H8eraide Marine Descaler Concentrate- Descaling Engine Flush - A/C Flush - 100% Biodegradable - 1gal - Strongest & Safest - Non-Corrosive- Phosphate-Free - Raw Water Engine Flush

I used this for a Volvo D4 260 raw water cooling cleanout. I purchased the boat last year and there was not much that the previous owner did to maintain it.... and I knew that. Overall ran fine last year, but this year I noticed something...coolant temps were moving around when over 3000rpm. Supposed to run at 185 and would jump to 196 then 200 if I stay under power.... 205 and it would go into protection and back off the power by itself. That said, I took off the end plate of the turbo heat exchanger..... and it had some crud in it, but not too bad. I could only imagine what the rest of system looked like. I did pull the impeller as it had to be changed anyway and I used a circulation system with the H8eraide 1:1 with water as per the instructions. I did flush my system with fresh water first then got this ready.... I let it run one direction for 90-min then the other direction for another 90-min. The liquid did get darker the longer it ran. Afterwards, I flushed the whole system with about 60-gallons of fresh water (both directions) and then reassembled everything. I did pull the end of the turbo heat exchanger off again... WOW was it clean. Not a trace of anything in it and looked almost new. Reassembled and then went out for a test run. Ran it at full throttle for 30-min and it never once blipped over 185. Perfect. Recommend... absolutely. For my application I ended up using 2-1/2 gallons to make a total of 5 gallons of solution to circulate. I could have done it with 2-gallons, but I forgot to close off the hose for the stuffing box... my fault.

Best calcium/lime descaler. Tried acid free descalers and found this to be the best. One brand that cost twice as much did very little in removing scale. Did not use acid descalers due to it being harmful to most steel metals.

Not as great as I expected. I let it run through for 4 hours and didn’t clean out as much as it could have.

works well, cleaned out the engine and HX nicely. I wish they sold their AC/refrigerator salt water flush here too...

Easy to use, non toxic, biodegradable. It works!

Run thru my outboard cooling system for 2 hours. Worked well. No more engine overeating alarm.

No difference internally that I can see.

Great product. Descaled my partially clogged heat exchanger