Packard Forum Index » V-8 (1955-56)

Years ago there was a product like Owen Dyneto is talking about, "Borden's #7 cooling system cleaner", an acid powder you add to a dry engine, fill with water, run until hot and then empty, put in neutralizer, fill and back flush clean.
that stuff worked pretty good, but was no match for father time and past owners of much older cars. When you can scrape it out with a screwdriver it's bad, and is going to affect how the system cools.
If you take a block (and heads, etc.) out for rebuilding and cleaning is part of your process (hopefully) the hot tank at the auto parts store isn't going to do enough, you need the "Chem Strip" process where they submerge the parts in a solution (Alkaline? Owen?) and put electrical current through the solution. That process gets out all of the rust, and leaves you with a spotlessly clean block, inside and out. Some shops have a glass bead attachment they hook up to the freeze plugs, they seal off all of the plugs and let the beads fly, and apparently that does much the same.
It is my experience that when it is that thick the "wonder in a can" products only do so much.

As always, I think Mr. PB is right on target. Using a chemical flush every year or two was probably sufficient to keep a cooling system in good condition for perhaps the useful life of the engine until such time as a rebuild was required. But when neglected to the point of large accumulations of salt and rust buildup, no "snake oil" in a can is going to reverse the ravages of time and neglect.

For those of us that live in areas where we keep antifreeze in year-round, a reasonable interval in my opinion to flush the system and replace the antifreeze is perhaps every other year. Remember that though ethylene glycol doesn't loose it's freezing point depression properties over time, the corrosion inhibitor packages in it do have a finite life time.