2001 Pontiac Montana Constantly Adding Antifreeze

Reader Question: Hi,

I have a question about:

Engine Block Sealer Additive Tips

I have a 2001 Pontiac Montana with 170,000 KM. I think the coolant is slowly going down in the overflow tank.

At what point would you suggest the above treatment? Should I take it in for a pressure test? From what I hear, the repair is about US$2,500 dollars.

Are there any side effects to doing this additive on a Montana Engine? I do not want to make things worse. Any updates on this treatment use with Montana engine would be appreciated.



Howdy David,

Definitely get a cooling system pressure test FIRST. You could have a simple external coolant leak, which the sealer will not resolve. Make sure your mechanic inspects the plastic overflow bottle for cracks and leaks as well; they are notorious for leaking at the seams.

You did not mention any common symptoms of a head gasket leak, which are:

1. Engine overheating
2. Engine oil in the coolant or coolant in the engine oil
3. Constant unexplained loss of coolant
4. White smoke out the tailpipe
5. Check engine light on the dash
6. Engine missing or running rough due to coolant on the spark plugs

I am unaware of any known issues with the Montana engine and this additive although I am not convinced you need to use it just yet.

Austin Davis

Posted in: Fluid Leaks

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