By: Tony Athens / Seaboard Marine / August 2008 

Since understanding oil pan capacities & their relationship to "dip sticks" seems to be an ongoing topic of discussion, I will attempt to explain what it really means.

What is most important to remember or understand is that oil pan (sump) capacity is exactly that, and HAS ZERO to do with oil filters, oil lines, oil coolers or ?? The second most important part of understanding oil capacity is to realize that the dipstick measures OIL PAN capacity and it has NOTHING to do with the oil filter being full or not, and/or any other oil in the system which is part of the "total system capacity". "System Capacity" is that amount of oil in the pan (the dipstick measures that), and all of the other oil that is in the engine (oil filter, lines & hoses, oil galleries, etc.) that cannot be drained from the oil pan under normal circumstances.

Below is a picture of a Cummins 330/370 Diamond with late style reversible screw-in locking dip stick. Cummins changed the marine oil pan design for this engine about 2002 (maybe the 4th time now since 1985 when they released the Marine version of the 5.9 B series) to include better internal baffling (helps to mitigates "oil windage"), and came up with a new designed reversible and locking dip stick - Nice

Below is a picture of correctly, and incorrectly, marked dip sticks. The upper scallop notches were done by a "Cummins Tech" who had no clue. Not only did he add 2-3 gallon too much oil when he marked them, the notch he put would surely cause the dip sticks to eventually fatigue and fail. The lower X's show the CORRECT OIL LEVEL, and done per the book using some common sense. These are from a QSM that has seen more than its share of dip stick issues over the years. Somehow, I always thought the dip stick was a simple part of the overall engine design ????

And last, running your engine on the low mark has NO detrimental effects on the engine, and in the case of a B series Cummins that uses the very shallow marine oil pan, this is a recommended practice from us to help alleviate or keep oil "whipping" to a minimum.. In general, and from a personal point of view, we prefer keeping the oil level in the oil pan in-between the "marks" on a correctly marked dip stick on all engines regardless of the color. This also applies to transmissions and/or gear boxes.

Listed below are the factory oil capacity numbers for the popular Cummins marine engines.

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