C2: Cooling system flush

[Dan Pepper]

After recently removing my intake to fish-out a loose pushrod lifter seat, I noticed a layer of rusty gunk in the head water passages. My '66 BB runs very cool, so I'm not concerned about a clogged radiator, and the original heater core seems to work fine - without leaks.

Question: Should I drain and refill the cooling system with one of those anti-rust/corrosion additives to clean out the rust build-up? I bought a bottle of Prestone flush - drain old fluids, add water plus this additive - then run for 100 miles or so , afterward flush and refill with H20 & antifreeze. By doing this, will I run the risk of exposing holes plugged by rust in the heater core and rad? Should I leave well enough alone? Or flush-a-way?

[Jim T.]

Re: C2: Cooling system flush

Don't have the best solution, but you could remove the drains on the side of the block with the intake off and the bottom radiator hose from the water pump and inject water into the water jacket area and try and remove the accumulation of stuff in the coolant system through the bottom drain blocks. I would tape off the bottom radiator hose outlet so the draining stuff would not migrate through the water pump initially. Catch the stuff coming out of the block drains and you could be amazed at what comes out. I bought a 63 SS in 1967 when I lived in San Diego. The heater would not blow any heated air from the heater core. The heater core was full of sludge, completely blocked but easily flushed by removing the heater hoses.

[Brian J.]

Re: C2: Cooling system flush

Dan,
I just flushed out my 66 BB using a Prestone back flush kit. To install the kit you need to cut one of the heater hoses, and install a tee( provided in the kit). Then you hook up a garden hose to the tee and the old coolant and crud comes out the radiator fill cap. When you are done you just cap up the tee with a cap ( in kit), and do the same thing the next time.
Good luck,
Brian