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

Thermactor plug

  • Thread starter Thread starter 281pony
  • Start date Start date Nov 15, 2004

281pony

Active Member
Aug 31, 2003
2,681
2
46
Oly, WA
Nov 15, 2004
#1
  • Nov 15, 2004
  • #1
im about to start my new engine for the first time and im going over everything. yesterday i bumped it a couple times to make sure it was going to turn over. just two quick bumps.

on my passenger side head, the thermactor plug on the front of the engine is missing where the bracket bolt goes. will the absense of the plug cause a major airleak?

just wondering, i heard some compression hissing out after the bumps i think and thats the only leak i can really think of it would have. i tried to feel around but it goes just as deep as the screwdriver tip i was using, are they just straight through or will it cause an airleak?

thanks
 

bmorrisj

Member
Sep 26, 2003
449
0
17
Buena Park, CA
Nov 15, 2004
#2
  • Nov 15, 2004
  • #2
yes i would plug it, thats how smog pump air gets in the heads....
 

281pony

Active Member
Aug 31, 2003
2,681
2
46
Oly, WA
Nov 15, 2004
#3
  • Nov 15, 2004
  • #3
the rear is plugged already.

the front is what im wondering about. does it go straight through the head completely?

i can get a plug eventually reguardless, its just right now i dont have transportation until my car is up and running. i dont want a massive airleak now and im trying to get something resolved before first startup.
 

bmorrisj

Member
Sep 26, 2003
449
0
17
Buena Park, CA
Nov 15, 2004
#4
  • Nov 15, 2004
  • #4
well technically there is no front or back to the heads, they are both the same, you can install them any which way you want ... the thermactor holes/plugs are there really to just thread bolts into the heads(front brackets) or for the crossover tube (rear emissions)
 

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
9,516
6
99
Arkansas
Nov 15, 2004
#5
  • Nov 15, 2004
  • #5
You will have a leak at the front because as stated there isn't really a front or a back...the holes match on both sides...

Put some silicone on them when you install them and "twist" them in until they stop...

You will need the plug in the front anyways because the inside of the thermactor plug is the size threads you need to put your alternator bolt/power steering stud in...it will not thread in without the plugs...

They "plug" up the hole where the smog equipment goes (the same thing works for the front of you heads...you can get them at a Ford Dealership - part # F4ZZ-6E086-A or you can buy some from Summitracing - part # TFS-51400265...when you put them in the front of your heads your alternator bolt and power steering stud will screw right in perfectly...when I first seen they were to the heads hole threads were to big doing my h/c/i swap...I thought I put the heads on backwards
 
You must log in or register to reply here.

Similar threads

K
Electrical 2000 GT Intermittent Engine Shutdown In Motion - DTC U1262
  • kenster1092
  • Apr 13, 2026
  • SN95 4.6L Mustang Tech
Replies
4
Views
128
SN95 4.6L Mustang Tech Apr 24, 2026
squeak93
B
Engine Another no start after washing engine bay
  • bruno
  • Apr 26, 2026
  • Fox 5.0 Mustang Tech
  • 2
Replies
24
Views
482
Fox 5.0 Mustang Tech May 7, 2026
AeroCoupe
9
Engine Donor '00 Mountaineer meet '91 Fox
  • 91firecracker
  • May 11, 2026
  • Fox 5.0 Mustang Tech
  • 2 3
Replies
41
Views
505
Fox 5.0 Mustang Tech May 28, 2026
91firecracker
9
L
Engine Why won't the motor start if I have spark and fuel
  • LeviAnderson
  • Nov 20, 2025
  • Fox 5.0 Mustang Tech
Replies
3
Views
365
Fox 5.0 Mustang Tech Nov 20, 2025
AeroCoupe
J
'04 3.8L V6 mineral deposits and oil on #3 cylinder. Does it need a rebuild or something simpler?
  • joeybuddy96
  • Mar 18, 2026
  • SN95 V6 Mustang Tech
Replies
4
Views
188
SN95 V6 Mustang Tech Mar 18, 2026
joeybuddy96
J
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?