Thermocure to remove rust from coolant system

[944TurboS]

Has anyone ever tried using "selective chelation" with products like Thermocure to remove rust from the coolant system?

[dr bob]

This looks like an interesting product, but is it really applicable to our aluminum-engine cars? A look at the MSDS tells me nothing, with an ingredients list that includes only "Proprietary" and some water. I'm sure it's safe since so many cars have aluminum radiators, but don't know any products that would create a chelate of aluminum oxide. Or whether I want to remove a protective aluminum oxide layer anyway. [scratches head where hair used to grow...] I don't see any testimonials that include aluminum-engine cars, via any of the mainstream sellers.

Think about the things that clog our cooling systems, and carefully choose the cleaning products that successfully remove the bad ones without chewing on the aluminum in the process. Rust (iron oxide) doesn't make it to the list of things I worry about, mostly because there are no iron or steel components in regular coolant contact. I see more problems with folks who use hose water vs. distilled in their coolant mixes, use incorrect coolant products, and from the effects of changing coolant formulas without proper prep. Same for cooling system cleaners that aren't flushed out completely.

I'm no expert on these products or their detailed chemistry. I've been cautious about many 'new technology' products, and ask the same questions you do about others' experiences before I adopt them. In a somewhat related case, I swapped to a new and fabulous 'universal' coolant in a relatively new iron-engine car in the mid 1990's. A year later I had the heads off to replace head gaskets, and there was a slew of major litigation over that product and compatibility issues. I have no interest in being the guinea pig for such things if I can avoid it. Especially when there are known-good options so readily available. With careful chem choices, the biggest cooling system issue I've had in almost 30 years of 928 ownership (same engine and cooling system materials as the 944) has been a sticky thermostat. I scoped the bottom of the radiator at that time, where any debris usually ends up, and it was completely clear. The engine gets fresh coolant every two to maybe three years, with only distilled water in the mix. I was in denial about the thermostat, but replacing it solved the symptoms. We learn.

Let's see if your question gets more informed responses. I'm always in learning mode.

[944TurboS]

I collected some rust from the two (originally zink coated ?) tubes as well as the flanged water tube connecting to the heater valve in the 951 cooling system. I am replacing all three but still finding rust on the inside of the hoses. I hope someone has more info.