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

Fox what thermostat to run in the summer

  • Thread starter Thread starter mattys91gt
  • Start date Start date May 19, 2022
  • Tags Tags
    radiator thermostat
Prev
  • 1
  • 2
First Prev 2 of 2

hoopty5.0

mechanicus terribilis
15 Year Member
Dec 14, 2010
7,788
6,940
214
SW Houston
May 22, 2022
#21
  • May 22, 2022
  • #21
Mustang5L5 said:
I mean that’s typically what happens. Modern fuel injected engine is designed to run around 200-210 degrees. That’s enough to (almost) boil water.

These engines run efficient at that temp range. I don’t mean fuel economy, but in terms of driving off moisture and contaminants from the oil, proper engine clearances and other factors that contribute to a long-living engine.
Click to expand...
I dont know why I didnt know that they were meant to operate around that range, I thought it was cooler.

I seem to remember someone pointing that out to me recently and it didnt even register. I guess I was operating under the assumption that I need it to run as cool as possible because when I add AC back in I know it's going to add a few degrees
 

mattys91gt

Active Member
Feb 3, 2022
391
26
38
Plymouth Massachusetts
May 22, 2022
#22
  • May 22, 2022
  • #22
hoopty5.0 said:
I dont know why I didnt know that they were meant to operate around that range, I thought it was cooler.

I seem to remember someone pointing that out to me recently and it didnt even register. I guess I was operating under the assumption that I need it to run as cool as possible because when I add AC back in I know it's going to add a few degrees
Click to expand...
I don't even think my ac works would love it to since it's going be 90s today
 
Reactions: hoopty5.0

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,264
17,950
224
Massachusetts
May 22, 2022
#23
  • May 22, 2022
  • #23
hoopty5.0 said:
I dont know why I didnt know that they were meant to operate around that range, I thought it was cooler.

I seem to remember someone pointing that out to me recently and it didnt even register. I guess I was operating under the assumption that I need it to run as cool as possible because when I add AC back in I know it's going to add a few degrees
Click to expand...

It’s one thing if this is a race motor you operate for one season and tear down. Not enough time to do do any sort of damage before it gets pulled apart anyway.

But yeah, for modern EFI engines too cold can be a bad thing.

Of course the downside is that the underhood temps tend to creep up, but there are ways to control that via venting or a big fan. A lot of times this excess heat soak is generated by the exhaust and has nothing to do with the coolant temps.
 
Reactions: limp, KRUISR, mattys91gt and 1 other person

KRUISR

10 Year Member
Apr 16, 2015
1,822
929
143
May 22, 2022
#24
  • May 22, 2022
  • #24
I have a 180 thermostat but my e-fans don't kick in until 200. So when it is hot out the car runs pretty steady around 200.

If I am cruising on the highway on a colder day the temp will stay lower. Been running this way for 5 years with no issues. I get 21/22 MPG on the highway
 
Reactions: Shakerhood and General karthief

hoopty5.0

mechanicus terribilis
15 Year Member
Dec 14, 2010
7,788
6,940
214
SW Houston
May 22, 2022
#25
  • May 22, 2022
  • #25
Mustang5L5 said:
It’s one thing if this is a race motor you operate for one season and tear down. Not enough time to do do any sort of damage before it gets pulled apart anyway.

But yeah, for modern EFI engines too cold can be a bad thing.

Of course the downside is that the underhood temps tend to creep up, but there are ways to control that via venting or a big fan. A lot of times this excess heat soak is generated by the exhaust and has nothing to do with the coolant temps.
Click to expand...
Well, I can always put the 180 stat back in if it stays too cool. But, that hasn't been a problem lately, haha
 

mattys91gt

Active Member
Feb 3, 2022
391
26
38
Plymouth Massachusetts
May 22, 2022
#26
  • May 22, 2022
  • #26
was I asking in here about my 83 gt hood scoop that was put on backwards to act as a ram air for the carb and I wanna use it for heat to escapes and I plan on putting on my 91 gt I made a template to figure out where I need to drill and cut not sure if anyone has done this would love to see pictures sorry if it's the wrong topic
 

