Which stop leak additive

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Why not do a pressure test and see where the leak is? Free rental from AZ or similar. Clean your engine first.

Those tablets are a band aid.

I've seen too many sludged up systems especially in the heater core resulting from their use. Dexcool which was common in your era and tabs together is a double whammy.

Do it right.

Your truck is about as easy and cheap as it gets to replace WP or radiator. If you screw up the heater core, that's a different story.
 
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GM used to and probably still does put the tabs in every new car. They do not plug heater cores. It used to be common to flush and change AF, then have a minor leak. Lots of times on the radiator header tank seal. I just put the tabs in again, no more comebacks.

Rod
 
I am thinking about using a tube of Barr's leak powder for preventive maintenance in my son's 2003 Monte Carlo SS 3800 V6 engine... Yea or nay??? 100K miles on original gaskets with no sign of a coolant leak. I do a drain and fill with fresh coolant every year.
 
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The Pressure test is typically a con job used by the second hand car industry to prove that you haven't got a coolant leak.

Take car that is losing 1qt of coolant a week to the dealer, they snap the pressure tester on it, get you to read the pressure, make you a cup of coffee, go back a half hour later, and show you that it is "within limits"..."bugger off".

If it's a leak on the neck, where the cap screws on, it leaks air, leaks down quickly...if it's a coolant leak, it leaks slow (1,000 times slower, water is 1,000 times denser than air).

Best time to see the leak is when the block is up to pressure, but the thermostat hasn't opened, cracks and gaps between hoses and necks are at their widest, and you might see a single drip...if it's sweet, it's coolant.

Things I've used.
* R16 cracked block, where they put a head bolt boss adjacent to a stiffening rib, used silver sealant (powdered metallic cottonny stuff)...took weeks, sealing from the tip of the crack bck to the bolt boss.
* Came out of MacDonalds one day, and saw a stream of green pee out the grille, where a tube had pinholed...Bars leaks, tin, the one full of soluble oil and rat droppings got me back to town, 40 miles for a recore and flush.
* Nissan's heater core, GM tabs.
 
Originally Posted By: Shannow
The Pressure test is typically a con job used by the second hand car industry to prove that you haven't got a coolant leak.

Take car that is losing 1qt of coolant a week to the dealer, they snap the pressure tester on it, get you to read the pressure, make you a cup of coffee, go back a half hour later, and show you that it is "within limits"..."bugger off".

If it's a leak on the neck, where the cap screws on, it leaks air, leaks down quickly...if it's a coolant leak, it leaks slow (1,000 times slower, water is 1,000 times denser than air).

Best time to see the leak is when the block is up to pressure, but the thermostat hasn't opened, cracks and gaps between hoses and necks are at their widest, and you might see a single drip...if it's sweet, it's coolant.

Things I've used.
* R16 cracked block, where they put a head bolt boss adjacent to a stiffening rib, used silver sealant (powdered metallic cottonny stuff)...took weeks, sealing from the tip of the crack bck to the bolt boss.
* Came out of MacDonalds one day, and saw a stream of green pee out the grille, where a tube had pinholed...Bars leaks, tin, the one full of soluble oil and rat droppings got me back to town, 40 miles for a recore and flush.
* Nissan's heater core, GM tabs.



Certainly not a con job. I'll agree it is not valid all the time, but in 90% of the cases it is a good test.
 
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