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

Leak be gone?

  • Thread starter Thread starter Grandmaster
  • Start date Start date Mar 20, 2004

Grandmaster

New Member
Dec 7, 2002
374
0
0
Monticello, Arkansas
Mar 20, 2004
#1
  • Mar 20, 2004
  • #1
I have a pretty fast coolant leak but i cant find it and its driving me crazy. I've parked the car and watched for drips, put something under it and checked later, and i cannot pinpoint where the leak is. I've seen producs that you're supposed to add to the coolant system which "finds the leaks" and plugs them (so i guess it gunks them up). Is this stuff safe? For the life of me i cant find this leak, and its fast, i can fill er up and the light'll be back on in a day. Any suggestions? THANKS!
 

NKau

Founding Member
Dec 15, 2001
1,346
0
37
Jefferson, WI
Mar 20, 2004
#2
  • Mar 20, 2004
  • #2
Might be just me, but I don't trust stuff like that. Who knows what else it will "plug up" besides your leak....... better just to take care of the problem the right way.
 

Grandmaster

New Member
Dec 7, 2002
374
0
0
Monticello, Arkansas
Mar 20, 2004
#3
  • Mar 20, 2004
  • #3
NKau said:
Might be just me, but I don't trust stuff like that. Who knows what else it will "plug up" besides your leak....... better just to take care of the problem the right way.
Click to expand...

Any idea how i should go about finding the leak?
 

NKau

Founding Member
Dec 15, 2001
1,346
0
37
Jefferson, WI
Mar 20, 2004
#4
  • Mar 20, 2004
  • #4
You say it's a fast leak, and you can't seem to find drips under the car? Might be one of things where it's leaking slowly when parked, but worse when running. After a full day/night of being parked, I would still think you should be able to find some evidence of dripping. Does the coolant level seem to go down a lot faster when driving as opposed to when it's parked?
 

Grandmaster

New Member
Dec 7, 2002
374
0
0
Monticello, Arkansas
Mar 20, 2004
#5
  • Mar 20, 2004
  • #5
I think it leaks most when running. I can park it and watch and i wont see the leak. But yes, they'll be like a broad damp spot under it whenever i come back out to it. Its like i need to watch it for hours just to see it or something. I've left it running and watched to no avail. Guess i'll try again and just watch until i see something. So is there any other way it would be losing coolant besides a leak, just in case? thanks.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
34
129
Mar 20, 2004
#6
  • Mar 20, 2004
  • #6
trace the cooling system. few places to check: under the water pump (weep hole), around hose clamps, the coolant lines on the TB, heater lines, and heater core (cant really check it, but look for damp carpet or a layer of yuck in the inside of the windshield), thermostat housing and the radiator. there are others, but those are the bigger ones i can think of.

clean the areas up real well. top up the coolant and start it up. look at all the areas you cleaned for leaks (fresh coolant running around). you may need to be under the car, so be careful and all of that.
that is the best i got. they do make dyes you can put in the system. i have not used them.
also i do not like the sealers you describe. they also plug passages, and if you happen to have some air in the system, the stuff will plug the passage where the air is. not good.
this is just my thinking and what i would do. good luck.
 
1

10HoleLX

Member
Mar 6, 2004
257
0
17
Southern California
Mar 20, 2004
#7
  • Mar 20, 2004
  • #7
Grandmaster said:
I have a pretty fast coolant leak but i cant find it and its driving me crazy. I've parked the car and watched for drips, put something under it and checked later, and i cannot pinpoint where the leak is. I've seen producs that you're supposed to add to the coolant system which "finds the leaks" and plugs them (so i guess it gunks them up). Is this stuff safe? For the life of me i cant find this leak, and its fast, i can fill er up and the light'll be back on in a day. Any suggestions? THANKS!
Click to expand...

GO to Auto Zone auto parts or equivalent and rent a coolant system pressure tester.

When you pressurize the system with this tool it will cause the leak to show up.

You can test the system when engine is cold or hot.

But of course be carefull when openinng the cap when engine is Hot.

Good Luck
 

NKau

Founding Member
Dec 15, 2001
1,346
0
37
Jefferson, WI
Mar 20, 2004
#8
  • Mar 20, 2004
  • #8
10HoleLX said:
GO to Auto Zone auto parts or equivalent and rent a coolant system pressure tester.

When you pressurize the system with this tool it will cause the leak to show up.
Click to expand...

I like this man's thinking. HISSIN50 also mentioned some good places to visually inspect. The seal between the thermostat housing on the intake is a really common place that just kind of begins leaking on it's own; you will notice coolant dripping down onto the waterpump if that's the culprit. I would also look at the coolant overflow tank; those can crack, or the hoses running to them can too.
 
8

89 Saleen#455

Founding Member
Dec 29, 1999
519
5
39
New England
Mar 20, 2004
#9
  • Mar 20, 2004
  • #9
You can also trace the leak using ultraviolet dye and an Ultraviolet light. Add the dye to the cooling system let the car run for about 5 mins. Turn the lights out in the garage or wait until it gets dark outside (the darker the better). And take the ultra violet light and scan the engine bay for the bright colored dye. Climb under the car and do the same thing there. Tracing a coolant leak using the U/V dye is a breeze! You will also be surprised at how many of your coolant hoses have trace levels of the dye at the very ends. Extremely useful tool! Will also work with Oil leaks and A/C leaks when used with the proper dye.
 

Look Its Aaron

Your car looks like it came straight from Mexico.
Founding Member
Nov 18, 2001
2,634
0
48
Fontana, Cali
Mar 20, 2004
#10
  • Mar 20, 2004
  • #10
Do not rule out a minor busted head gasket.
 

roush 97

New Member
Aug 28, 2003
86
0
0
Illinois
Mar 20, 2004
#11
  • Mar 20, 2004
  • #11
I had trouble finding mine a couple weeks ago, it turned out to be the weep hole in the water pump. It seemed to leak worst soon after the car was turned off.
 

Grandmaster

New Member
Dec 7, 2002
374
0
0
Monticello, Arkansas
Mar 20, 2004
#12
  • Mar 20, 2004
  • #12
thanks for all the tips, i'll start checkin it out probably tomorrow.
 
You must log in or register to reply here.

Similar threads

P
Engine Mysterious coolant leak at back of engine
  • palerider94
  • Jan 18, 2026
  • Fox 5.0 Mustang Tech
Replies
1
Views
196
Fox 5.0 Mustang Tech Jan 19, 2026
AeroCoupe
V
Engine Coolant Leaking?
  • vinzo
  • Jan 26, 2025
  • Fox 5.0 Mustang Tech
Replies
7
Views
497
Fox 5.0 Mustang Tech Jan 26, 2025
2000xp8
2
Electrical mayhem
  • 2000ElectricGreen
  • Mar 13, 2026
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
2
Views
287
1996 - 2004 SN95 Mustang -General/Talk- Mar 24, 2026
2000ElectricGreen
2
M
2001 v6 heater return pipe leak question
  • mnky99
  • Nov 11, 2025
  • SN95 V6 Mustang Tech
Replies
1
Views
265
SN95 V6 Mustang Tech Nov 11, 2025
mnky99
M
Electrical 88 EEC Injectors batch firing ?
  • Dustin 86GT
  • Dec 8, 2025
  • Fox 5.0 Mustang Tech
Replies
10
Views
465
Fox 5.0 Mustang Tech Jan 8, 2026
gkomo
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?