Originally Posted By: PDX2500HD
10,000 miles, on a truck that might drive 5000 a year IS an extended interval as far as I'm concerned. I plan to use 6 months because I'm being conservative, but if I went 2 years, I'd have to use synthetic, wouldn't you agree? There are shelf life issues to any natural product, and many synthetic products.. I am sure I take more risk using a mineral based oil than a synthetic oil over a two year period. Sure, going by your experience and word that might not be true, but I've heard equally passionate pontification by proponents of synthetics. I don't disagree that the primary advantage to synthetic oil is extended interval, but I do disagree that this doesn't "make it better".. it does mean it's more stable.. period.
Here is just one article I found with google which backs this up, and I can find dozens of others, but why? I've made up my mind... Synthetic is all that goes in anything I own.... except my Honda mower which might get 10 hours of use a year and gets an oil change annually.
Article:
http://www.machinerylubrication.com/Read/660/changing-oil-synthetic
Also, I have on 4 occasions started my truck at a OAT of in the
No, 6 months and 5k miles is NOT an extended OCI, not to the Dmax engine, not to the OEM, not to the lubricant, and not to the industry. It means, by your own admission, extended to you. The OEM (GM) states that you may follow the OLM and OCI up to one year. Typically, guys are seeing 8k to 11k miles on the OLM under conditions you state (infrequent moderate towing and such). The OLM from GM is based upon the use of any qualified product; that includes (and is predicated on) conventional oils being the "norm".
Do lubes have a shelf life? Yes. But they go WAY past 1 year on chronological age! New in the bottle, most people consider 5 years as safe. Once put into the crank case, you can still get up to four years in some circumstances. There are some used oil analysis here (both conventional and synthetic) that show two and three years is perfectly safe, situation dependent. Jim Allen, for one, does some longer OCIs well past one year, and there are no concerns in his approach and he has used oil analysis data as proof. I do three years with conventional HDEO in my 1966 Mustang; no worries. Armagedon will not set in once the oil passes 6 months, or even 1 year. The oil has ZERO idea of how old it is. Only a used oil analysis can tell you if an oil is no longer fit for service, not the calendar. Now, there is some caveot to this type of OCI. You equipment must be in good mechanical working order; no external/internal leaks that would introduce contaminants. You must have drive cycles that contribute to getting the moisture out. Etc. A brand new LML should have no issues here, presumably.
Here are some links to used oil analysis as proof of concept for blowing well past the "or one year" mentality:
https://bobistheoilguy.com/forums/threads/31-month-331-hour-uoa.134754/
https://bobistheoilguy.com/forums/threads/wm-super-tech-15w40-a-year-in-my-cummins.131535/
http://www.bobistheoilguy.com/forums/ubb...rue#Post2082252
And, GM's official statement is that the "preferred" grade is 15w40 down to zero degrees, so the temps you see (
We have many members here that operate vehicles far longer than I ever will, because of their type of use. One member here, ottomatic, got over 450k miles on his 6.9IDI before it was stolen. He has almost 350k miles on his 7.3PSD. All on conventional oil; not a drop of synthetic in sight. Garak operates his fleet well past what normal folks will ever see, most all on conventional oil AFAIK. Here's a couple examples I'm fond of:
http://www.knfilters.com/news/news.aspx?id=157
http://www.autoblog.com/2008/02/01/wisconsin-mans-91-silverado-set-to-hit-1-million-miles/
Now, this isn't "normal" mileage for most vehicles; these guys clearly put on miles at an accelerated rate. But the point to take away from this is that conventional oils took them all the way there; not a drop of synthetic in sight. The lube base stock didn't get them there; GOOD MAINTENANCE PRACTICES DID!
Here's the giant misconception you're under, in a nutshell. You seem to believe that synthetics will make the engine last longer or protect it "better"; for "normal" circumstances, nothing could be further from the truth. Synthetics (and bypass filtration) make the FLUIDS last longer in service. The enemy of the internal combustion engine is contamination, in many forms. You have two ways to get rid of that contamination; flush it out or filter it out. Either way works. They are two roads to the same end. Synthetics do not make equipment last longer. Proper maintenance plans are what make equipment last a long time. Conventional oils are perfectly capable of protecting your investment with every bit the capability of synthethics; proven in too many used oil analysis and real life examples to debate that. What conventional's cannot do is extend their OCI to the level of the synthetics.
Synthetics are fantastic products; I use them in some specific circumstances. But I don't use them without understanding both their benefits and limitations. They are NOT a one size fits all answer for everything. They are surrounded with hype and rhetoric; that's a shame, because in my opinion it tarnishes their true abilities. I do not credit synthetics with the extension of equipment life cycle. I do credit them with extended OCI abilities. Do NOT confuse lubricant life cycle with equipment life cycle; they are not the same concept.
In your Dmax, under your driving conditions, you'll not see one minute little differnce in the "advantage" of synthetics, given the type serivce and maintenance you plan. But don't take my word for it. Why not run a little experiment for yourself. Purchase some synthetics, run some used oil analysis, then compare your 6 month (low mileage) wear metals to my annual conventional 10w30 runs. Or, compare your results to the excellent conventional 15w40 Delo, Delvac, Rotella runs from other members with Dmax engines. Don't let me convince you; convince yourself.
