cooling system flush

40cpe

40cpe

Well-known member
When I built my engine 6-7 years ago, I had the block dipped and cleaned really well, and had the original four-row radiator repaired, cleaned, and flow tested. I changed the coolant a couple of times since then and I'm in the process of doing it again. I've used distilled water/antifreeze each time. I can only see 4-5 flues through my radiator fill neck and one of them had a soft brown residue in one corner. I'm thinking I need to do a good flush. I read that modern flush chemicals aren't very effective. I have 2 questions: What is thought to be the best flush? and Is tap water OK for the flush and rinse? I'll drain it well before installing the distilled water and antifreeze.Thanks in advance for your thoughts.
 
I was a fleet mechanic for 30-years, we always just used regular hose water to back flush the radiator and block and we used it along with antifreeze to fill them back up. We did this every two-years and the radiators mostly stayed clean. We had a fleet of around 400 vehicles. We kept most vehicles around 15 years. We still lost some radiators which I suspect was due to small combustion leaks, there were some vehicles no matter how often we flushed them the coolant would quickly turn a rusty mess, for the other 95% of the fleet it worked pretty well. Now on my personal vehicles I always use distilled water and antifreeze, distilled water is cheap and at the grocery store so why not use it, changing it every two-years. Then I had a stroke and the cars have been sitting in the garage waiting to be worked on someday. I just don't feel up to it. The best thing is to flush them with a hose until they are clean and fill them back up with a 50/50 mixture of distilled water and coolant. Do this every two-years. Besides the radiator drain pull any block drains in your block if it has them to get "all" of the old water out of them. If you have and engine with a dirty coolant system, it is just about impossible to ever get it clean again like it was when it was new no matter how good you flush it, but if you change it since it was new or rebuilt every two-years it stays pretty clean.
 
I changed my antifreeze a few weeks back. I drained it, filled with water, ran it a few miles then drained it again. It looked a little rusty so I tried Rust-911. I left it in for a day and then ran the engine for a few minutes and drained it out and flushed with water. It was now clean and I filled with anitfreeze.The Rust-911, https://www.rust911.com/, worked well for me.
 
glennpm said:
I changed my antifreeze a few weeks back. I drained it, filled with water, ran it a few miles then drained it again. It looked a little rusty so I tried Rust-911. I left it in for a day and then ran the engine for a few minutes and drained it out and flushed with water. It was now clean and I filled with anitfreeze.The Rust-911, https://www.rust911.com/, worked well for me.
Click to expand...
I also used "Rust-911" on the Merc I put in my '51 Ford club coupe. The engine was on my run stand, so I spent more time and money than "glennpm" did (three complete flushes, leaving it in to "work" for 2 days), but I was very impressed how it came out. That was in 2016, with zero problems since. Here's a picture of the inside of the water pump cavity.
 

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tubman said:
I also used "Rust-911" on the Merc I put in my '51 Ford club coupe. The engine was on my run stand, so I spent more time and money than "glennpm" did (three complete flushes, leaving it in to "work" for 2 days), but I was very impressed how it came out. That was in 2016, with zero problems since. Here's a picture of the inside of the water pump cavity.
Click to expand...

Looks clean enough to eat off of :-)

Another thing to note is the jug instructions tell you not to exceed 180° F.
That is why I only ran it for a few minutes and got it up to about 140-150°
 
Big, big fan of Norosion's line of products. They make a flush that also etches and "primes" the cast iron inside the block. I run water and, when I drain it in winter comes, the water comes out as clear as it went in.

I highly recommend their products. Here is their website.

https://www.norosion.com
 
I’ve been cleaning rusty parts in my heated ultrasonic cleaner using RO water and Rust 911. It’s been working pretty well.

Last night I put in some of the rustiest emergency brake parts I’ve ever tackled, ran the ultrasonic for about 20 minutes, then left them soaking overnight. We’ll see how they look today!
 
I inquired about Norosion years ago. Once. They barraged me with mail every day and twice on Sundays for over a year. I’ve always been suspicious of products that needed such intensive advertising campaigns.
Edit: You know, I guess that statement kinda says a lot about me, right?
 
ford38v8 said:
I inquired about Norosion years ago. Once. They barraged me with mail every day and twice on Sundays for over a year. I’ve always been suspicious of products that needed such intensive advertising campaigns.
Edit: You know, I guess that statement kinda says a lot about me, right?
Click to expand...

I've tried it, and wasn't overly impressed. Also, I think it's way over-priced.

Maybe that's how they paid for all of the advertising you got.
 
tubman said:
I've tried it, and wasn't overly impressed. Also, I think it's way over-priced.

Maybe that's how they paid for all of the advertising you got.
Click to expand...

I sure agree on excessive advertising. When I see it, and not for long, I have the same thoughts about the cost being added to the product. Anderson Windows has flooded advertising here in Maine for the last year for example.

I did read about norosion on their site and it does appear to be very effective.
 
All my life I just used tap water for my antifreeze mix, but now here in Kansas the water is really bad so I have switched to distilled water. There is white crusty stuff at the top of the tubes, not sure of anything that will clean it. I was told by an old radiator guy to never use anything with acid in it as the acid will attack the solder joints
 
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