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

new t-stat still have old probs. wtf?

  • Thread starter Thread starter 88GT4u2nv
  • Start date Start date Dec 1, 2005

88GT4u2nv

New Member
Nov 18, 2004
60
0
0
Wa
Dec 1, 2005
#1
  • Dec 1, 2005
  • #1
spent like 3 hours putting in new 190 t-stat to try to solve heater probs. well after stripping the hole for the lower bolt, and getting that worked out i got it all togeather. flushed my htr core by putting a hose up to both in/out ends of the core and bled the system of air. i went to take it for a drive. ALAS the heater was working. this morning i warmed it up for 10 minutes just to get in to cold air blowing from the vents. my temp gauge is all over the map, heater blows warm for about a min and a half, then will blow cold for a min and a half, all the while my temp gauge goes up and down.

on my work break i open the rad to find it way low on coolent. filled it and the heater worked a little better for a couple minutes then i had the same prob. i got home...same deal, rad was a little low. seems like i might still have a little air in the system.

ps. i used rad flush as well, and im still getting a little foam from the flush ****.

whats going on with this thing...i just want heat!!!
 
8

87'GTstang

New Member
Feb 16, 2004
1,025
0
0
Dec 1, 2005
#2
  • Dec 1, 2005
  • #2
The best way to bleed the system is take the cap off, start the engine, let it run for awhile until fully warmed up. Once you think the t-stat is open, rev the engine a few times to see if the coolant goes down a lot and take note of air bubbles (you might also have it spew out a bit). Main thing is to make sure you get all the air out.

If you keep losing coolant after a while, check the usual, look for any leak whatsoever, check your oil for the classic mocha milkshake, if you still are losing it - may just be a blown headgasket coming up.

edit: Oh yeah, without a constant supply of coolant flowing through the heater core, there will be no heat transfer possible -> so no heat out of your air vents will be possible.
 

vristang

15 Year Member
Mar 31, 2005
4,933
101
124
Seattle
Dec 1, 2005
#3
  • Dec 1, 2005
  • #3
I would start with another system flush. It sounds like you still have flush fluids in the system which are contributing to air pocket formation. Air pockets will prevent any flow of coolant (which can cause lowheater temps, and high block temps). Not until pressure is high enough to overcome the blocking force of the air pocket, will the coolant begin to flow. Two ways that may work, Increase the press of the rad cap. This may have negative affects if the system is old and likely to fail with the new pressure. Or rev the motor a little. A quick blip or 2 of the throttle can produce enough pressure to break up the air pockets.
This time give a good rinse of pure water. Then when satisfied the system is clean, add in the coolant.
Using a jack to raise the rad cap end of the car can help purge air from the system as well.
good luck
jason


:Word:
 

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
9,516
6
99
Arkansas
Dec 2, 2005
#4
  • Dec 2, 2005
  • #4
Experiencing a very similar problem...subscribing.
 
S

ss93cobra

Founding Member
Apr 10, 2002
1,422
1
0
Wilmington NC
Dec 2, 2005
#5
  • Dec 2, 2005
  • #5
I'd have to agree with 2nd post. Sounds like you didn't "burp" the cooling system properly and have since gotten a good amount of air trapped in the system. Follow the directions in the above mentioned post to relieve the system of any trapped air pockets.
 
You must log in or register to reply here.

Similar threads

B
A/C Issues
  • Boats90GT
  • Jun 10, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
2
Views
107
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jun 11, 2026
Mcmahst
M
Resolved 1988 Foxbody - Overheating Summer
  • MDrisc
  • Oct 26, 2025
  • Fox 5.0 Mustang Tech
Replies
16
Views
670
Fox 5.0 Mustang Tech Friday at 12:37 PM
fasterthangas
F
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
503
1996 - 2004 SN95 Mustang -General/Talk- Sep 5, 2025
mnky99
M
G
2005 Mustang GT AC cycling on and off every minute
  • GeorgeSwadling
  • Jul 12, 2025
  • 2005 - 2009 Specific Tech
Replies
0
Views
219
2005 - 2009 Specific Tech Jul 12, 2025
GeorgeSwadling
G
J
'96 Cobra: A/C gets weak and engine misfires under load when warm
  • jruhnke
  • Oct 22, 2025
  • SVT Tech Forum
Replies
2
Views
310
SVT Tech Forum Nov 20, 2025
nickyb
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?