If you have would you say it was successful, & what was your process?? I'm talking a good and and running engine that needs interior cleaning more than just flushing and back flushing.
You would have to neutralize it after running it thru the motor, then flush real good. Evaporust has phosphoric acid in it I think. Years ago there was some radiator flush that was 2 parts. First part flush, second neutralizer. I haven't seen anything like it for a long time though.
Evaporust and it's ilk ("Rust-911", "Metal Rescue") are not acids of any type and need no neutralization. It works through a process called "chellation", which is some sort of ion exchange process that I have been trying to get a handle on for years with little luck. I have run "Rust-911" through a '51 Merc I was using and it turned out well. I ran it through, flushed it (to remove any chunks) and did it a second time. Here is the result. (I should probably have let it go longer, but this was a good running engine and the stocker in my '51 Ford was making a funny noise.) Also, there was a poster "Old Henry" on "The Ford Barn" who did a fairly well documented test soaking crusty water pumps in various stuff who also had good results with it.
I stand corrected. I was thinking of a different rust remover. Evaporust does make cooling system cleaner I just learned from their web site. I may have to try that in my truck. Evaporust sounds a little like Safest Rust Remover. I have used that stuff and it works great.
The Evaporust Thermocure isn't a five minute process for sure. THERMOCURE™ - Cooling System Rust Remover & Flush | EVAPO-RUST® (evapo-rust.com) I'd be wanting to wait until I was sure it wasn't going to freeze again unless the car spends nights in a heated garage.
I did with CLR Did good. removed the stat, poured in the CLR, added water and ran it for several minutes. then drained and flushed out with water. Looked like new cast iron on the inside.
About ready to do something to an old in car block that just has the worst rust factor - always turning the green anti-freeze to rust color in a short period of time. Have tried cleaning it out back flushing -front flushing and have had the tank cleaned as well. About ready to pull the motor out and all the freeze plugs and do a clean out.
I've used vinegar with fairly good results. Once on a 4cyl diesel and a Plymouth flathead. Didn't make it look new, but did remove a lot. could have got it all if I had repeated the soak and rinse a couple of more times.
Electrolysis does a great job, I do it often on rusty blocks and it is amazing on how much stuff gets pulled out. Block needs to be degreased first. Lots of Youtube videos on the subject for reference. 55 Gallon Plastic Drum 1 box of Arm and Hammer Baking Soda, fill with water 2" above block, sit block on some 2x4s in bottom of drum Older Battery Charger with adjustable amperage - I use 10 amps on 12 volts Daisy chain some clean steel strips with Romex wire ( at least 6 anodes, connect to hot side of the charger - DO NOT LET ANODES TOUCH THE BLOCK!) Ground lug on the block with a piece of Romex wire to ground to with the charger Will produce hydrogen bubbles so do in well ventilated area, typically 12-24 hours to clean up. Initial Setup After Washing Soda and starting the current After about 4 hours The rust stuck to the anodes and there was a bunch of sediment in the bottom after dumping the water (not pictured).
Not that you could do this to an engine currently in use but another option if you are starting from scratch.
Here's what I have done, and it worked very well. I had a running driving car that always ran hot, and I could tell that there wasn't good flow through the radiator, and I assumed that the block was crusty too. The paint was all nicely finished, including a bunch of painted bolt heads, so I really didn't want to pull the radiator out, or pull the motor apart. So I pulled off the lower radiator hose, and let all of the antifreeze solution drain out. I bought two 10-ft lengths of inch and a half rubber hose at the lumber yard, and I connected one of them to an electric submersible pump on one end, radiator on the other end, then I set the pump in a 5-gallon bucket. The other inch and a half hose got connected to the water pump outlet on the vehicle, with the loose end sitting inside the 5-gallon bucket. Then I poured water into the bucket and turned on the pump so it was circulating water through the radiator, the water pump, and the block. I changed out the water a few times until it was running clear. Then I started mixing in sulfamic acid powder. I don't remember exactly how much I put in, but there was some instructions somewhere. I think I put in a couple of cups. That's sulfamic acid really cleaned it up good. It is especially good at dissolving mineral deposits. I let that circulate through everything for about 2 or 3 hours. Then I rinsed it all with clear water, then neutralized it with a solution of baking soda and water. Then fresh water again. After that the car ran perfectly cool, right on the thermostat setting even in hot weather.
The problem with electrolysis is that it works "line of sight" only. It can't "turn corners". I would suspect this quality makes it a less an ideal method to clean the inside of the block.
Current Honda factory procedures calls out to use CLR to clean heater cores before replacement. I use it and works great on the white crusty deposits. Freed up a stuck heater valve for me. Pull the thermostat and drain the coolant. Fill up with water and CLR. Run the engine just until it gets warm. Then let it sit 30 minutes or so. Then run it again and let it sit another 30 minutes. Pull the bottom hose to drain the CLR out. Stick a water hose in the top of the rad and flush it out. Pull the heater hoses and flush out the heater core. Pull the top Rad hose and stick the water hose in and flush out of the bottom Rad hose. Replace the thermostat, hoses and coolant. Done.
Thanks tons for all the replies and info on my question. No overheating problem, (knocking very, very hard on wood), just want the system as clean as possible.
Not to hijack this thread, but in response to stillrunners post, what he describes is a classic symptom of exhaust gas getting into the cooling system. Could be a blown head gasket or that unmentionable thing that sometimes happens to cast iron.
I ran a flathead with a gallon of CLR and water in it, flushed it out, and did it again until it ran clear.
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