1998 Blazer has Exhaust gas in coolant
 

Personally, I would determine where the leak is (probably head gasket) and fix it the right way.

As for the products you ask about try getting the manufacturers user manual or instructions.
It all depends on the severity of the leak. Usually it's not possible to tell where it is leaking into the water jacket but in most cases it's on the head gasket.

Try to find the manufacturers recommendations on the products you ask about such as these:

http://www.goss.com.au/assets/Upload...nformation.pdf

https://barsleaks.com/gaskets/dealin...ad-gasket-fix/

I agree with Tom on the real fix but the it's becoming expensive. Minor leaking may be cured by these products.
A leaking head gasket also means water may go the other way and fill a cylinder or seep in and cause corrosion, rust, etc.
Unfortunately that usually means pulling the heads, new gaskets, even the need for machining or a new head.

Time to pull the heads, its about 15 dollars for a pair of Fel-Pro headgaskets and about 16 for headbolts. Good luck.

I would not recommend the use of any sealing goo. Can make a real mess of things. Pull the heads and also have them inspected for cracks.

Thanks for all of the great input.
I went with the Bar's Leaks HG-1 Worked as advertised.

I hope, for your sake, that it continues to work.

Awe man thanks but it's not a life or death situation

No, I'm sure it isn't. It's just that, in my experience, those fixes tend to fail spectacularly at the most inconvenient time, when I'm as far away from home or civilization as possible, lol.

I used the same stuff on my blazer when I purchased it two years ago knowing that it had a small head gasket leak. It lasted about 2 months, and when I didn't expect it, the head gasket failed and what an inconvenience that was as I was many, many miles from home.

I thought it would last a few thousand miles until I decided on my new engine.....I thought wrong.

It's a quick/temporary fix only.

BTW, I had to replace my radiator and heater core as that crap sludged everything up.