CARGO is good stuff ... its glass/silicone with copper dust ...
this stuff hates coolant ... !!!
1.flush radiator well with garden hose , top up go for drive , turn heater on, let cool down and flush again.
2.fill radiator with water , shake bottle of car go and put whole bottle in radiator, put cap on.
3.start engine and go for drive with heater turned on until engine temp goes halfway by sitting in traffic
4.leave in for a day or so of stop start driving , then empty radiator and leave cooling system without water/coolant for 12 hours.The stuf will dry and seal inside.
5.add coolant and distilled water and run engine to remove air from system, thats it your done.
Cargo wont seal if you have coolant in the system , adding coolant after its sealed is ok.
It does not sayt on bottle to leave car dry for 12 hrs but on their website , Cargo is Aussie made
if your radiator has not been flushed for a while and you add that stuff can cause blockages .. so a good flush with garden house does wonders.
I got a small leaking inlet manifold and timing cover , adding bottle cargo once a year works good , if leaks bad than add 2 bottles