Flushing rust/buildup from radiator, thermocure experience?

Exhumis · Jul 14, 2019

My 94 has the original radiator from what I can tell and it's starting to get rust and corrosion accumulation inside, no overheating issues yet. It's the metal rad. I'd like to do some preventive maintenance and get that scale flushed out before it becomes an issue. I'm aware I may spring a leak in the process but that's a risk I'm wiling to take vs a blocked and plugged rad. Anyone have a goto product or have any experience with thermocure?
If I do spring a leak I have a backup plastic rad that came with my truck.

BR3 · Jul 14, 2019

I've used it once on a 302. Worked great when used as directed. It's a chelation agent, so it can even be reused, and it totally safe. Took a very very rusty system and turned it clean with a little patience

Macrobb · Jul 14, 2019

One thing I did that sort of worked was to pull a radiator, flush it with a hose a few times. Then, I rigged up a flush "cycle" system going from a 5 gallon bucket -> hose -> water pump -> hose -> lower radiator inlet -> up through the radiator -> out the upper hose and into the bucket.

Started with water, then added a gallon of muriatic acid to it. So, somewhat dilute(muriatic is 30%, plus 4 gallons of water). Let that cycle for a couple hours, then drain and flush.

It got a bunch of looser stuff out, but didn't get these really hard white deposits stuck around the mouths of the channels. But, after I did that, I ended up using the radiator and... no leaks, no problems yet.

Exhumis · Jul 14, 2019

BR3 said:
I've used it once on a 302. Worked great when used as directed. It's a chelation agent, so it can even be reused, and it totally safe. Took a very very rusty system and turned it clean with a little patience

That's cool, wasn't aware it worked that way. May give that a shot.

lotzagoodstuff · Jul 14, 2019

+1 on muriatic acid, works really well but super caustic so be careful. I’m a big fan of laying the rad on its front side and filling it up with some diluted version, letting it sit, then flush carefully, repeat.

Good luck

BeastMaster · Jul 14, 2019

Here's a link for thermocure MSDS PDF.

https://evapo-rust.com/wp-content/uploads/2018/08/Thermocure-Safety-Data-Sheet-2018.pdf

Looks like it's diammonium phosphate. Probably good fertilizer if not too contaminated with glycol.

https://www.cropnutrition.com/diammonium-phosphate

I have had bad experience in the past about ammonia and copper reactions. In a refrigeration application. I am still leery.

Anyone used vinegar? Oxalic acid? Citric acid?

https://www.homedepot.com/p/Eco-Clean-2-lbs-99-6-Pure-Oxalic-Acid-Powder-OXALIC-2/306067769

https://www.amazon.com/bulk-citric-acid/s?k=bulk+citric+acid

https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4444435/Performed_the_Citric_Acid_Flus

Yes, it sure is tempting to use products marketed specifically for this, but I also consider there are other factors, such as profitability, marketing, who gets paid, possible lawsuits, etc, which have a strong influence on what gets offered to me.

I find its usually best to know what you are doing. And the science behind it. Marketers often want to sell me something with the most profit margin they can.

Flushing rust/buildup from radiator, thermocure experience?

Exhumis

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BR3

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Macrobb

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Exhumis

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lotzagoodstuff

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BeastMaster

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