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Question for "Tester" - My son's 1999 Pontiac Grand AM

Low Coolant light comes on and liquid disappears from overflow tank. The car over heats. Heater also does not work. We spent over $600 a couple of years ago for a head gasket replacement, I think.

If we use the Sodium silicate, do we pour it into the overflow tank with water or coolant? I don’t see a radiator cap on top of his radiator??? Can someone help

Well…I’d answer but I’m not Tester :wink:

Doing something like sodium silicate would be a last resort band-aid attempt for head gaskets on cars that aren’t worth fixing. It may or may not do any good and even if it worked would almost always be a very temporary thing.

But either way, why are you assuming that you have a bad head gasket? Has the cooling system been pressure tested? There are many ways to lose coolant and several reasons that you could lack heat. There are also ways to find out for sure whether or not your head is leaking. So you really need to start by actually finding out what the problem is.

If, for whatever reason, you decide to use sodium silicate I would search for Steel Seal’s website and follow whatever instructions they give. Or stop and an auto parts store and read a bottle.

Add it to coolant reservior when the engine is cold and top off the reservior. Start the engine and idle the engine @ 2,000 RPM’s for ten minutes.

This is not very temporary repair. I treated one vehicle for a blown head gasket with sodium silicate over a year ago, and the vehicle is still being driven. This repair can last two years and longer.


Tester, I’m not Tester, either; but, I’m confused. You say to, “…add to coolant reservoir…and top off reservoir”. Are these two reservoirs different? If the stuff, any stuff, is added to the over-flow bottle, it won’t, necessarily, EVER be drawn into the radiator and engine cooling system. Coolant, or other stuff, is only drawn from the overflow bottle after the engine heats, and then, cools. The drawing occurs DURING the coolant/engine cooling period. New physiks?

This vehicle has the pressure cap on the coolant reservior, not on the radiator. Whatever is in the coolant reservior is going to mix with the coolant in the radiator.


Do I top off the reservoir with coolant or water?
Sorry for all the little questions.
Thank you so much.

Top it off with coolant. That way when the leak stops their’s still a 50/50 mix of coolant.

Why do you want to add stop leak?? Have you had the system pressure tested to make sure its not something simple like a hose clamp not tight enough??