OIL PLUG 825490

Function and technical context

The 825490 oil cap is the airtight seal for the lubricant reservoir on Mercury, Mariner, Mercruiser, Parsun and Yamaha marine engines. Its function is to maintain the integrity of the oil circuit, avoiding leaks during engine operation and preventing the entry of water, contaminants and dirt into the lubrication system. A defective seal can cause significant oil losses, a decrease in lubricant viscosity, increased friction between internal components and, in extreme cases, engine seizure due to lack of lubrication. Therefore, its condition is decisive for the durability of the engine block and the moving parts of the boat.

When to replace this part?

The most common symptoms of failure of this plug include oil stains in the engine space, visible loss of lubricant level without apparent cause, and the smell of burning oil during navigation. It is recommended to inspect and clean the plug at each seasonal oil change, and replace it if it presents cracks, deformations or loss of closing capacity. The preventive replacement of this component is an economical practice that avoids costly repairs due to contamination of the lubricant circuit or damage to the engine during navigation.

Engine Compatibility

Mercury/MerCruiser

Equivalent manufacturer part numbers