It did the job, after another product did not.
We used this product twice on a 2009 VW Jetta 2.5 L engine (they are known for clogging up crazy like), but it loosened up so much stuff and junk out of the heater core once used the first round, I've never seen so much stuff come out of a heater core!  We ran it for a bit and it didn't overheat, so we put two more bottle in again and got a just a little bit more.  So far so good, no more overheating.  We found an invoice in the glove compartment, and whoever owned the car before had another shop also used another radiator product first and it was still overheating, they put in new fan assembly, and thermostat chasing the overheating issue.  They finally sold it because of the overheating issue.  We will be using this one again first time when we have a coolant issue  & overheating.  This product does a super cleaning of whatever might be in a cooling system.
Rating: 5 stars