Re: Which oil is king? -ALL BRAND NAMES!
TresCrows:
Answer to question 1:
Detroit Diesel, hereinafter referred to as DDEC, recommends 1200 Delvac 15-40 to all their purchasers. In fact, there is a label stating just that on the valve cover. I have a '98 Western Star with a 3406-E model 550 hp. Caterpillar recommends Shell Roptella T. Shell has reformulated their Rotella T and added various additives that will extend the service life of the oil in extreme applications, hence "XLA" (Answer to question 2). If a DDEC or Cat engine has a failure due to lube oil breakdown, I would imagine that there were would be a warranty problem. A couple of thing that the non-trucking public isn't aware of is 1. That the change interval for lube oil in class 8 diesels is normally 12,000miles. because of the extreme operating temperatures produced by commercial diesels ( the temperature of piston crowns can exceed 1,000 degrees) and the fact that class 8 diesels have provisions for oiling of the underside of the piston crowns subjects the oil to high temperature. 2. The emmission standards set forth by the Federal Government has caused DDEC and cat to redisign their engines to meet those standards. The redesign has resulted in increased internal temperature also. That high temperature along with extended drain intervals cause oxidation in the lube oil and a loss of the additive package.
Delvac and Rotella are not true petroleum based oils. They are hybrids. Their base stocks are naturally produced oils but they have synthetic oils added to them to increase their resistance to breakdown. The also have additive packages to increase their lubricity and antifoaming along with other additives to prolong their operating life.
As far as damage to a diesel engine. Like I stated before, if lubrication was an issue on a warranty matter, I have a feeling that the engine manufacturer would not warrant the engine. I don't think it would matter what oil you'd used.
I always use the recommended oil as to API grade or brand if specified. All engine manufacturers do exhaustive testing to determine what grad or API certification is best for their engine. In the case of DDEC, their recommendation of a specific brand for their engines, I would be reasonably sure that that recommendation also came from exhaustive testing. Even though I have a Caterpillar engine, I am aware that DDEC is very concerned about quality and the longevity of their engines.
As far as lubrication failure in a Class 8 engine, In 32 years of trucking, I have never seen an engine failure due directly to the failure of lube oil. I have seen engines destroyed by oil failure due to dilution from antifreeze or diesel fuel. Cat's are know for dropping the injector cups which allow diesel fuel to mix with the oil and older Cats had a habit of perforating the head gasket on number 6 which allowed antifreeze to mix with the oil, but direct failure due to lube oil, I've never seen one.
I am not saying that Amsoil or any other high priced synthetic oil is no good, on the contrary actually. The COST of the oil makes it prohibitive. Oil changes and filter changes recommended by the manufacturer are the best insurance for engine longevity.
I actually use Amsoil myself. I use Amsoil Synthetic 2 stroke oil in my Arctic Cats. It has a very low ash content, low pour point and never fouls plugs. It's also very expensive and I only use about 2 gallons a year. Most all 2 stroke oils are synthetic, I seem to have the best Luck with Amsoil in this application.
Now I am going to heat thing up.....
Oils are basically classified as 2 types, parraffin based oils and petroleum based oils. Synthetic additives are added to both types to enhance their qualities. Quaker State, Wolfs Head, Valvoline and others are parraffin based oils whereas Rotella, Delvac, Castrol and others are petroleum based oils.
A parraffin based oil will congeal inside an engine at high temperatures. Actually the paraffin seperates and coats the inside of the engine, especially if the oil changes are infrequent. That's why, in an older engine that has had a steady diet of say Quaker State, you take off a valve cover and you can't see the rocker arms anymore. All you see is a bunch of goo. Petroleum based oils on the other hand have no paraffin to seperate so you get no goo. The only good thing about the goo is if you lose your oil pressure, you won't spin a bearing or wip a cam. The goo lubricates everything.
I hope that answers your questions and probably adds more questions too!!
I am familiar with the study you are looking for. It was done by API for ASTM standards.
