Fix it right. Stop leak clogs other things that ain't posdabe clogged!

Sometimes they work, sometimes they don't.  Sometimes they cause no
problems, other times they block up the heater core so it can need a
flush later.  It likely needs a flush anyway....

On something that old I would try it, it can hold some wicked cracks.
When I use it I always 'expect' to need the heater core flush later, so
I only get surprised when I don't need to....

Intermittent leak can be the pump seal though.   Stop leak won't help
that.  You might want to see if you can run your finger under the snout
of the waterpump after running for enough to warm it up and shutting it
down.  If you feel moisture under there, he needs a pump.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos:  Non members can still view!
Jan/06 http://www.imagestation.com/album/pictures.html?id=2115147590
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"...very expensive special vehicles that are supposed to be 100%
available"?  What does that mean?

Oh, and don't use stop leak.  That's the same basic product as "Doesn't
Stop Leak", "Over Heat" and "Stop Heat".  The remediation required
after using stop leak will likely cost more than a proper repair would
have.

Toyota MDT in MO

"Cheap fix"
"Hey I'll just toss in a can of stop leak and fix it, cheap." Buy $3.00
can of "Stop Leak" and pour it into the radiator. Start the engine and
drive around for a while to "fix the leak". While driving around you
decide it is a little chilly out and turn on the heat. Drive home and
park the car. "Hey look at that it isn't leaking, GREAT, and it was
CHEAP." Next day you check the coolant level and add some since the
engine has now cooled down and isn't leaking. You jump in the car, Fire
it up and drive down the road. You turn on the heat and wait, and wait
and...W A I T some more. "Huh the heater was working fine yesterday.. I
Know it has some air in it because the coolant got a little low." The
next day you still don't have heat, and you notice that the engine seems
to be running hotter than before. Half way to work you suddenly see the
temperature spike up fast and steam starts coming out from under the
hood. "Dammit, Well I guess something must have blown apart" So You call
the tow company who comes out and takes you back to a shop. There they
start looking it over and discover that the radiator core is half
plugged by the "Stop Leak" They pull it and replace it with a new one.
You then mention that the heater wasn't working very well, The shop
tries to flush it but that doesn't work and they ask you if they should
replace it. You say "Sure I need heat" They tear apart half of the dash
and replace the heater core. They also replace both of the molded rubber
lines since they are pretty ratty. Put everything back together and send
you out the door.

Total bill for that "cheap fix":

Radiator: $215.00
Upper and lower hoses: $46.00
Heater core: $48.00
Heater steel lines: $73.00
Heater rubber lines: $27.00
Coolant: $16.00
Thermostat& Gasket: $12.00
Radiator cap:$10.00
(all prices listed are from online sources NOT what you will likely pay,
those WILL be higher)

About 5 hours labor at $85.00(+)per hour

Plus Tow bill : $100.00 (probably low unless your insurance covers it or
you know the operator)
Two days off from work because the car is in the shop.

Five days later the water pump starts weeping because the crap in the
"Stop Leak" wiped out the seals.......

The stop leak works sometimes.  It doesn't fix the problem, but it delays
things for a while.

Don't think you won't have to replace the radiator, because you will.  But
with the stop-leak you might be able to put off replacing it for another year
or so.

If you use a good quality product, it won't do any harm.  But it won't really
fix the problem, just hide it for a while.
--scott

I'm going to guess this mechanic also sells radiators.  The stop leak
may work for a while, but it may also plug up the radiator completely.
Get the problem fixed correctly with a new radiator.

My guess is it wouldn't because due to the age of the vehicle and your
description as intermittent, I'm guessing there's some general
corrosion and wiggling in the area, which stop leak doesn't do well
with. On the other hand, if it's like a pinhole in an otherwise solid
piece of metal like when you catch a rock in a radiator fin, it works
great.