Yanmar engine oil vs generic

[Allan S]

When I was a marine engineer, we fell for all the hyp about oil additives and synthetic oil too. then I got educated by a chemical engineer at a refinery. Change your oil regulary, even use refurbished oil, the cheapest will do. The additive break down soon enough and if you started with, lets say, a 5W40 oil you'll just end up the the W40 in a short time. He said, and follows his own advise and puts the oil rated for whatever temperature he will be operating in and saves a bundle. I have followed his lead for some time now. Just don't mix the brands of oil.....Allan

[Khagan1227]

Originally Posted by Allan S

When I was a marine engineer, we fell for all the hyp about oil additives and synthetic oil too. then I got educated by a chemical engineer at a refinery. Change your oil regulary, even use refurbished oil, the cheapest will do. The additive break down soon enough and if you started with, lets say, a 5W40 oil you'll just end up the the W40 in a short time. He said, and follows his own advise and puts the oil rated for whatever temperature he will be operating in and saves a bundle. I have followed his lead for some time now. Just don't mix the brands of oil.....Allan

Ummm no. The "W" stands for winter, or tells the consumer, this is a multi-viscosity oil., the 5 (or 0, 20, 30) preceeding the W is a realitive number that tells how easily the engine will turn over in cold temperatures, using a cold crank simulator. The 40 is the weight of the oil at 100 degree C, it will have the same viscosity charateristics as SAE 40 oil. This oil can be used over a much greater temperature range than SAE 40 weight oil, which is called a mono-grade oil, since it is for use in constant temperature applications. As such a mono-grade oil usually has a low VI (viscosity index) number, which means the oil thickens very quickly as the temperature gets colder. Since these are CHARATERISTICS of the oil, this does NOT change (much) over the life of the oil. 5W40 oil does NOT become SAE 40.

The viscosity of oil has nothing to do with being Synthetic or Mineral. 5W30 syn and 5W30 Mineral oil have the same viscosity properties at 100 degrees C. An 0W-30 synthetic oil is capable of pumping easily at -62 degrees F and flowing at even lower temperatures. Conventional oils are essentially frozen solid at that temperature, so there's simply no conventional equivalent to this new grade. There are 5W-30 conventional and synthetic oils, but even here, the synthetic has a real-world advantage: Mobil 1's 5W-30 will pump at -58-degrees F, compared to about -35-degrees F for a conventional oil.

Perhaps I need to be more clear, but when I say additives, I am NOT talking about Slick 50, etc, I am talking about additives such as ZDDP, detergents and dispersants to help keep the engine clean by minimizing sludge buildup, corrosion inhibitors, and alkaline additives to neutralize acidic oxidation products of the oil.

I don't know your friend the Chemical Engineer, but I hope his abilities as a CE are better than his knowledge of oil.

[Allan S]

Khagan, you just repeated what I said abiet in a more formal format, Kudos on the tossed in isult to my friend.

[zeta]

oil thread = pissing match

[Allan S]

Yeah, I give the win to him...lol

[djmarchand]

How can such a simple question generate 33 (now 34) answers. It was fully answered in the first two replies. Of course probably 30 of the replies were of the nature "my thing is better than your thing" or "I know better than the guy who just posted before me" or some such stuff.

[Dulcesuenos]

Originally Posted by sabray

fan of amsoil. my oil though still changed at near 100 hours use is much cleaner. near the way it was when i put it in. impressed with the noticable difference.

Not meaning to offend anyone but I love statements like these, your oil is coming out clean because Amsoil's dont have a very good dispersant or detergent package. If your oil is coming out clean it is probably leaving deposits in the engine. Not good.
Dispersants break down the "sludgey" thicker deposits, that are always forming in almost any internal combustion motor, and they are definitly forming in a diesel motor.
Synthetics for the most part clean much better and actualy target piston deposits that most conventionals can't effect. Also oils used in marine environments tend to have a higher concentration of corrosion inhibitors, which many "Truck, or Automotive" oils do not or at least in much lower concentration. As for PAO's some synthetics are made from them some are not, Amsoil, and Mobil are using PAO's (made from Paraffin base stocks), while many other companies are making "synthetics from mineral / dino oil, which are much much more compatible with engine seals, and plastic internal engine parts. PAO based synthetics tend to shrink seals, and therefore need a higher concentration of esters to fight that. I used mobil long ago but at 110k the engine developed leaks all over, not happy.

[Dragon Lady]

What makes me laugh is the OP asked if he could save money by using a good quality generic oil instead of the more expensive factory brand.
What we have ended up with is a whole load of crankers telling us what experts they are and how he should be using a more expensive oil that is designed for F1 cars and MotoGP bikes.

[lockie]

OP is now very confused. Wondering if Yanmar's price, although extortionate, might still be cheaper than the therapist's couch.

[Khagan1227]

In a nutshell, as long as the oil you are using meets the manufactures minimum requirements (like the SF rating in automotive motor oil) you will maintain your warranty and the donk will perform as well as someone else's who is using the Yanmar brand oil.

[atoll]

any body had oil break down and come pissing out the breather on the valve cover,we had this after using some cheap indian oil coming up the red sea after about 250 hours of motoring?

fortunately i noticed we had no oil pressure and shut the engine down but hell was the engine room a mess,oil everywhere