Does radiator stop leak actually work?
For the leaks it's designed for — minor seeps and weeps from the radiator, hoses, gaskets and water pump — yes, it seals at the leak point as the coolant circulates. It won't fix a major crack, a failed head gasket showing white smoke or coolant in the oil, or a split hose; those need mechanical repair. For a small, slow leak it's an inexpensive thing to try before a workshop bill.
Can I still drive with a coolant leak?
A small weep where you top up occasionally can usually be driven on short-term while you treat it — but watch the temperature gauge, because a coolant leak can become an overheat that warps the head. If the level drops fast, the car runs hot, or you see steam, stop and don't drive until it's sorted. For a minor leak, sealing it early with Forte Radiator Stop Leak avoids the risk.
How much does it cost to fix a coolant leak?
It depends entirely on the source. A weeping hose or minor gasket seep is cheap — sometimes just a bottle of Forte Radiator Stop Leak. A radiator, water pump or head gasket replacement runs from the low hundreds into four figures with labour. For a genuinely minor leak the additive is the cheapest first step; for a major one, it's mechanical repair.
Will it block my radiator or cooling passages?
No. Forte Radiator Stop Leak is specifically formulated to remain suspended in the coolant during normal circulation and only react at the point of a leak. It will not deposit in or block coolant passages, radiator tubes or the heater matrix in a healthy cooling system.
Is it safe for aluminium engines and cooling systems?
Yes. Forte Radiator Stop Leak is safe for all cooling system materials including aluminium engine blocks and radiators, rubber hoses, plastic expansion tanks and water pump seals. The conditioning chemistry actually provides additional corrosion protection for aluminium components.
How long does it take to work?
Minor leaks may begin to reduce within the first heat cycle. For established leaks the seal builds progressively over several heat cycles — typically 2-5 days of normal driving. Monitor the coolant level over this period. If the leak does not reduce after a week of normal use, the leak may be too significant for additive treatment.
My head gasket is leaking — will Forte Radiator Stop Leak fix it?
Only for very minor, early-stage head gasket weeps — where coolant loss is slight, there is no white smoke, no coolant in the oil and no overheating. A head gasket leak showing any of these symptoms is a serious mechanical failure that requires professional repair. Forte Radiator Stop Leak is not a substitute for head gasket replacement in those cases.
Can I use it as a preventative treatment?
Yes. Added to a fresh antifreeze change, Forte Radiator Stop Leak also functions as a cooling system conditioner — neutralising acids and providing additional corrosion protection throughout the entire system. This can help prevent minor leaks developing in an ageing cooling system.
Should I use it before or after changing my antifreeze?
After — and flush first. The correct sequence is: flush with
Forte Bio Degreaser & Cooling System Flush, drain, refill with fresh antifreeze, then add Forte Radiator Stop Leak to the fresh antifreeze. A clean system gives the sealing chemistry the best possible environment to work in.
