I believe it is of the same color as land engine oil
Shell Melina S30 marine engine oil color
Mixing oil weights is a NO,NO.
The marine main engine lube oil sump is critical to keep the engine running. If the pump gets clogged or fails, then the engine will seize and be ruined.
You must use a special marine oil of 10-40 W or 5-40 W. Normal car and land engine oil does not displace water. Marine oils can be purchased from many large engine oil producers, and there are also companies that specialize in marine oils.
It depends on the fluid. Antifreeze is a different color from engine oil.
Blown head gasket or cracked head.
When engine oil turns gray or milkey cream color, its a sign of moisture in the oil.
Most likely head gaskets or cracked water jacket.
the oil
not unless there is a significant color change in the oil, might be because of when the oil leaving the engine air is hitting it called aeration
are you sure you are looking at engine oil or is it the tranny fluid(which is reddish brown but there are also synthetic motor oil that are reddish in color but DO NOT MIX regular oil w/synthetic oil make sure of what you have before adding causes major engine problems
find oil filter to suit a beta marine diesel engine model BD722. please cross reference. the betapart no. is 211-63760