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For Over 80 Years, Radiator Specialty Company products help make things work better.                              

GUNKŪ offers engine oil additives and motor flushes to treat symptoms and improve performance... including:
Engine Oil Additives
Stop Smokin' Oil Treatment
helps free sticking rings and reduces smoke from 'blow-by'. Add between or at oil changes.
Motor MedicŪ Oil Treatment
with Sludge Guard keeps engines cleaner. Cuts friction and engine wear. Helps reduce smoke and oil burning. Use at oil change.
Motor Flush
removes gum and sludge, frees sticking valve lifters, & piston rings in 5 minutes.
Synthetic Motor Flush
is perfect for turbocharged diesel and gasoline engines. It removes gum and sludge, frees sticking valve lifters, & piston rings.
Engine Oil Stop Leak
conditions seals and gaskets to reduce oil leaks. Great for aging engines.
BROWSE ALL ENGINE OIL ADDITIVES
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