Evaporust Thermocure cooling system flush - Pontiac GTO Forum
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post #1 of 3 (permalink) Old 11-19-2017, 04:58 AM Thread Starter
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Evaporust Thermocure cooling system flush

Has anyone used or heard anything about ThemoCure? I see a few posts about Evaporust (same stuff), but not the CS flush.

I know it works well for cleaning heavy scale from blocks. After filling an engine block as best possible (heads were off) and letting sit two days, it cleaned scale down to bare metal. Afterwards, I had it hot tanked and HTing didn't do as good a job as Evaporust (shop wasn't so great though).

I've read one quart will treat 12 quarts, and a 69 with 4-row radiator (no AC) will be more than this so would need 1.5-2 quarts. Engine is out/dry so no problem of mixing it with coolant (can't do this), but I have other cars I want to use it in. I guess best is pull thermostat, use a T-fitting, and keep flushing and draining until water is clear/no green coolant. A youtube video from manufacturer just shows the guy draining the coolant from petcock (never works for me, I always have to pull lower hose) and dumping in a quart of this, then topping off with water, but this will leave a lot of coolant in the block .. maybe 4-6 quarts?

What happens if 1/3 of the coolant is still in? It's not as effective? If no one knows, I'll contact vendor and post back. I'm just curious if anyone has used this.

A few basics from reading reviews. It turns black (and smells rotten) when it works - dissolved rust will saturate the solution and lose effectiveness. It may be needed/best to do two treatments (after flushing first until clear) if CS is very rusty, as most are in old cars - I'd rather do two treatments because of needing to clear water flush/can't mix TC with AF. The stuff is non-corrosive so can be left in for a week or more, but it could freeze with winter coming up, so need to watch temps (GTO no problem in CA, but curious if using this will make my V6 GMC truck heater work better in MO [for which I've tried "everything"]). Then have to flush out Thermocure/rust residue before adding antifreeze.

I was planning to pull the thermostat and flush with a T-fitting on heater hose, while revving up some with petcock open until it runs clear. Should this be good enough, or is best to drive it a ways to get the lower block flushed good? (and I've heard a lot of rust particles can build up in lower block and will never come out without a good hot tanking)

Lastly, some guys say they flush the Thermocure from the engine with distilled water, which I don't think is necessary - seems a waste. I know to use distilled water to dilute full strength antifreeze. Maybe they do this so what's left in block is distilled water (seems excessive, but my 67 GP radiator rotted and I want to avoid any chance of this).

Summit has a good price on this. It's a bigger hassle than the usual cleaners, but does a better job.
Now thinking it might be good to use the acid/citrus based cleaner first to try to avoid using TC twice (two 2 quart flushes with ThermoCure is $80).
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post #2 of 3 (permalink) Old 11-19-2017, 11:09 AM
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I don't have any advice to offer but I've never heard of this stuff so appreciate your post about it....interesting.

Oh, and welcome to the forum!
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post #3 of 3 (permalink) Old 11-20-2017, 01:27 AM Thread Starter
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Thanks -good to get back to the GTO and this forum. Threw a rod in the 428 about 15 years ago and had to get the trans rebuilt (no reverse or third gear). Now getting a 400 set up. Had been busy with work, but now job ended so packing up all from CA and moving it to MO - need to get this car running to put on a trailer.

I'll call the Evaporust/Thermocure vendor, get some questions answered, and post back later.
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