• Mustang Forums
  • 1965 - 1973 Classic Mustangs -General/Talk-
  • Classic Mustang Specific Tech

Heater Core mess again! just two years later...

  • Thread starter Thread starter fitzm65
  • Start date Start date Dec 4, 2003

fitzm65

New Member
Jan 5, 2003
197
0
0
Central Florida (UCF)
Dec 4, 2003
#1
  • Dec 4, 2003
  • #1
I’m pretty annoyed right now… I replaced my leaky heater core about two years ago. To my surprise I pulled out the factory original (or replacement). It had the FoMoCo stamp on it and was just leaking a drip here and there. The other day my new replacement one started leaking all over the place! Lucky I have rubber floor mats and I was almost home or my (already crappy) carpet would have been even more ruined! So now I have to pull apart all of the new crap I rebuilt under the dash ( I know it is not as hard as new car but still!) and replace the stupid core yet again… just two years later. What is a good brand to buy this time around? The one from mustangs unlimited just didn’t cut it and I’m not going through another winter without heat! (and yes, it was installed perfectly just for those who doubt! =-) )
 

68GEETEE

5 Year Member
Nov 21, 2003
481
5
38
Texas, USA
Dec 4, 2003
#2
  • Dec 4, 2003
  • #2
i believe some type of treatment is required before the core is installed. My father in laws Oldsmobile had gone thru 2 heater cores, and it turns out that the shop didnt follow proper procedure which led to the new core going bad. I think he said osmosis or something to that effect. Check the internet and I bet you will see what I am talking about. Also, You should be using distilled water and anti freeze mix, tap water will corrode your system really quick.
 
1

1969mach1351

Member
Apr 18, 2003
285
0
16
Sacramento, CA
Dec 4, 2003
#3
  • Dec 4, 2003
  • #3
I think mine is a Mustangs Unlimited, its been in for about four years. Maybe you just got a bad one? Something that came to mind is if your radiator cap is working and/or if it is too high of pressure to make the core blow. If it was too high pressure I think something would have popped before 2 years though.

I've heard of people using distilled water but my dad never used it and I never have and we have not had any problems.
 
3

351pacecar

Founding Member
Jul 2, 2001
644
0
0
Hudson, Wisconsin
Dec 4, 2003
#4
  • Dec 4, 2003
  • #4
Maybe it had a thin spot on a seam or something.

And what the hell do you need a heater in florida for anyways? I could (and have) gone swimming in the ocean even on cool nights when I visit down there.
 

jcp123

New Member
Nov 1, 2003
408
0
0
Tyler, TX
Dec 4, 2003
#5
  • Dec 4, 2003
  • #5
i had the same problem...mine gave out one fine day about a year after i had put it in...annyoing aint it?
 
D

D.Hearne

New Member
Sep 29, 2000
11,730
6
0
south louisiana
Dec 5, 2003
#6
  • Dec 5, 2003
  • #6
He might try installing a restrictor in the heater hose to keep the pressure and flow down at high rpms.
 
E

ETEL64

Member
Jun 20, 2009
51
0
6
NJ REFUGEE, HOUSTON, TEXAS
Feb 3, 2011
#7
  • Feb 3, 2011
  • #7
Maybe have it pressure checked

I feel your pain man ! I did this once long ago and I think can still see the scars and recall a very sore back.

I imagine a creative Rad shop could pressure test one for you and maybe inspect and repair a thin joint.

Just a suggestion.



351pacecar said:
Maybe it had a thin spot on a seam or something.

And what the hell do you need a heater in florida for anyways? I could (and have) gone swimming in the ocean even on cool nights when I visit down there.
Click to expand...
 

NasaGT

Founding Member
Sep 19, 2002
1,993
2
49
Virginia
Feb 4, 2011
#8
  • Feb 4, 2011
  • #8
You brought back a thread from 2003 to make a suggestion to the original poster? Really???
 
You must log in or register to reply here.

Similar threads

M
2001 evap/heater core questions
  • mnky99
  • Sep 3, 2025
  • SN95 V6 Mustang Tech
Replies
3
Views
305
SN95 V6 Mustang Tech Sep 3, 2025
mnky99
M
M
Progress Thread mnky99 2001 V6 evap core, ac compressor, heater core replacement
  • mnky99
  • Sep 5, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
1
Views
489
1996 - 2004 SN95 Mustang -General/Talk- Sep 5, 2025
mnky99
M
B
Saying Hi
  • BriansNSane
  • Dec 20, 2025
  • The Welcome Wagon
Replies
5
Views
287
The Welcome Wagon Dec 21, 2025
BriansNSane
B
F
Electrical Foxbody wiring harness 2.3 to v8 swap
  • Foxbodyjake
  • Mar 23, 2026
  • Fox 5.0 Mustang Tech
  • 2
Replies
24
Views
680
Fox 5.0 Mustang Tech Apr 13, 2026
Foxbodyjake
F
M
2001 v6 heater hose quick connect question
  • mnky99
  • Sep 24, 2025
  • SN95 V6 Mustang Tech
Replies
8
Views
556
SN95 V6 Mustang Tech Sep 26, 2025
mnky99
M
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1965 - 1973 Classic Mustangs -General/Talk-
  • Classic Mustang Specific Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?