MAJOR Cooling System Sludge

[Deleted User]

I started to cleaning out the block section of the cooling system today. I have MAJOR SLUDGE in the bottom of the block. 1/2" to 3/4" in the front by cyl 1 & 2. I used a straw to check it like a "core sample."

What is the procedure for removing this while keeping the engine in the car, not contaminating the oil system and without buying a bunch of special equipement? I am willing to remove the freeze plugs (just tell me where to purchase new 2" ones) just tell me how best to do it.

Marconi

dig out what you can, flush with hose and when it runs clear drain the block as best you can. Replace freeze plugs with corks or whatever you can find that works also the water passages in the top of the block. Then fill with white distilled vinegar and let sit for several days to a week. Flush out with hose and replace freeze plugs, etc. You should be able to get these at a NAPA store and by all means use brass ones, not steel.

[Deleted User]

Thank you, Marconi. That was my basic plan only I was going to use Pro grade CLR or Iron Out. I am looking for a way to use the drain on the rear of the block and a pond pump to keep circulating the cleaner.

wano1949

If you can't find large enough corks for the freeze plugs, they make an expandable rubber freeze plug that you plug into the hole and tighten a bolt in the center to expand and make the seal.

You can put in and remove when you finish and install regular metal plugs.

These are what you would use if you had a freeze plug leaking and you couldn't get to the area on an engine to drive a new one in. Kind of a last resort, but they hold up pretty good.

Good to carry one in the tool kit for an emergency fix.

Aaron D. IL

I pulled out the freeze plugs on mine and masked the engine compartment and blasted it out with a power washer until it ran clean and replaced then with DORMANN-555 2" plugs. It worked fine for me... I don't think any amound of flush solution will get it all when it's caked i the clock like that.

[Deleted User]

Thank you for listing the part number. That helps in the search.

Marconi

CLR will work fine and fast, but vinegar is a heck of a lot less money and you have a little control over the time it takes. Gets cost effetive when you consider that the block will probably hold at least a gallon of the stuff!