consuming. If you don't have AC then just drop your glovebox and the access panel is right there, straight forward. Having done this a couple of times there is no real "short cut" About a 3 hour job, the dash comes apart one piece at a time and is pretty straght forward. Big thing is to baggie and label screws as well as vac lines. PITA when you are looking for where things go. Some people recommend the FORD unit, me I figured they screwed it the first time what is to stop them a second, so in went a unit from Pep Boys. 20 bucks or there abouts. Put JB weld around the in and out tubes this way you will not have to be REAL careful hooking the heater hoses back up. You will see that there is not a whole bunch there. It will take you about 3-4 hours to do. The only "special" tool that was needed was those star screwdrivers. Ford will charge you about 400 to do the job.

Try doing a search on the boards, there was a guy awhile back that put out some awesome detailed instructions on this.
 
#6 · (Edited)
J.bo It is easy. But it takes time to do it. I have done this on my 82GT 3 times already. Drop the sterring colum remove the 5 9/32 bolts that hold the dash to the firewall and theres a bolt on each kick panel to remove and pull dash out just enough to slice open the box that holds the core in with a dremal. Have a buddy with you to help put new one in and guide it through the firewall. Here is a link to some pics of mine. I would get a Ford heater core the parts store ones that cost 20 buks are junk and prolly wont last a year. Let me know how it goes. http://mywebpages.comcast.net/mike82gt/heatercore/
 
#7 ·
Check your heater hoses first, i started to replace a HC in an 81 Stang but the heater hose was the prob, and it was
What was the problem with the hoses? I replaced the small hose about 1 month ago.
What can I use to cap off the heater lines until I change the core.
 
#8 ·
The problem with the heater hos was that the bigger one was was leaking right at the firewall, allowing a little bit of steam to shoot into the heaterbox.

I didnt hack into my heaterbox like mikejb did, i took it out. He forgot one bolt though, not only are there two holding the dash shell on at the kick panels, but one more behind the radio on the drivers side of the dash.
 
#9 ·
Thanks guys for all the help. I put on some bypass caps yesterday until I find time to change out the heater core.

Zephry, I checked my hoses and they are o.k.

I almost forgot, when I drained a little of the coolent yesterday, when pouring it back, in the drain pan were particals of brass most likely from the core gone bad.
 
#12 ·
"signs"

And the sign said
"Long-haired freaky people
Need not apply"
So I tucked my hair up under my hat
And I went in to ask him why
He said, "You look like a fine upstandin' young man
I think you'll do"
So I took off my hat and said, "Imagine that
Huh, me workin' for you"
Whoa
Sign, sign
Everywhere a sign
Blockin' out the scenery
Breakin' my mind
Do this, don't do that
Can't you read the sign?
And the sign said
"Anybody caught trespassin'
Will be shot on sight"
So I jumped on the fence and I yelled at the house
"Hey! What gives you the right
To put up a fence to keep me out
But to keep Mother Nature in?
If God was here, he'd tell you to your face
'Man, you're some kind of sinner'"
Sign, sign
Everywhere a sign
Blockin' out the scenery
Breakin' my mind
Do this, don't do that
Can't you read the sign?
Now, hey you, mister, can't you read?
You got to have a shirt and tie to get a seat
You can't even watch, no, you can't eat
You ain't supposed to be here
The sign said, "You've got to have a membership card
To get inside"
Uh
And the sign said
"Everybody welcome
Come in, kneel down and pray"
But when they passed around the plate at the end of it all
I didn't have a penny to pay
So I got me a pen and a paper
And I made up my own little sign
I said, "Thank you, Lord, for thinkin' 'bout me
I'm alive and doin' fine"
Woo!
Sign, sign
Everywhere a sign
Blockin' out the scenery
Breakin' my mind
Do this, don't do that
Can't you read the sign?
Sign, sign
Everywhere a sign
 
#14 ·
I blame you for my coworkers having to hear me sing this at work today.

Of course a poster named 'Rona kicked this thread practically from the last millennium. :rolleyes:
 
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#17 ·
After 19 years, I sure do hope he finally fixed the heater core. I just bought my 86 GT and it must have been leaking because the hoses going into the core are connected together and I have no heat. Also, one of the previous owners decided to remove the factory A/C, because that 12-15lbs or so is going to really make it a race car now. When I was a kid in the early 90s I helped my dad pull the A/C off his Fox since at the time, it was more the trend and thought that the factory A/C unit was heavy. Once we pulled it all off we couldn't believe how little everything weighed, including the factory lines. I'm not saying it was something I could lift with my pinky, but it's something we wished we left in there. Not worth it at all to remove for what little gains you receive in weight advantage and removal of the pulley system. Thankfully whomever had my car before me must have realized the heater core went bad and was too lazy to replace it and tied the lines together, also removed the factory A/C, and removed the SMOG pump. The last one i'm ok with.

It's funny though, I remember in the mid 90s it was almost a fad to pull the A/C system as everyone thought it was an easy way to gain some power. Oh well, live and learn.
 
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