Synthetic Oil

[tjr818]

We are having a debate at our harbor about the use of synthetic oil in older engines. Is it safe to use, okay to use, or better to use synthetic oil in older diesel engines?

[Jim Walsh]

We are having a debate at our harbor about the use of synthetic oil in older engines. Is it safe to use, okay to use, or better to use synthetic oil in older diesel engines?

I don't use synthetic oil in my 2007 Universal M-25XPB but I just checked the manual and they don't specify dino or synthetic oil, only that it meets certain AP specifications.
That being said, I would be on the side of those who say "okay to use" in your debate, based on the AP specifications meeting the grade required by the manufacturer of the powerplant. "Better to use" would be like debating politics or religion

[bottomscraper]

From what I understand the Universal M25 is Kubota based.

I can tell you that Beta (Kubota based) specifically says
"Do not use lubricant additives, and we do not recommended totally synthetic oil."

And Kubota themselves say:

Q: Can I use synthetic oil in my Kubota engine?

A: Kubota recommends oil with an API rating of CF or higher. If the synthetic oil meets those standards, it can be used in Kubota engines.

You may take that with however many grains of salt that you wish.

[mgphl52]

Unless the engine is torn down, thoroughly cleaned and reassembled with synthetic oil,
I do not see any benefit in switching. JMHO...

[John Stone]

I don't have a diesel engine. But I run full synthetic in both our automobiles. When it comes to gas engines, based on everything I have read and all the people I have talked to, synthetic is a better oil. The reason is it does not break down as quickly and holds up better in high heat. I think most race cars are running synthetic these days.

But, (isn't there always a but) I think the real advantage is it last longer. So, instead of changing oil at 4000 miles we change at 8000 miles. And since I change all our oil it means I do it less often which provides me more time for the Far Reach.

I think the way to look at this might be if the oil meets the specifications for your engine, then use it IF you will change the oil less often providing you some tangible benefit. If you are going to change oil at the same interval I don't see the value in going to synthetic. Another thing to consider is if you are going to go longer between oil changes then you need a filter that can go longer as well.

One more thing--if you switch to synthetic you are not supposed to switch back. Synthetic is not easy to get everywhere so that might be a consideration as well.

[Maine_Buzzard]

For an engine that might see 50-100 hours a season, the longevity of synthetic is getting poured into the recycling barrel.

I will agree that discussions of service procedures and religion are highly similar and should be proceeded by "My personal and unique preference is..."

[jbenagh]

I'm mostly with John: all my wheeled vehicles use synthetic 5W30 as does Christine C's MD7A. Mostly so I can safely do one change per year in the street cars. One type of oil means a lot fewer jugs and bottles in the garage which I think saves me money overall. And, CC starts much better in cold weather (under 60F) with Synthetic Mobil 1 than the Rotella I used the first 2 seasons. A big complaint about synthetics is extra leakage but I have not noticed any significant change. I have switched to the "high mileage formula" since my 1994 Miata has 185,000 miles, the VW has 165,000 miles and the 1982 MD7A is of unknown engine hours since the meter was broken when I bought her in 2010 but I have added about 500 hours since then.

Jeff

PS I think my Mobil 1 vs. Rotella might cost me $10/yr. If so this is possibly the smallest boat expense I have ever worried about except maybe replacing the salt and pepper shakers vs. cleaning them and restocking them