Chevy Impala Manifold Seal Fix

[FrankP]

I was somehow losing antifreeze from my coolant system in a 2000 Chevy Impala. I assumed it was a leaky seal.
I did a Prestone back flush system after using a radiator cleaner.
I then put in "green" fluid instead of the Dex Cool since I read it is the culprit of lots of cooling system problems.

Before adding the fresh radiator fluid, I put in two bottles of Subaru Coolant Conditioner (250 ml)

1000 miles later and counting fingers crossed there is no noticeable loss of coolant anymore!!!

 

[sciphi]

Could be the radiator cap. My Buick LeSabre started losing coolant, turned out to be the cap couldn't hold full pressure anymore. It took about 1000 miles of driving since the car had sat for about a year before the leak manifested itself. The new cap was about $8, IIRC.

 

[onion]

What engine?

If it's a 3100 or 3400, keep a close eye on those lower intake gaskets. They WILL fail at some point... regardless of what coolant is in there.

If it's a 3800, you gotta keep an eye on the lower intake gaskets, the seals where the upper manifold joins the lower manifold, AND around the throttle body. These are woefully common leaks. Probably not as pervasive as the 3100/3400 problem... but still way more common than it ought to be.

 

[Drew99GT]

On the 3800 series II the main culprit is the EGR stovepipe - aka the upper nylon intake manifold.

 

[FrankP]

Its a 3400 engine