Radiator Flush

works good

A+

This radiator flush worked exactly as intended and was simple to use. The instructions were clear, and the product mixed into the cooling system without any issues. After running it through and draining, the coolant passages were noticeably cleaner, and the old buildup was flushed out effectively. I noticed an improvement in cooling performance afterward, with the engine temperature running more consistently. It is a straightforward solution for routine maintenance or before replacing coolant. The bottle contains enough for a complete flush, and the price is reasonable compared to having a shop do the service. For anyone looking to maintain their cooling system and keep it running efficiently, this is a reliable and effective product.

Used BlueDevil Radiator Flush on my buddy’s truck. The coolant went from muddy brown to see-through in one afternoon. Never had an overheating issue to begin with, just wanted it clean. Minus one star because while the coolant looks great now, the inside of the reservoir still looks like it’s been chain-smoking for 20 years.

Did the job! Make sure to replace your thermostat afterwards.

Wow! This stuff works much better than I expected! I just purchased an '85 Cadillac Seville as a restoration project. I decided to flush out the radiator after I drained the system in order to replace all the radiator hoses, heater hose, thermostat, etc... I figured that it couldn't hurt even though the antifreeze that I drained looked bright green and clean. I filled the system with the bottle of Blue Devil and water from the garden hose. I left it in the system for about a week and drove the car about 150 miles (in the summer with no chance of temps dropping anywhere near freezing). I drained the radiator and was shocked that the water that came out was dark brown and there was brown sludge in the overflow tank! I also ran the heater on high during that week to make sure the coolant was flowing through the heater core. At first, I couldn't even tell if the heater worked. By the end of the week, it was blowing fire! I drained and refilled with straight 100% water 3 more times and each time, the water drained was dirty until the 4th time when the overflow tank didn't have a layer of brown sludge on the bottom and the radiator drained out clear water again. I then refilled with Prestone antifreeze 50/50 mix and the GM tablets they recommend. I have much better piece of mind knowing that all that corrosion and sludge was cleaned out of the cooling system, probably saving me from overheating and costly repairs down the road! Blue Devil really cleaned out and opened up coolant passages in my motor! I'll be using it on all my cars now!

doesn't seem to have much cleaning power

Auto flushing

Seems to.have done the job