Question as I consider next oil change....

Our 1984 E30+ has a 16 hp Universal diesel engine (model 5416) with 2,242 engine hours. For the past 11 years I have used HD SAE 30 engine oil, which is what the original manual recommended, with HD10-40 recommended as a back-up if that isn't available. Our local outlet is no longer carrying the HD SAE30 oil, so I need to make a change. There is a semi-synthetic SAE 15-40 available at slightly higher cost or regular 15-40. I normally change the oil and filter about every 75 engine hours, two to three times per year on average.

In his book Nigel Calder suggests that there is little to be gained by using synthetic oil in sailboat diesel engines, but both the original manual and his book are now quite dated and engine oils have evolved over time. So my question is, are any of you switching to semi-synthetic or synthetic oil and what grade are you using to get the best value for dollar in keeping our engines running well.

In my case I sail year round, with temps on Vancouver Island dipping to between 0 and 5 degrees Celsius (about 32 to 40 degrees Fahrenheit) in winter, so what would be best for starting the engine and long term engine wear year-round?

Thanks for any feedback or advice!

Frank

How about a different "local outlet"? I find it hard to believe there are no Canadian Tyre or Walmarts on Vancouver Island.

Yeah, it was Canadian Tire that carried the five litre jug of HD SAE 30, but no longer seen to do so, replacing it with the semi synthetic 15-40. Walmart and other outlets have never carried the SAE 30 here. I haven't tried the Kubota tractor dealers yet, but might try that.
Frank

Synthetic Oil

Hi Frank
Our Mobil 1 5w-40 Truck experiences have been all good for too many years to recall.
1. We use so few quarts per change (2.25) that price is no object
2. The synthetic cleans up very nicely
3. The synthetic is still slippery when pumped out. Pumps easier too.
4. Low pressure beeper used to beep 2-3 second on conventional oil. Now beeps only once or twice.
Sorry nothing profound here but I like the synthetic a lot.
Best Regards
Paat

Not synthetic

Frank, while I wouldn't hesitate to switch a modern vehicle to synthetic, a 33 year old diesel is another matter.

Seals would be my biggest concern. Your engine has got sludge and carbon deposits that you definitely don't want to disturb. Some semi synthetic oils are high detergent and that is totally unnecessary for your motor. Unintended consequences could result.

Try and find your straight 30 weight but failing that use Delo or Rotella 15W-40 multigrade.

Good luck

Rob

How often have you changed your oil ?? , I have used synthetic oil since new changing every year or 100 hours with great results, If your engine is clean try it , I use W15-40, I will be easier to start in cold weather and it is much better not absorbing moisture. If you feel like its got some sludge in the motor leave well enough alone and find the oil you have used from another source. Try NAPA