0w-40 in a Duramax

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May 9, 2004
Looking for opinions on using a 0w-40 diesel oil in a 2011 duramax. I have an endless supply of Petro Canada Duron E 0w-40 oil and wondering if there would be any issues in using it. You read so much about 15w-40 and 5w-40 use in diesels, but people tend to shy away from 0w-40. Is this a engine protection issue or a viscosity shearing down issue????? which means change it sooner. To me I don't see any reason not to use it. The 0W end of it can only be a benefit, although probably not necesary. My plan would be to use it all year round.
Yes you are correct 0w-40 will be better, it gets moving quite a bit faster on start up than the 15w, the 15w-40 as far as "proven" yes it's proven it won't blow up your engine, but that doesn't make it the best choice. We can pretty much all agree most if not nearly all wear occurs on start up, as the crank starts spinning before receiving pressurized oil to lubricate, why would you ever want anything but 0w? Remember the very thickest oil is thinner at operating temp, than the thinnest oil at room temp, the 0w-40 doesn't have as much of a difference between operating temp viscosity and room temp viscosity as the 15w-40. If your really worried it may comfort you to kno, with the recent advances in synthetic oil quality, there's been a growing trend of running 0,5,and 10w-30 oils in diesels calling for a 40, the same way people are starting to drop 20wt oils in cars calling for 30wt(me being one, oil analysis shows its working for my car very well)2-3yrs ago I'd never have even glanced at a 20wt, much less use it, but I've since educated myself thoroughly on oil and added oil analysis to my regular maintenance(can't beat $35 to kno for sure just how good your oil and filter combo is working and tell you if you went too long or could have gone longer.) -srv
If the oil meets the necessary certifications is see no issues with using it. We all know the benefits of using a 0w in colder conditions. I doubt there is much benefit in warmer temps though. Co-op has a diesel 0w-40 that is rated for like -73c and is certified for use in modern diesels. I'm currently using it in my air compressors at work. Gonna try it mixed 50/50 with tgmo. It's co-op badged but Mobil made.
The Dirtymax engines seem to not care one whit about what lubricant is used in them. If you've got an 'endless supply' of PC Duron E 0w40 I would use it all year long with confidence.
Since the Duron E 0w40 is a fully synthetic oil meeting CJ-4, it sounds like the perfect fit for both your climate and your budget.
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An "endless supply"? Gosh - perhaps you could share? I see no issue with using 0w-40 for the OEM OCI via the OLM. If you are going to greatly extend, then certainly a UOA is a necessity. I will note that oil pressure is not the only thing that controls wear. In fact, it is the tribochemical barrier of oxidized oil and additives that most greatly reduces wear; proven in SAE studies. Therefore, the several seconds difference of pressure building up between a 0w-40 and a 15w-40 probalby does not manifest into the wear delta folks think it does. And macro UOA data shows this to be true as well. If you can get it cheap or free, then by all means use it! The Dmax really does not care what you use as long as it's a CH-4 or better for older units, or CJ-4 for the "regen" models.
Well thanks everyone, I will definately try this oil for a couple of OCI's. I may even do a analysis to see how things turn out.
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