GunkRadiator Flush, HD, 22 Oz

Gunk radiator flush works very well it's a little bit of a pain to go through the process but when you're done your engines cooling system is clean and ready for antifreeze.

This product seemed to work very well on an 18 year old Toyota truck which had a previous owner who neglected maintenance. I flushed with this product and then did a "rinse flush" with distilled water two times thereafter. System is clean!

I think it did what it was supposed to do. The coolant in my taurus was brown and murky and the heater core was becoming clogged. the new coolant is staying clean looking and the heater works better now.

Used this product to do a full flush of a somewhat neglected cooling system. Seems to have got small black beads (rust pieces?) out but there are a couple of gotchas that you should be aware of.1. You will need to rinse with water at least three times after you drain this flush product from the cars radiator. Otherwise, white foamy residue will remain which- not clear to me- is okay to retain in the radiator long-term.2. If there are weak components in your cars cooling system, they will fail- my car's heater bypass hose developed a leak almost immediately after I used the product. I am not blaming the product - if anything it may have accelerated failure of a marginal component. But I mention it here since potential for such failure exists with this product.

Really wanted to like the GUNK Radiator Flush. But I received a substitute product.

After suffering the dreaded GM 3800 LIM gasket failure, my coolant was a cruddy mess. Even after replacing the gasket and manifold and several flushes by my mechanic, my radiator cap was still getting gunked up after a few thousand miles. So I bought this stuff and the prestone back flush kit. I flushed once with pure water, then added this, ran the engine for a few minutes, drained, refilled with water and ran that for a week (not recommended but I was replacing the water pump, all hoses, radiator and catch tank anyway). I did another flush and replaced the cooling components and refilled with Dexcool. A month after the work, my coolant is still clear orange. Thanks!

This flush removed all the deposits I saw in the coolant hoses prior to running it through. I had tried running a 20% citric acid solution prior and it didn't get nearly as much out as this product did.Only issue is that it is foamy. I needed to flush my system with water 3 times before it would no longer foam.

This chemical got the rust out of my father's Toyota 4Runner. However I would recommend to follow the instructions explicitly and use DISTILLED water to flush (last i checked its about 1.00$ a gallon at your grocery store), if you use hose water or any other filtered water the dissolved minerals in that water will promote rust and destroy your water pump. If you have a pretty dirty radiator fluid (looks off color, brown or you see rust) i would say you might need to run this product twice over a period of 2 weeks.