Minimum hrs before oil change?

Tomco

Tomco

Active Member
Aug 16, 2012
455
Ottawa, Ontario
Boat Info
2004 420 Sedan Bridge
GHS Hydraulic Lift
11' Walker Bay, 30hp
Engines
Cummins 6CTA 8.3M
From a recent conversation with a dock member regarding winterization they were not planning on changing their (diesel) oil because they had not put many hours on the boat this season. The PO of our new boat did the same last season before I purchased … so it is not uncommon thinking, although I haven't had one of these seasons!

Got to wondering how common this is and if you would consider not changing your oil annually if you had a 'low-hr' season? what would be the number of hrs at which you would make this call? does it matter if it is gas or diesel engine?
 
I don't know about the number of hours recommended, but I change mine every other year because of the low hours I put on it.

Just finished my 10th season with this boat and I have about 425 hours.
 
IMG_4230.JPG
I generally change the oil regardless of hours. Although one year we put just 10 hours on the boat due to work issues. Did not change the oil on the advice of my service tech who I trust. No harm that I could notice.
 
I change every 100 hours, but we also boat year round and don't winterize.
 
My Merc manual says 100hrs or annually, I generally run 40-60hrs a year and just change it regardless of hours at the end of the year. If for some reason I only ran say 10hrs one year, I probably would still change it (unless the reason I only ran 10hrs was keeping me from changing it!). The whole reason for changing oil at end of year is so dirty oil doesn't sit in the engine during layup - not sure how much that matters on a 4-5month layup. I change mine at the end of the year out of convenience - so things are ready to go in the spring. My old Correct Craft I always changed it in the spring - still running strong at 2000hrs when I sold it. I am talking about a gasoline engine that is pretty inexpensive to change the oil. The OP has diesels, different animal, much larger oil capacity, longer oil change intervals and a lot more expensive to change the oil. I didn't think most diesel owners adhere to the end of the season rule. But I have never owned a diesel.
 
If you’ve put more than say 50 on it and are planning to lay it up this winter, then I would change it. Even at 50, the oil is beginning to break down and is developing corrosive characteristics. I personally would not want anything other than fresh oil saturating my blocks for 6 months.
 
Also diesels are much harder on oil than gassers. I would definitely go ahead and change it.
 
I was just changing ours today (350 gassers) and thought to myself I could have just left it. We put 31 hours on this year, and one of them was a repower so I had changed the oil after the first 10 hours - meaning that motor only had 20 hours on the oil.

It looked new, but it's all fresh now. If we have another light use next year I might skip a year. Same with the Genny, I put 4 hours on it. I'm not sure I can justify pulling oil and filter out of it after 4 hours
 
I know a lot of you are firm believers in fall/winter exchange of fluids, but I would like to also point out where is your boat stored over the winter and what type of temperature swings are your motors exposed to? Condensation is a real threat to the engine oil and if you don't have some temp. control over your engines than water in your oil is a real possibility. I guess where I'm going here is that if you can't control temp. swings that produce moisture I might think about waiting until spring to change my oil... Just saying.. Now let me go get some popcorn and a beer... lol
 
I have been operating machinery, from farm equipment on our family prune ranch to high performance aircraft for the last forty years. I've rarely seen actual evidence of engine performance degradation due to oil change intervals. The auto industry has changed oil change intervals from 3000 miles to 10,000 miles on my 2014 BMW 750I. The biggest exposure to engine wear is corrosion due to the accumulation of water in the oil from condensation in the oil separator which drains back to the sump. The real issue is calendar time more than engine hours for recreational vessels anyway. I change my oil annually out of the abundance of caution and its relatively inexpensive insurance since I do it my self. On my 50 Hp diesel front loader tractor that has 300 hrs in 12 years, I've changed the oil twice and haven't given it a second thought. The difference is $60,000 in boat engines verses $10,000 tractor. Prioritieso_O
 
A fellow boater puts a minimum of 600 hours annually on his Cummins 6CTA engines. He got tired of the time and cost changing the oil 6 times a year so he called the Cummins experts at Seaboard Marine and they put him on an oil sampling program to determine when the oil starts to test out as detrimental. The results: He now changes the oil once every two years. That's 1200 hours on the oil. I guess these every year or 100 hours guidelines were put in place by the oil companies to sell oil.
 
Oil analysis is a good idea for changing oil. Cummins says 300 hours or once a year on my 6cta’s. We don’t put anywhere near that on them if we’re not traveling so they get clean oil before going in the barn for 7 months regardless. When we are traveling, at around 200 hrs they start to show metal counts that are higher than what proportional numbers would be at lower hours, so I change it. Nothing drastic, but it’s my boat and I confess to treating it a little differently than the drill rigs and dozers. Every motor is different depending on how it’s used and just “ because”. Similar to oil pressure numbers at various rpms from motor to motor. Your friends motors are easy on oil. We used to have a bunch of 4 BT’s, most of them would be ready for oil changes at 400 to 600 hrs, we had one that we would change at 1000 even though testing said no problems. Kind of like people, they all are little different
 
my3sons said:
Oil analysis is a good idea for changing oil. Cummins says 300 hours or once a year on my 6cta’s. We don’t put anywhere near that on them if we’re not traveling so they get clean oil before going in the barn for 7 months regardless. When we are traveling, at around 200 hrs they start to show metal counts that are higher than what proportional numbers would be at lower hours, so I change it. Nothing drastic, but it’s my boat and I confess to treating it a little differently than the drill rigs and dozers. Every motor is different depending on how it’s used and just “ because”. Similar to oil pressure numbers at various rpms from motor to motor. Your friends motors are easy on oil. We used to have a bunch of 4 BT’s, most of them would be ready for oil changes at 400 to 600 hrs, we had one that we would change at 1000 even though testing said no problems. Kind of like people, they all are little different
Click to expand...
Oil analysis is probably a best way to keep an eye on the condition of the oil. It does get a tad chilly here in the winter and I had thought of the points made regarding condensation in the spring - I prefer to have the engines sit in clean oil over the winter though and this is what our mechanic recommends. I have the oil analysis from last year when we bought the boat to use as a baseline and plan to do it each season to monitor. As Bill stated in his example, good oil sampling can help determine when it is the right time for your engine/situation.

As for interval between changes - it boils down to how much risk are you prepared to take. An oil change cost me $100 (Cdn) per engine for 5gal of oil and a filter … not one of my larger annual cost line items and I feel like I've tucked them in for the winter properly. On the other hand, we have only put approx 15hrs on the generator and I will skip a change this season.
 
You must log in or register to reply here.

Forum statistics

Threads
113,162
Messages
1,427,538
Members
61,069
Latest member
Peter61
Back
Top