coolant sludge in block.

[Billythefoo]

I have a L28 block without a head on it that i am planning on using in my 240. but when looking down on the top of the motor i can see where the old coolant has turned into a nasty orange rusty type sludge. i was wondering what the easiest way the flush that out of the block is? should i just turn it upside down and flush it using a hose or what? thanks in advance.

[waynekarnes]

most of the crude is usually down at the lower hose adapter.

 

had same issue with a 73 i bought that had been parked for 12 yrs.

 

this is what i did with the engine in the car. suggest you put your block at that angle.

 

remove the adapter. i used a piece of metal bent into a hook shape to remove as much as i could get to inside the block and in the general area .

 

remove thermostat. put the housing back in place. put upper radiator hose in place.

 

take garden hose, shove it into the upper hose. if you want, you can use duct tape to seal the garden hose inside the upper hose.

 

at spigot ( faucet ) turn water on about half way.

 

this will blow most of the loose crude out of the block.

 

after about 5 minutes, turn water all the way on.

 

run water another 5 or so minutes.

 

turn water off. let drain.

 

put the lower adapter back in place. put lower hose on. seal the end of lower hose.

 

at local auto parts store, get some coolant flush. dump it in the upper hose. if air temps are cold ( winter ), boil some water on the stove ( couple gallons ) or microwave. per directions on the container, add the appropriate amount of water, down the upper hose.

 

block in garage or out of the cold, let it set for couple days. every once in a while, using a a large RUBBER mallet, hammer HARD on the block.

 

after couple days, drain the cleaner ( remove lower hose and adapter - the adapter is bolted to the block ).

 

run hot water through the block.

 

pour it in the upper hose.

 

let it run out the bottom of the block.

 

grab the garden hose, repeat what you did before using the cleaner.

 

this should clean about 75% or more of the crude out of the block.

 

the rest you can get out once the engine is in the car and running.

 

good luck, wayne

[Billythefoo]

Thanks this should help.

[lammbn]

you know if you really want to get it all out and be sure that everything is all good in both the oil and the water passages the best thing to do is get it hot tanked. it doesn't cost that much but it really gets them cleaned up good. it even gets a lot of rust and scale off the block and out of the coolant passage ways. i just had mine done, and with a little shopping around i ended up paying about $35 for the hot tanking part on just the block. about $50 was the average of everywhere i called. I also had the block magnafluxed and the head sonic tested and cleaned, all together it ran me $140. which i am more than happy to pay for the piece of mind that everything is good to go.