SCREW 822625

Function and technical context

The M20 nipple screw 822625 is a fixing and sealing element that operates in the cooling circuit ducts of Mercury, Mariner and Mercruiser engines. This part ensures the hermetic retention of the water chambers and flexible ducts, preventing coolant leaks during engine operation in variable navigation conditions. Its function is critical in the cooling system: any deterioration in the fastening allows the entry of salt water or loss of coolant, triggering engine overheating and irreversible internal damage to cylinders and gaskets.

When to replace this part?

The retaining nipple bolts on marine cooling systems should be checked annually before each sailing campaign, especially if the engine has been idle for months. Salt corrosion and continuous engine vibration progressively degrade the sealing capacity of these elements, manifesting in coolant leaks around the ducts or the formation of mineral deposits in the joints. Replacing this screw preventatively during seasonal maintenance prevents emergencies at sea and significantly prolongs the life of the entire cooling system.

Mercury/MerCruiser

Equivalent manufacturer part numbers