7991LXnSHO

wanna catch the space herp
10 Year Member
Sep 1, 2010
7,387
2,745
194
Kearney, NE
May 22, 2022
#27
  • May 22, 2022
  • #27
mattys91gt said:
was I asking in here about my 83 gt hood scoop that was put on backwards to act as a ram air for the carb and I wanna use it for heat to escapes and I plan on putting on my 91 gt I made a template to figure out where I need to drill and cut not sure if anyone has done this would love to see pictures sorry if it's the wrong topic
Click to expand...
Probably should have started your own thread, but oh well.
I added a factory scoop to my 79. I measured and marked with masking tape where the air cleaner stud was straight across to the fenders. I removed the air cleaner housing and stud, and found where that line centered on the hood. I had a thick poster board pattern of the scoop with a circle of the outer edge of the housing needed to be for clearance. Then I drilled the holes for the studs and cut a big circle out of the hood with a jig saw. The circle was over four layers of masking tape and the saw foot was taped for scratch avoidance.
As early Fox hoods were easier to find than now, so I just almost chickened out, and kept my shorts clean.
It looked stock unless it was next to a GT and you looked very closely. For a backwards install, I’d follow the same process. The clearance hole could be smaller for vent holes.
I’m not sure where my uploaded pics went.
 

KRUISR

10 Year Member
Apr 16, 2015
1,822
929
143
May 22, 2022
#28
  • May 22, 2022
  • #28
7991LXnSHO said:
Probably should have started your own thread,
Click to expand...
He did. I guess people aren't responding fast enough so he is asking in other threads.
 

mattys91gt

Active Member
Feb 3, 2022
391
26
38
Plymouth Massachusetts
May 22, 2022
#29
  • May 22, 2022
  • #29
KRUISR said:
He did. I guess people aren't responding fast enough so he is asking in other threads.
Click to expand...
I wasn't sure if I asked in here or another thread I apologize I'm in no rush just looking for ideas and the right way it should be done and my bad this is my first mustang I've never worked on one before
 

mattys91gt

Active Member
Feb 3, 2022
391
26
38
Plymouth Massachusetts
May 22, 2022
#30
  • May 22, 2022
  • #30
7991LXnSHO said:
Probably should have started your own thread, but oh well.
I added a factory scoop to my 79. I measured and marked with masking tape where the air cleaner stud was straight across to the fenders. I removed the air cleaner housing and stud, and found where that line centered on the hood. I had a thick poster board pattern of the scoop with a circle of the outer edge of the housing needed to be for clearance. Then I drilled the holes for the studs and cut a big circle out of the hood with a jig saw. The circle was over four layers of masking tape and the saw foot was taped for scratch avoidance.
As early Fox hoods were easier to find than now, so I just almost chickened out, and kept my shorts clean.
It looked stock unless it was next to a GT and you looked very closely. For a backwards install, I’d follow the same process. The clearance hole could be smaller for vent holes.
I’m not sure where my uploaded pics went.
Click to expand...
I'll post mine in a few I just have the pic of the hood it came off of
 

Attachments

  • Screenshot_20220509-090152_Gallery.webp
    133.5 KB · Views: 119

Shakerhood

20+ Year Stangneter
Oct 28, 2004
3,357
209
114
Ohio
May 24, 2022
#31
  • May 24, 2022
  • #31
I have had a 180 in mine for over 20 years, still works great.
 
Reactions: General karthief and mattys91gt
Prev
  • 1
  • 2
First Prev 2 of 2
You must log in or register to reply here.

Similar threads

M
2001 cobra coolant crossover delete
  • Mike3
  • Jul 5, 2026
  • SVT Tech Forum
Replies
4
Views
141
SVT Tech Forum Jul 12, 2026
Mike3
M
Fox Help
  • 93fox85
  • Mar 22, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
5
Views
222
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Mar 23, 2026
Noobz347
Engine Themostat
  • Mindseye007
  • Jan 30, 2026
  • Fox 5.0 Mustang Tech
  • 2
Replies
21
Views
767
Fox 5.0 Mustang Tech Feb 1, 2026
86HO5.0
8
M
Resolved 1988 Foxbody - Overheating Summer
  • MDrisc
  • Oct 26, 2025
  • Fox 5.0 Mustang Tech
Replies
16
Views
708
Fox 5.0 Mustang Tech Jul 17, 2026
fasterthangas
F
B
84 turbo fan not working.
  • bdub_mkg
  • Jan 29, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
8
Views
305
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Feb 2, 2026
AeroCoupe
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
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?