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

HELP! Overheating

  • Thread starter Thread starter Maryland Stang
  • Start date Start date May 3, 2008

Maryland Stang

Active Member
Aug 21, 2002
1,656
30
39
Greenville, NC
May 3, 2008
#1
  • May 3, 2008
  • #1
Hey All,

Over the winter I did a H/C/I project on my 82,000 mile stock block 92 5.0. The mods are listed in my sig.

When I first started the car it was overheating and continued to push the antifreeze back out of the cooling system.

I did everything.

Jack the left side of the car up when filling.

Replaced the t-stat and tested both t-stats in boiling water to confirm they are opening.

Removed the temp sensor to check for an air pocket.

Replaced the temp sensor.

The radiator is a large Granatelli Aluminum that is very clean inside and flowing very well.

The rad cap is confirmed 16 pounds.

The water pump is a Jegs high flow and is in very good shape.

The heater and bypass hoses are in great shape and hooked up properly.

The head gaskets are on properly and the tabs are sticking out of the front of the engine.

I did a compression test yesterday and the results were from 155 to 165.

Okay, back to the problem. It overheated about 6 times until I took it to the shop that worked my cylinder heads. They saw what it was doing and got an infrared thermometer out and just as they did that the t-stat finally decided to open. He took a reading on the water neck and it was right at 190. The t-stat is rated at 195.

He told me not to fill the rad all of the way up. He said that he had seen cars that don't like to have the rad filled all of the way up and to just watch it for a while.

At that point the overflow tank was filled but the rad was down so I went on down the road and everything was fine. Over the last couple of weeks the car has been fine. I have driven it all over the place with no problems but little by little the cooling system was pulling the antifreeze out of the overflow tank back into the cooling system.

I checked the level in the rad one day last week and the rad was filled and the overflow tank was down to the Full Cold mark. I thought to myself that the system had worked it's problems out and everything was fine.

Yesterday I was going for a short ride (5 miles to town and back) and it started overheating and blowing the antifreeze out again. That's when I saw another mechanic with 35 years of experience and he said it was the head gaskets and told me to check the compression. Like I said above the test came up from 155 to 165.

There is no antifreeze in the oil and no steam coming out of the exhaust.

I thought about removing the t-stat all together and see what it does. I know it will probably take a while to get warm but I have to do something here. I was also considering drilling a 1/4" hole in one of the t-stats and see what that does.

Any thoughts or suggestions?
 
M

MYSC351

New Member
Apr 9, 2008
48
0
0
May 3, 2008
#2
  • May 3, 2008
  • #2
When you say overheating, are you assumming it's overheating because it's spitting antifreeze or is the gauge going way up? Also is the antifreeze "spitting" out of the radiator and not going into the overflow? Just trying to clarify.
 

93notchback

Member
Apr 5, 2005
39
0
6
Soperton, GA
May 3, 2008
#3
  • May 3, 2008
  • #3
its sounds like you have a head gasket on backwards. it will still have good compression, it just blocks the coolant passages because one end of the gasket isnt open.
 

LiquidGT

Member
Oct 8, 2007
368
0
16
Near STL hell
May 3, 2008
#4
  • May 3, 2008
  • #4
Also, are you putting the themostat in backwards, is your water pump the right rotation or is your water pump spinning the wrong way because of ''custom'' belt routing? I know they might sound like stupid questions, but its hard to tell when you're not there.

I had problems with a warped radiator cap flange, I kept replacing the caps and they would eventually warp too.
 

Maryland Stang

Active Member
Aug 21, 2002
1,656
30
39
Greenville, NC
May 4, 2008
#5
  • May 4, 2008
  • #5
MYSC351 said:
When you say overheating, are you assumming it's overheating because it's spitting antifreeze or is the gauge going way up? Also is the antifreeze "spitting" out of the radiator and not going into the overflow? Just trying to clarify.
Click to expand...

The antifreeze is filling the overflow tank. Once it fills the tank it is coming out all over the place. It puked out almost a gallon Friday. The gauge is almost pegging when it does this. When it's not over heating the gauge hangs around the middle to 5/8 of the way up the gauge.

93notchback said:
its sounds like you have a head gasket on backwards. it will still have good compression, it just blocks the coolant passages because one end of the gasket isnt open.
Click to expand...

The gaskets are confirmed to be on correctly. They're Felpro gaskets. The left hand gasket is "right side up" and the right gasket is upside down. The tab on the front of the head gasket is sticking out of the front of the block on both heads. I've had 2 full time mechanics look at the gaskets and they are on correctly. One of the mechanics bleeds Ford blue and used to build cylinder heads for Junior Johnson.

LiquidGT said:
Also, are you putting the themostat in backwards, is your water pump the right rotation or is your water pump spinning the wrong way because of ''custom'' belt routing? I know they might sound like stupid questions, but its hard to tell when you're not there.

I had problems with a warped radiator cap flange, I kept replacing the caps and they would eventually warp too.
Click to expand...

I removed the t-stat and replaced it with another one. The spring is pointed towards the engine. The water pump is rotating in the opposite direction of the crank. This is the same water pump that I had on the car prior to the H/C/I project and it worked fine before. It's also the same rad I had before and I had zero problems with it.
 
You must log in or register to reply here.

Similar threads

Engine 1986 GT Overheating issues
  • 86 5O GT
  • Jan 25, 2026
  • Fox 5.0 Mustang Tech
Replies
18
Views
677
Fox 5.0 Mustang Tech Jan 29, 2026
86 5O GT
M
Electrical 93 5.0 No Injector Pulse
  • machinermac
  • Jul 26, 2026
  • Fox 5.0 Mustang Tech
Replies
15
Views
220
Fox 5.0 Mustang Tech Aug 1, 2026
Willybill32
L
Car has been overheating. Not sure what is causing it. Any help would be appreciated.
  • Luckysgirl
  • Jun 2, 2026
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
2
Views
141
1996 - 2004 SN95 Mustang -General/Talk- Jun 2, 2026
Luckysgirl
L
Exhaust Exhaust resonance
  • keel
  • Jul 24, 2026
  • Fox 5.0 Mustang Tech
Replies
10
Views
198
Fox 5.0 Mustang Tech Yesterday at 2:51 PM
keel
B
2001 SVT Cobra Overheating Issue
  • bradencaron0
  • May 8, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
1
Views
215
1996 - 2004 SN95 Mustang -General/Talk- May 8, 2025
Noobz347
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?