Mercedes Benz sell the citric acid like this for cleaning cooling systems - which works fantastic
the new jar below
would you prefer to buy this from Shahnawaz Ltd? - Its literally food grade citric acid - the same kind you buy at a karyana store / supermarket.
The other big daddy radiator and cooling system cleaner was sold by Prestone back in the day and also sold as GM genuine part - it was called Heavy Duty Cleaner, it was a single tall container with two ends, one end held a charge of oxalic acid and the other was basic washing soda for neutralizing.
It could clean completely mudded systems to a sparkly shine but required the person to be quite attentive too.
These newer bottles are made for DIYers who are doing it as placebo or treating a system with expired coolant (modern type) - not a system running with tap water for a decade. For the tap water scale and rust you need a HD cleaner which is not usually sold by such cos. anymore due to liability reasons as the new folks and will harm themselves or their car in the process. Back in time if you goofed up your job, you were held liable, nowadays people sue the brand for not telling them that its corrosive, dangerous etc etc.
The big boss cleaners from Ford (like their VC9) are very strong - but are not DIY freindly unless you are at level 10 out of 10 level of DIY work (10 meaning you can pull your own engine alone, fix it and stuff it back like factory install)
