• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

Header leak problem with macs? Anyone had the same problem?

  • Thread starter Thread starter 1990StangGT
  • Start date Start date Apr 14, 2006

1990StangGT

Founding Member
Jul 1, 2002
361
0
16
Whiteman AFB
Apr 14, 2006
#1
  • Apr 14, 2006
  • #1
Ok I finally installed a set of chrome unequal 1 5/8" mac shortys with a off road prochamber and mac cat back. All the fitment is perfect but as I went to crank it up it sounds like both headers are leaking terribly, I then proceeded to uninstall and then reinstall the headers agian, I know I got the gaskets on right so wtf? Maybe could the headers be messed up? I know I got the headers on and tight but still after 2 tries of installing them still can not get it right? Has anyone had this problem with these headers? If so what exazctly was your scenario, I do not want to take it to the shop this is a darn simple install they just do not want to seem to seal? could it be the copper gaskets? Should I just get some fel pros?
 

JBeezy53

Member
Dec 28, 2003
559
1
19
Sacramento, Ca
Apr 14, 2006
#2
  • Apr 14, 2006
  • #2
I have had problems with them leaking at the collectors.
 

1990StangGT

Founding Member
Jul 1, 2002
361
0
16
Whiteman AFB
Apr 14, 2006
#3
  • Apr 14, 2006
  • #3
well that sounds like where it is coming from on the left side, but on the right you can feel it coming out where the gasket is located. I have tightned and and tightned and it does no good.
 

Strype

Cuthbert catcher
Founding Member
May 11, 1999
61
34
104
Huntsvegas, AL
Apr 14, 2006
#4
  • Apr 14, 2006
  • #4
I have had problems with them leaking where they meet the motor
 

1990StangGT

Founding Member
Jul 1, 2002
361
0
16
Whiteman AFB
Apr 14, 2006
#5
  • Apr 14, 2006
  • #5
What did you do to fix them? Gasket change? I am sure these coppers are junk.
 

legalize420

Active Member
May 21, 2005
1,541
1
37
South Florida
Apr 14, 2006
#6
  • Apr 14, 2006
  • #6
get new gaskets. i used the felpro 1415. i had a bolt back out after i installed mine and was told the copper gaskets are not reuseable. in other words, you can only tighten them down once. my headers have been on and off several times with no problems. you could always put a straight edge across the flanges to be sure its flat.
 
D

dustin440

New Member
Feb 8, 2006
5
0
1
Apr 14, 2006
#7
  • Apr 14, 2006
  • #7
I had the same problem with mine when I bought the car the passenger side was leaking so I got some gaskets from autozone (cheap paper kind) and it still leaked. I tried tightening, running it, retightening it and it still leaked. I finally went to pep boys and got some better gaskets, I think they are made by Mr Gasket and they haven't leaked since.
 

1990StangGT

Founding Member
Jul 1, 2002
361
0
16
Whiteman AFB
Apr 14, 2006
#8
  • Apr 14, 2006
  • #8
Yea I am going to go with the fel pros, I figured the coppers where not reusable. Thanks I will try it.
 

MustangGT92

New Member
Apr 13, 2006
89
0
0
Oklahoma City
Apr 14, 2006
#9
  • Apr 14, 2006
  • #9
i also had that problem...on my passenger side, the back of the motor the bolts would come loose....but you might want to take a level and make sure that the headers are level...
 

1990StangGT

Founding Member
Jul 1, 2002
361
0
16
Whiteman AFB
Apr 14, 2006
#10
  • Apr 14, 2006
  • #10
Well I bought a set of the fel pro oem style and they also came with flange gaskets, do i even need the flange gaskets?
 
1

1insaneGT

New Member
Feb 16, 2003
6
0
0
Atlanta,GA
Apr 16, 2006
#11
  • Apr 16, 2006
  • #11
A couple of guys I know who drag race their stangs quite often had problems with headrer leaks or blwoing the gaskets out. I know they used black high heat gasket maker/sealant. They say it works, I have never tried it and I have MAC equals on mine( leak free w/ mr. gasket gaskets). But before I did that I would definetely make sure that the headers are not warped at the flanges. Good Luck


Drew
 
You must log in or register to reply here.

Similar threads

Drivetrain 83’ Glx convertible C5 Trans help!
  • JacksonJared2113
  • Dec 25, 2025
  • Fox 5.0 Mustang Tech
Replies
2
Views
334
Fox 5.0 Mustang Tech Dec 26, 2025
JacksonJared2113
S
Fuel ‘88 GT Runs Rich Cold — Fixes Itself When I Unplug Sensors (ECT, MAF, O2, etc.)
  • Sufarry
  • Nov 6, 2025
  • Fox 5.0 Mustang Tech
Replies
12
Views
730
Fox 5.0 Mustang Tech Nov 9, 2025
Mustang5L5
R
94’ SN95 - Intermittent lope & bogging at moderate rpm
  • Red5.0ho
  • Nov 2, 2025
  • 1994 - 1995 Specific Tech
Replies
5
Views
388
1994 - 1995 Specific Tech Nov 3, 2025
General karthief
7
1970 Mach 1 Fuel Gauge Issues
  • 70 Mach
  • Jun 13, 2024
  • Classic Mustang Specific Tech
Replies
7
Views
2K
Classic Mustang Specific Tech Sep 1, 2024
Mach1 Driver
M
E
Finished my Fox Hydroboost Install - Tips
  • Engineer Duane
  • Apr 9, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
4
Views
1K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- May 5, 2025
Engineer Duane
E
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang 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?