Oil Analysis....

[dhays]

I've not done oil analysis before. When I had the boat surveyed oil analysis was part of the that survey. Since then, my engine was replaced with a Cummins Reman. I changed the oil in that engine for the first time a couple weeks ago and took oil samples and sent them off to Blackstone.

My thought was that with a new engine, if I start doing samples now I will be able to spot trouble/trends. While I was at it I had the genset oil tested as well.

Since I've never done it before and since I know nothing about engines of any kind (sad but true) I thought I'd look to TF for some input. Here is the analysis for my Cummins. The oil Cummins used was the Valvoline Premium Blue. What I replaced it with was the Delo 400 LE that I've used in my original engine and genset.

The report seemed generally positive. They recommended going to 180 hours and then checking again. One of the questions I have is Cummins recommends oil change at 250 hours or 3 months. Yeah, I'm not going to change the oil every 3 months and I have been putting about 200 hours on the engine a year. So if I do check the oil at 180 hours and they say go another 100 hours, at what point does the oil simply age out?

 

[Gabe n Em]

We had the same problem last year- we only ran 400 miles (70ish hours). We still changed the oil and filter. I guess it's a habit left over from when we'd winterize a boat, living in new England.....

Sorry, no science to back it up

 

[DavidM]

Your oil report looks good. I would change the oil at Cummins hour intervals but not worry about the three month interval. That is probably for the long distance trucker who put lots of hours on their engines.

I believe that with modern, ultra low sulfur fuels and modern oil additives you don't need to change oil at a calendar interval, not even yearly. Opinions vary however.

David

 

[Ski in NC]

Agree to ignore the calendar oil change interval bit. Good idea to put new oil in if boat is going to be stored over the winter. In my case, boat runs year round and I change at about 300hrs. Sometimes that is under a year, sometimes it is two years.

 

[O C Diver]

I believe that with modern, ultra low sulfur fuels and modern oil additives you don't need to change oil at a calendar interval, not even yearly. Opinions vary however.

David

I don't think marine diesel is ultra low sulphur. Sulphur levels may vary by state, but federal limits aren't the same as over the road vehicles. I agree that changing oil should be on hours not a calendar.

Ted

 

[Larry M]

We change oil on both, hours and calendar. 200 hours or annually, which ever comes first.

I think the sulfur levels are the same for everyone. This came from ValveTechs web site.

http://www.valvtect.com/fileshare/documents/6x8_ultra_low_sulfur_decal.pdf

 

[DavidM]

Non-road diesel: marine, construction and agricultural diesel has been at the same 15 ppm ultra low sulfur sulfur spec as road diesel for the last five years. This is much, much lower than what was the norm before EPA controls.

I believe it was the high sulfur content in past years that resulted in the recommendation to change your oil before winter layup so that corrosive sulfur compounds wouldn't sit there all winter. Today that reason has gone away.

Modern oil also has corrosion inhibitors as well as acid buffers to deal with acid. The TAN value, Total Acid Number, is an indication of acid in the oil. Unfortunately Blackstone doesn't measure this, although it is almost always within spec in today's diesel engines.

Like some old wives tales, this one had a sound basis, but not today. Those old wives tales die hard.

David

 

[dhays]

Thanks guys. Your input is really helpful. On the sailboat Yanmar 4jh4 engine, I changed the oil spring and fall for the most part. With that small engine it was always easy and painless. With the Cummins 5.9L taking 14 quarts, it is a bit more expensive. I have been doing it yearly but would be happy to go to the Cummins recommended 250 hours or when indicated by oil analysis.

 

[AusCan]

Rather than going by a rigid hourly or calendar schedule, I often change mine when preparing for a longish journey.


If the hours are anywhere within 100 hours of the recommended 250 hr interval, I change it rather than having to do it away from the home berth. Setting off with clean oil and filters always makes me feel more confident.

 

[BIG CAT]

At cat. We recommend oil be changed annually if you don't meet the hr interval before then. Every three months seems very early Imo. Being new/reman it will probably take several services for the readings to level off. Then you will have a good baseline for trending. Also oil capacity and hp/load will play into how often the oil should be changed. I have seen applications where they would kill the oil by the 150hr mark but I doubt you are running your stuff anywhere close to that hard.

 

[tiltrider1]

Right or wrong the Black stone is under the impression that you went 130 hours on the oil sample. Based on what they are seeing they believe your oil is good for 180 hours. Since you have changed the type of oil in the engine their estimate has less meaning. If you run for another 130 hours, send in the sample and get back the same results then I would switch to the recommended interval. It never hurts to change oil early but it does waste money.

 

[dhays]

Right or wrong the Black stone is under the impression that you went 130 hours on the oil sample. Based on what they are seeing they believe your oil is good for 180 hours. Since you have changed the type of oil in the engine their estimate has less meaning. If you run for another 130 hours, send in the sample and get back the same results then I would switch to the recommended interval. It never hurts to change oil early but it does waste money.

Yeah, the engine had 131 hours on it when I changed the oil. The engine was new and even though Cummins said that an oil change didn’t need to be done any sooner than the 250 recommended hours, I didn’t feel like waiting that long. Your point about changing the oil is a good one.

 

[FF]

OIL is cheap, even 15 Q of good oil is 1/100 of the sales tax on a replacement engine.

Folks purchase insurance against what "might" happen.

Some of the additives may age,and die , even with out engine hours.

The engine folks understand fairly well what keeps their product for the long term, following their call is simple , and cheap insurance.

WE change oil on hours OR time in the engine , unless the engine was pickled and sealed , another engine mfg procedure in Da Book.