Cleaning crud from inside bottom of block (cooling system)

[dozz302]

Hello, I have a motor I can run on a engine stand, what would be a good way to clean crud out of the bottom of the block where the water plugs are? I pulled water plugs (one on each side at bottom of block) and had to get a piece of wire to break thru the stuff to get what little coolant was in there out. Motor was built about 45 years ago, has hardly any miles on it but has always had antifreeze in it.  Stuff that cam out was like a thick brown gue. What will dissolve that stuff if I repeatedly put in and drain? Also any recommendations for coolant hose filters?

[Rory428]

If it was my engine, I would knock out all the core plugs from the sides of the block, and dig around the bottom, with a wire coat hanger and flush it out with a garden hose. Also try to snake a flexible magnet around the bottom of the water jackets. to pull out as much rust scale as possible. When I rebuilt my 428 a few years ago, I couldn`t believe how much crap was sitting in the water jackets.

[pbf777]

        If after a thorough degreasing and abrasive/shot blasting, the block is one which just still has lots of rust crap in water-jackets, flakes of rust falling out every time one rolls the block over, then we just surrender to the process of filling the water-jackets up with muriatic/hydrochloric acid and let it fizzle for a while, flush with water and inspect.  Another treatment may be deemed necessary, but if not, or just when you've concluded this endeavor, then treat with some baking soda slurry to neutralize and flush again with lots of water.   

        This of course is when working with a bare block, and disassembly may prove to be necessary if the block has a lot of trash accumulation.   

        Scott.

     

       

[dozz302]

Screw in freeze plugs so won't take out. OK now the acid solution is up the ally of what I was referring to. Engine won't be taken apart. Engine has always had antifreeze so there is no real rust just brown sediment at the bottom. No "flakes". What about engine foaming degreaser? A couple of cans in each side?

[cjshaker]

If you won't pull the freeze plugs, that's going to make it much more difficult, but understand why you don't want to go that route. If you can hang the engine from the bellhousing side, face down, with the water pump off, then a pressure washer, or even using the pressure part of a hose wand would do a bunch to flush out all the loose crap. Aim it through the pump holes and just spray at every angle you can towards the sides of the bores. Using a coat hanger like Rory suggested would really help also. Otherwise, it'll be a losing battle trying to get all the crud out of those small water drain holes.

I wouldn't want to use any type of acid if not tearing the engine down. I doubt it would be friendly to head gaskets, intake gaskets, any aluminum etc.

[dozz302]

Yes that's another idea.
I would never try and remove screw in core plugs. They won't come out without the risk of damaging the block. After being in for 50 years there in for good.