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

5.0 Engine Trouble!!!

  • Thread starter Thread starter TCullen
  • Start date Start date Jan 16, 2007
T

TCullen

New Member
Jul 6, 2006
28
0
0
West Chester, Pa
Jan 16, 2007
#1
  • Jan 16, 2007
  • #1
I recently installed a 5.0 roller motor from an 86' SCCA car in my 67 notchback. The problem is in the cooling system. I have a 2 row radiator and stock fan and shroud from a fox body. The radiator cap and thermostat are brand new and she's got a jeg's overflow tank.

When the car is started, the temp gague will creep up slowly, like over 15 min to overheating. The strange thing is that the heater in the car will be ice cold. Then, if the pressure (steam) is released, the car will run in the middle temperature range and the heater will blow moderately warm heat.

Do I have an air pocket in my engine or should I be thinking about a head gasket replacement? I've checked the plugs and they all look to be ok. And I know the next step is to compression check, and that's going to happen asap.

Any thoughts??? Thanks for your help
 
D

D.Hearne

New Member
Sep 29, 2000
11,730
6
0
south louisiana
Jan 16, 2007
#2
  • Jan 16, 2007
  • #2
Sounds like an air pocket to me.
 

65ShelbyClone

Founding Member
Sep 9, 2000
4,675
38
119
Antelope Valley, SoCal
Jan 17, 2007
#3
  • Jan 17, 2007
  • #3
+1. A Fox 2-row also is only sufficient for stock and mild engines IMO, but get the air out before you go buying anything
 

347Fastback

Member
Nov 30, 2003
340
0
17
Central Coast
Jan 17, 2007
#4
  • Jan 17, 2007
  • #4
Drill a hole in the thermostat at 12 O clock position and it will burb your system...
 
T

TCullen

New Member
Jul 6, 2006
28
0
0
West Chester, Pa
Jan 17, 2007
#5
  • Jan 17, 2007
  • #5
Hopefully you are right. I would like nothing more than to spend this weekend inside. What are my options as far as bleeding or blurbing the engine back to functionality?
 

woodsnake

15 Year Member
Jan 16, 2007
1,352
15
69
Hicksville, NY
Jan 17, 2007
#6
  • Jan 17, 2007
  • #6
Try running the engine for a few minutes with the radiator cap on only 'half way'. Not fully seated, but not all the way off.
 
R

ron67fb

Founding Member
Aug 3, 2001
1,117
0
36
SF Bay area, CA
Jan 17, 2007
#7
  • Jan 17, 2007
  • #7
How well do you trust your gauge and/or temp sensor?

How exactly are you releasing steam?
 

Decurion

Member
Sep 28, 2006
353
0
16
Livonia, MI
Jan 17, 2007
#8
  • Jan 17, 2007
  • #8
The really bling way to fill your cooling system is to start with it empty, then use a air operated vacuum pump to put the system under 20" or so of vacuum, then use the hose thats attached to the pump, open the valve and suck the coolant in. This is how I did it when I was working for Ford and Daimler/Chrysler building prototype trucks. It works great and you never have to burp the system.
 

65ShelbyClone

Founding Member
Sep 9, 2000
4,675
38
119
Antelope Valley, SoCal
Jan 17, 2007
#9
  • Jan 17, 2007
  • #9
And if you want to be really L337 you could degas the coolant water before hand.
 
C

chromedog

New Member
Jan 13, 2006
554
0
0
worlds center for speed
Jan 17, 2007
#10
  • Jan 17, 2007
  • #10
had a 96 sable with no radiator cap, just a surge tank cap, that was the only way we could get all the air out of the system. we even let it run for a couple hours with the cap loose before we decided to pump the system down... worked like a charm!
 
7

70XR7ConvertCat

Member
Jun 1, 2004
0
0
6
Livermore, California
Jan 17, 2007
#11
  • Jan 17, 2007
  • #11
The 1986 - 1993 5.0L engines used a reverse flow water pump. You didn't mention whether you accounted for this. If you pasted your 1967 accessories onto the front of said motor, where does that leave you?
 

65ShelbyClone

Founding Member
Sep 9, 2000
4,675
38
119
Antelope Valley, SoCal
Jan 17, 2007
#12
  • Jan 17, 2007
  • #12
The serpentine belt engines use a reverse rotation pump, not reverse flow. Latemodel Chevies have reverse flow.

Both the timing cover and water pump are different.
 
7

70XR7ConvertCat

Member
Jun 1, 2004
0
0
6
Livermore, California
Jan 18, 2007
#13
  • Jan 18, 2007
  • #13
65ShelbyClone said:
The serpentine belt engines use a reverse rotation pump, not reverse flow. Latemodel Chevies have reverse flow.

Both the timing cover and water pump are different.
Click to expand...

Yes, you're correct. A poor choice of words. The question remains about the mix and match. It's more common for a parts guy to sell a reverse rotation pump to someone with an earlier block, and non-serpentine belt drive. One other idea which comes to mind is the thermostat (provided it's not upside down). It's easy enough to check whether it's defective. Get a thermometer and place it in a pot of water on the stove.
 
T

TCullen

New Member
Jul 6, 2006
28
0
0
West Chester, Pa
Jan 18, 2007
#14
  • Jan 18, 2007
  • #14
the accessories are all original from the 86. i just used a canton pan so that i would have a dipstick, so no trouble with the waterpump.

the only way that it will run without overheating is if i open the pressure release on the radiator cap. otherwise it will build up an unreasonable amount of pressure and overheat. she runs at 1/2 temp but no heat whatsoever
 

montegoman351

Member
Jan 12, 2007
169
1
18
Jan 18, 2007
#15
  • Jan 18, 2007
  • #15
I'd have to agree with drilling the t'stat. I've done it to several thermostats, stock Ford ones usually have the "jiggler" to release the air, but aftermarket ones usually don't. I drill a 1/16" hole in the t'stat, clock it towards the top, and it works everytime.
 
F

fast4cheap

New Member
Jan 22, 2007
82
0
0
north carolina
Jan 23, 2007
#16
  • Jan 23, 2007
  • #16
accessories may be all 86 but make sure you have the belt turning the pump the right way i spent weeks and alot of money replacing a whole cooling system just to find out my water pump was turning the wrong way,its easy to do i am sure you have change some things like no smog pump,a/c its easy to place the belt on the wrong way after modifying the orignal set up
 
You must log in or register to reply here.

Similar threads

R
Engine Fox body doesn’t run hot until I start driving
  • Rose5oh
  • Mar 17, 2025
  • Fox 5.0 Mustang Tech
  • 2
Replies
20
Views
1K
Fox 5.0 Mustang Tech Jun 7, 2025
limp
M
Resolved 1988 Foxbody - Overheating Summer
  • MDrisc
  • Oct 26, 2025
  • Fox 5.0 Mustang Tech
Replies
16
Views
727
Fox 5.0 Mustang Tech Jul 17, 2026
fasterthangas
F
D
Resolved Upper radiator hose cold??
  • dqureshi06
  • Oct 31, 2024
  • Fox 5.0 Mustang Tech
Replies
14
Views
2K
Fox 5.0 Mustang Tech Nov 11, 2024
limp
S
Progress Thread severe97's Project Thread!
  • severe97
  • Jan 27, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2 3
Replies
47
Views
2K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Feb 1, 2025
severe97
S
D
Engine how fast would an engine overheat with zero coolant
  • dqureshi06
  • Jun 29, 2024
  • Fox 5.0 Mustang Tech
Replies
11
Views
2K
Fox 5.0 Mustang Tech Jul 8, 2024
Mustang5L5
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?