Liquid Intelligence No. 243

Radiator Stop Leak Kit

The strongest and safest radiator fix on the market today.

Particle dissolving technology, never blocks passages
Seals holes to 0.50mm, cracks to 0.60mm
Treats up to 10 standard cooling systems
The strongest and safest radiator fix available

Radiator Stop Leak Kit

Liquid Intelligence 243 seals leaks in radiators, heater matrixes and cooling systems, then dissolves the particles left over, so it never blocks radiator flutes, heater matrixes or coolant channels.

A radiator core cut open after a traditional stop leak: its flutes almost entirely blocked by wet, bloated cellulose particles — A traditional stop leak: the leftover particles blocked the flutes

A radiator with its top tank removed after using 243: the flutes clear, with a few particles still dissolving, circled in red — After 243: clear flutes, with a few particles (circled) still dissolving

Thirty minutes of engine operation is all it takes to seal a leak: holes up to 0.50mm, and slits and cracks up to 0.60mm. The seal can last for years.

It mixes with coolant, water, or water with a corrosion inhibitor, and is also recommended with waterless coolant. One 400 gram container treats ten standard cooling systems or five large ones.

Where to use it

243 repairs leaking radiators, hoses, heater cores, Welsh plugs, water jacket cracks and head gasket seepage, in vintage, classic and modern vehicles. It's also used in light and heavy commercial vehicles, road haulage, earth-moving equipment, cranes, heat exchangers, diesel generators, forklifts and farm machinery.

The only fix professional mechanics recognise for a cooling system leak is a proper repair. When a workshop repair isn't possible, for one reason or another, 243 is the next best option.

How it seals without blocking

A traditional radiator stop leak is, in essence, a foreign contaminant. It may seal the hole, but 99% of its sealing particles are left over in the cooling system, where they can plug cooling passages, radiators and heater matrixes and cause overheating. 243 seals the leak and then dissolves what's left.

1. The particles travel to the leak

Close-up of 243's coated metal particles

243 is a blend of coated, dissimilar metal particles (magnesium, aluminium, brass, copper and bronze) from 10 to 400 microns, with synthetic resin sealers. The particles are light enough to stay in suspension in the cooling system until the coolant carries them to the leak.

2. A solid seal forms in the breach

A dense, solid cluster of 243 particles bound together by hardened resin

The particles are forced into the breach with the escaping coolant and block it, while the resin sealers slowly react and congeal around them. The resin hardens into a reinforced, dense, solid particle cluster inside the breach: a seal with a history of lasting for years.

3. The leftover particles dissolve

A few remaining 243 particles, scattered and dissolving

The particles still circulating after the leak is sealed dissolve away. The metals have different electrode potentials, so when two particles come close together in the coolant they form an electrochemical cell, one acting as the anode and the other as the cathode. Over a couple of weeks the reaction dissolves the less noble particles, leaving very little of the original dose. That's why 243 won't block heater matrixes, radiator flutes or coolant channels.

Instructions/How to Use 243

An open container of Liquid Intelligence 243 powder with its measuring scoop

Add one spoonful of 243 for every 5 litres of radiator water. A full 400 gram container treats 50 litres.
Run the engine: thirty minutes of engine operation is all it takes to seal a leak.

Delivery: AusPost, Australia-wide from Minchinbury, NSW.
International: AusPost International. New Zealand at checkout; elsewhere, ask us for a quote.
Made here: Formulated and made in Australia.
Support: Free phone help, 7am–7pm, seven days.