Cooling system sealant

[94_SDV]

I have read a great many posts on here regarding coolant flushes and the powder/tabs to be used. Everyone talks about the Bars Leak and GM tabs, but the store I went to only had the Bars Leak liquid, which is not recommended. The only powder they had was Prestone, so I bought it. Has anyone tried this brand before?

[Dave S Texas]

I'd say it's probably ok to use. Any parts store that sells AC Delco should have the tabs (part #10-108)...less than a few dollars. The GM #3634621 tab will be at a GM Dealer.

[94_SDV]

I used the Prestone when I flushed the system today. As this is the first car I've had that requires sealant, can someone tell me if it's normal to have a bubbly substance at the top of the coolant, at the rad neck? I assume it's the sealant as it looks brown, it almost looks like a bubbly froth....

[Sevillian273]

Yes its normal. I use the bars leaks tubes and I get the same thing. You may also notice the surface bubbles in your overflow tank.

[HUF]

Wal-Mart has Bar's Leaks Golden Seal powder.

[79malibuonblocks]

why do you have to use sealent? I changed my rad and didnt add stop leak, I also had a plastic T break later and I lost all of my coolant, when I filled it up I didnt add any stop leak because I didnt know I had too. Whats the deal?

[94_SDV]

There's a label atop the rad on my 4.9 that says "this engine requires a sealant" or something along those lines. I don't know why it needs it, but it does. Someone more familiar with these engines can probably give you the answer as to why it needs it, but i added it as the label on the engine, and the endless posts on this matter in this forum, says it needs it.

[submariner409]

79malibu, Several middle/late 90's years of GM engines (and other manufacturers, too) called for a factory install of a Bar's Leaks product which comes in either tablet or powder form. The code number "12" is in the product ID. (Bar's GoldSeal IS NOT the GM recommended powder).

The idea was to initially seal and subsequently plug block casting porosity and nuisance leaks to prevent customer comebacks.

The idea has since been dropped. If your system is tight, don't sweat it. If you get paranoid obsessing over imaginary leaks in the middle of the night, the stuff won't hurt.

[HUF]

Originally Posted by submariner409

79malibu, Several middle/late 90's years of GM engines (and other manufacturers, too) called for a factory install of a Bar's Leaks product which comes in either tablet or powder form. The code number "12" is in the product ID. (Bar's GoldSeal IS NOT the GM recommended powder).

The idea was to initially seal and subsequently plug block casting porosity and nuisance leaks to prevent customer comebacks.

The idea has since been dropped. If your system is tight, don't sweat it. If you get paranoid obsessing over imaginary leaks in the middle of the night, the stuff won't hurt.

GM's tablets and Bar's Leaks Golden Seal powder is actually the same stuff (ground ginger roots) made by the same company.

[tallpat]

The reason is two fold the first is that the sealant is needed because of porosity of cast aluminum engine block. the second it helps prevent electrolsys between the cast iron heads and the aluminum block. I have heard horror stories about 4.1 in particular that the head bolts corrode due to dissimlar metal electrolsys and the head gasket blows at like 40k. because the owner did not use the powered sealant.

you MUST use it every time you flush the system I do mine every year in the spring. as we know if you overheat these engines you will damage the block and heads.