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

3g alt=hotter engine temp

  • Thread starter Thread starter flashback87
  • Start date Start date Jul 14, 2010

flashback87

Member
May 18, 2010
345
4
19
Cleveland, OH
Jul 14, 2010
#1
  • Jul 14, 2010
  • #1
hey guys, after i installed my 3g my engine temp is a little hotter. it was right about 190ish before i did the swap and now it is between 198-200. would the alternator cause this?

i have an after market temp gauge and i am running a taurus fan on high at all times.

thanks for the help.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
34
129
Jul 14, 2010
#2
  • Jul 14, 2010
  • #2
Did you have the Taurus fan before the 3G swap?

Is there any issue with the belt routing or did the alt pulley diameter change drastically?
 

f8tlfiveo

My wife likes my spool and blow-off valve.
Aug 8, 2007
1,585
102
64
Lancaster, PA
Jul 15, 2010
#3
  • Jul 15, 2010
  • #3
I wouldn't think so... Wonder if the change in pulley size makes the water pump turn slower.. It's only 10 degrees I wouldn't worry about it..
 

flashback87

Member
May 18, 2010
345
4
19
Cleveland, OH
Jul 15, 2010
#4
  • Jul 15, 2010
  • #4
thanks for the replies,

my tarus fan was on before the 3g install and that is when it was running a little cooler. i have always been running under drive pullies and when i did the 3g install the new alt pulley was about the same size as my u/d alt pulley so i did not swap them(i left the 3g alt pulley on)

i did have to go with a shorter belt since the original was squealing like crazy when i did the 3g swap. the new belt is only about .5 an inch smaller and it is routed the same.

any other help or advise would be greatly apreciated.
 

NIKwoaC

中國製造
15 Year Member
Oct 31, 2006
5,525
943
214
Chengdu Province
Jul 15, 2010
#5
  • Jul 15, 2010
  • #5
As long as the WP and crank pulleys stayed the same size, WP speed shouldn't change. Belt length wouldn't cause a change in speed of anything either. The only thing that would change if the alt pulley diameter changed is alt speed, but it sounds like that didn't change either.
 

flashback87

Member
May 18, 2010
345
4
19
Cleveland, OH
Jul 16, 2010
#6
  • Jul 16, 2010
  • #6
any other ideas or is this just normal. i feel like i finally got my car to run at the right temp but ever since the 3g it has been getting hotter but it has been staying right at 200.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
34
129
Jul 16, 2010
#7
  • Jul 16, 2010
  • #7
An alt should not cause the car to run hotter, so it's not normal. Either it's coincidence with warmer ambient temps or something else changed.
 

90mustangGT

I felt sorry for girls because
Founding Member
Jan 15, 2002
2,773
17
89
Dallas, GA
Jul 18, 2010
#8
  • Jul 18, 2010
  • #8
Mechanical or Electrical temp gauge?
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,813
234
Dublin GA
Jul 18, 2010
#9
  • Jul 18, 2010
  • #9
If the secondary power ground (engine to body ground) is bad, the stock electric temp gauge reading will be incorrect. The engine to body ground is also the ground for the electric temp gauge.

The secondary power ground is between the back of the intake manifold and the driver's side firewall. It is often missing or loose. It supplies ground for the alternator, A/C compressor clutch and other electrical accessories such as the gauges.

Any car that has a 3G or high output current alternator needs a 4 gauge ground wire running from the block to the chassis ground where the battery pigtail ground connects. The 3G has a 130 amp capacity, so you wire the power side with 4 gauge wire. It stands to reason that the ground side handles just a much current, so it needs to be 4 gauge too.

The picture shows the common ground point for the battery & extra 3G alternator ground wire as described above in paragraph 2. A screwdriver points to the bolt that is the common ground point.

The battery common ground is a 10 gauge pigtail with the computer ground attached to it.

Picture courtesy timewarped1972


Correct negative battery ground cable.
 
You must log in or register to reply here.

Similar threads

M
Resolved 1988 Foxbody - Overheating Summer
  • MDrisc
  • Oct 26, 2025
  • Fox 5.0 Mustang Tech
Replies
16
Views
988
Fox 5.0 Mustang Tech Jul 17, 2026
fasterthangas
F
T
Electrical Brown Connector #31
  • ta66
  • Jul 26, 2026
  • Fox 5.0 Mustang Tech
Replies
2
Views
203
Fox 5.0 Mustang Tech Jul 30, 2026
ta66
T
M
1996 GT Speedometer electrical nightmare
  • moon96gt
  • Oct 7, 2026
  • SN95 4.6L Mustang Tech
Replies
2
Views
165
SN95 4.6L Mustang Tech Oct 17, 2026
CAMTWO1070
Resolved Got Too Hot!!!
  • PonyGTrider
  • Apr 27, 2025
  • Fox 5.0 Mustang Tech
Replies
7
Views
742
Fox 5.0 Mustang Tech May 6, 2025
PonyGTrider
Resolved 93 Mustang 5.0 - Cranks but does not start
  • dan50
  • Jul 18, 2026
  • Fox 5.0 Mustang Tech
Replies
6
Views
444
Fox 5.0 Mustang Tech Jul 18, 2026
dan50
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?