Product Review: Thermo-Cure cooling system flush.

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cruiser

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MoBros: Just thought I'd post a quick review of my first ever experience with Thermo-Cure cooling system flush. My 1974 Duster has a 1974 dated replacement 225 slant six engine that was installed in 1988 when my original slanty died. The replacement engine was sold as a rebuilt unit, so I assume that they did a complete flush and cleanout of the block prior to rebuilding it. I heard that Thermo-Cure is a pretty good product, so I thought I'd give it a try since it was time to change out my old coolant anyhow - and here are my results. First, I had to order a one quart bottle from NAPA. They don't sell it on the shelf, and it's a bit pricey - around $30.00. As per the directions on the container, I first blew all the old coolant out of my engine by removing the lower radiator hose and the drain bolt in the side of the block, then hooking up a garden hose to the flushing kit tee in the heater inlet line. With the engine running and the radiator cap off, I used the plastic deflector that came with the flushing kit to direct the coolant discharge flow away from my alternator. Once everything was clean and nicely blown out, I added the quart bottle of Thermo-Cure. The instructions tell you to leave it in for several days while you drive the car. I ended putting about 400 miles on the car during this period, which I felt was plenty of time to let the product do its job. After the engine cooled, I hooked up the garden hose to the backflushing tee, then opened the radiator drain **** and the drain bolt in the block. With the radiator cap removed and the plastic deflector in place, I turned on the hose and immediately a solid stream of coffee colored coolant came flying out. It actually looked like dark coffee coming out of the engine via the deflector, the block drain and the radiator drain ****. I was so captivated by this sight that I forgot to take a photo to post here! Anyhow, I let the hose blow everything out for about 15 minutes with the engine running. It took that long for all the crud in my cooling system to come out. Eventually, I had a stream of clean and clear water coming out of the radiator and drain ****, block drain and deflector. I completed the process by installing 6 1/2 quarts of Prestone II classic green antifreeze to create the perfect 50/50 coolant mixture that the FSM calls for. I also took this opportunity to thoroughly clean out the coolant reserve bottle and its supply line from the radiator. And yes, I mix my Prestone II with tap (not distilled) water and have had excellent results with no contaminant or calcium buildup in my original, re-cored copper and brass radiator. My city has a water softening system in our public water supply, so all that bad stuff comes out of the tap water before it gets to my house. In any case, my cooling system is extremely happy and keeps my motor right at 195 degrees all day while protecting against corrosion. So I'd have to say that I had very good results with this product and can recommend it, for whatever that's worth. Please feel free to add your comments if you have used Thermo-Cure. And no, I don't work for them - I'm just a guy who decided to try their stuff for the first time. Thanks, all!

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Nice looking car. What temp did it run at before, or did you se a reduction in operating temp?

I've seen what goes on in city water supply facilities, so I wouldn't trust them with a 10' pole. All distilled, all the time for me.
 
Nice looking car. What temp did it run at before, or did you se a reduction in operating temp?

I've seen what goes on in city water supply facilities, so I wouldn't trust them with a 10' pole. All distilled, all the time for me.
No, the car has a 195 degree thermostat and it doesn't run any cooler. I didn't expect it to run any cooler after the flush - I just wanted to get 34 years of crud and rust out of my engine block. I've previously restored my cooling system with all new components (thermostat, stat housing, all hoses, water pump and drive belt, heater core, all clamps and recored and rebuilt radiator as mentioned earlier). And yeah, I can see your point about using distilled water. All I know is that I've been using tap water from my home for the past 34 years and have never noticed any contaminant buildup in my cooling system. Maybe I'm just lucky but I've had excellent results with tap water and Prestone II (or the equivalent NAPA antifreeze).
 
ThermOcure did a very good job removing hard to clear rust from two of my cars including my Dakota with it's fairly well known rusty coolant issues.
 
You might check the MSDS sheet to see if it lists the secret sauce. It seems the Prestone flushes today are much wimpier than in the past. I bought 10 lb of citric acid on ebay and use 1 lb in the radiator with tap water (after flushing), run for about a week, then flush many times to remove all acid. I think that is what the older Prestone flush used. People swear by many acidic products like lemon juice (above) and even Coke (supposedly ph of 3). To derust small parts, I leave in a jar of EvapoRust, but too pricey for a car's cooling system. I also use Phosphoric Acid (Concrete Etch at Home Depot), sometimes after EvapoRust to remove more or at least convert it to black oxide in pits. Most derust sprays have that. But, I think risky to use on aluminum (timing cover in small-blocks, water pump in slants, ...).

Worst clogging I've had is in my 1996 Plymouth Voyager. I recall using "extended-life coolant" at one time, before the horrors of Dex-Cool was known (and not marked thus on jug). I started getting dark corky-like stuff floating at the top of the radiator, which might have been reactions with remnants of green coolant. After flushing and refilling with green, I later got a lot of rust (left streaks on my concrete driveway when flushed), so maybe some fight between acids still ongoing. I finally got a new radiator and flushed the block alone and brown crud was still coming out. Installed a screen in the top hose to try to catch remainders to not clog the new radiator. All my other vehicles I've changed to Evans Waterless Coolant, so no such concerns. The various coolants with varying chemistries and funky colors today will spin your head.
 
First time I flushed the heater core n our first 67model, I didn't use a flushing Tee. I simply took the 2 hoses off the engine a draped them over the fender. Garden hose in one heater hose until water ran clear. A coworker walked out there and said now reverse direction of flow. Yep, nasty water again. I let it run until it ran clear and reversed direction of flow again and got dirty water again. I repeated this procedure like half dozen times before I got clear water both ways. Best I could decipher, a heater core has places in it that a flushing Tee in one hose would never remove. Anyway she went from very little heat to run you out of the car heat.
 
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