Anyone got suggestions on how
they have in the past been able to
seal tiny coolant system leaks?

I have had a small leak at what i thought was
the thermostat housing on my 1995 Magnum V8 Ram,
but after two tries to unsuccessfully fix it "down in the hole"
including using a snake video borescope,
yesterday i tore down the front of the engine
by removing the accessory bracket that holds the
alternator and air conditioning
in order to see every thing more clearly,
and redid all five possible leak sources...
Two temperature sensors,
the heater inlet hose,
the thermostat housing ( this time with Right Stuff and no paper gasket)
and the bypass hose.

Before putting everything back together,
i borrowed a radiator pressure test kit from O'Reillys Auto Parts
and pressurized the empty system and non running engine with air to 16 psi,
and then painted all the joints with soapy water
looking for the bubbles indicating leaks.

The good news was that
none of the stuff i had just redone
showed any leaks this time.
( the prior pesky leak was probably the heater hose nipple)

But the system would not hold
a steady 16 psi like it should have.

16 psi
would decline to
12 psi in
37 minutes.

Much more painting of other joints in the cooling system
finally showed that there was a
tiny leak in the timing chain cover gasket
at the top driver side corner.

Your suggestions for
simple cheap and easy fixes?

Yes,
the engine now has
198,000 miles
and probably needs a replacement for its OE
timing chain and
water pump
anyway.

It still has the unusual NPG coolant
without any water in the mix (all propylene glycol)
but i am thinking of draining it out as
$35 per gallon
makes any leak expensive.

in the semi trucks i work on the owner likes a product called Dike its available from heavy duty shops, seems to work well but thats just a bandaid.

head gaskets ok?

intake gaskets are APITA sometimes to get it to seal on an intake R&R.

does any water trace show up in the oil,crankcase,dipstick or tube?

the intake bolts only torque to 144 inch pounds which = only 6 foot pounds on the wimpy bolts.

you just cant torque down on the bolts like an old LA intake when the gasket would weep.

I had to do it 3x when I fixed the plenum pan gasket. by the way,is your plenum gasket leaking? maybe time for a intake R&R with all new gaskets.

I found the same leak on the t-cover but on pass side top corner.

I would agree if it has 198,000 miles on the stock chain it is well over due.

I would add a t-chain tensioner from the v-6 mopar engines while you are in there.

it is a little bit of a job,but when I done the 2 I had,i did the t-chain replacement along with the plenum pan gasket intake R&R. took a full 8 hrs.

makes it alot ez-er if you know the 6 bolts will let you swing the alum bracket,a/c comp,alt, out of the way as a unit without breaking down the a/c lines.

well my second job was ez-er faster after I had the leaning curve on the first one.

No secret, Alumiseal.

At 200K miles you're not driving much farther without taking it all apart anyway. So a Band-Aid will do just fine.

I have to laugh, I'm also using a propylene glycol/ethylene glycol mixture in my '64Dog, it's about half green Prestone and about half RV water system antifreeze, $3.49 at my local Wally World for the 50/50 mix. It needs some real antifreeze to lubricate the water pump and do the anti-corrosive bit, but it is safe to 50 below. The color also looks bad, the green and pink don't mix into a pretty color!

R.

ANY of this stuff plug-up the heater-core ?

I had not heard of Dike.

It got 6 good reviews on Amazon.

http://www.amazon.com/Dike-Temporary-Radiator-Stop-Leak/dp/B002HIB3GI

Homepage at Conklin

http://goo.gl/QpNSO

Sample quote

Key Benefits

Stops leaks in radiator in seconds
Seals internal leaks, preventing antifreeze and water from seeping into the engine
Helps gaskets seal better
Will not block small passages in the coolant system
Works with all antifreezes
Note: If the cooling system is filtered, the filter should be removed or bypassed when using Dike.

Less than 4 gallon systems

For best performance:

First flush radiator with Radiator Flush
Premix 1 pint of Dike to a minimum of 1 gallon water/antifreeze blend, add to radiator
Fill radiator with water/antifreeze blend to manufacture specifications

Would it be crazy
to pull a modest vacuum
on a mostly empty cooling system,
then "paint" some full strength leak fixer like
Alumaseal, Justice Brothers, Bardhal or Dike
on the external spot where i know
at least one tiny seep is?

As a hot cooling system
cools down to air temperature
it naturally pulls a slight vacuum.

For cripes sake just pull the cover and replace the gasket. For 10.00 you can get a gasket set and for 26 more a timing set. The crap sealer band aid will cost as much as the gaskets.

The implication that i am too lazy to spend the hours to do a job in the best known manner for long term reliability is incorrect,
i am,
and was raised that way by father and grandfather.
(It is deadly to cut corners in mining for reasons of laziness)

However,
the chance to safely experiment and
gain new knowledge on older equipment
that will soon be rebuilt anyway,
is also valuable,
both to me and
other pickup owners.

It is part of the American spirit and in line with
"Knowledge is Power"
way of going through life.

I once bought a cast iron sign that said:

Why is there never time to do things right the first time,
But always time to do things over?

And screwed it over a doorway at a workplace.