Determine Whether to Utilize Older CI-4 Rated Diesel Oil Instead of the Newer CJ-4?
Jul 1, 2009 More Saving
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It is common to hear individuals talking about the relative positives & negatives of the CJ-4 vs. the older CI-4 diesel engine oils. So, it seems worthwhile to layout the relative similarities and differences between using diesel oils that meet each of these respective API classifications.
Many of our customers are seeking our 15w40 viscosity AMSOIL synthetic diesel engine oil. Most often, this is either because they have some misgivings with regard to switching over to a “lower” viscosity oil or because they’ve been told “bad things” about the new CJ-4 oils.
Key Additives Reduced in CJ-4 Oils
It is important to note, our AME 15w40 synthetic diesel motor oil does NOT meet API CJ-4 specs because in order to meet CJ-4 classification requirements motor oil blenders/manufacturers had to make significant reductions in the levels of key additives in acid fighting. That means that the TBN was lowered.
Are Oil Drain Intervals Shortened?
As a result, it is assumed that the long oil change abilities of API CJ-4 oils should be much less as compared to the older CI-4 oils with higher TBN values in order to blend a diesel engine oil that is more likely compatible with Exhaust Gas Recirculation systems found on 2007 and newer diesel vehicles.
Current EGR systems are putting HEAVY soot load on the lubricant in the crankcase. This increased soot load requires an increase in detergents and dispersants in these new API CJ-4 oils - keeping things clean is always a good thing.
Also true is that, lower-tier CI-4 diesel oils (petroleum and “pseudo-synthetic” based) have been forced to implement upgrades to their basestock quality in order to meet CJ-4 classification specs. Hence, the CJ-4 oils are, as relates to the basestocks used, a more advanced diesel engine oil. In contrast, if you are making comparisons between premium SYNTHETIC CJ-4 rated oils, the base oils are likely pretty similar to their CI-4 precursors since the original basestocks used for the CI-4 rated oils were likely already plenty capable of meeting CJ-4 requirements.
As evidenced in the previous paragraphs, there have actually been numerous improvements made in converting from CI-4 to CJ-4 rated oils. n fact, the only drawback I can really see to moving from a CI-4 rated oil to a CJ-4 rated oil IS the potentially shorter drain intervals due to the lower TBN of such oils. However, if you don’t take your vehicles to the limit of your oil anyway, then you won’t likely notice the difference.
It is actually quite common for diesel owners to drain their oil long before it is necessary. In most cases, this is simply because they fear that longer drain intervals will not effectively protect their expensive engines. So, even though the CI-4 15w40 oil MIGHT offer a longer drain than our CJ-4 5w40, it’s likely that most end users will not notice because they never take their oil to the limit anyway.
In addition, there seems to be evidence that, although the starting TBN value of the CJ-4 oils is lower than CI-4 oils, TBN “retention” seems better with the CJ-4 oils. If these initial oil analysis results are proven true by continued field testing, we MAY find that CJ-4 oils are able to offer oil drain intervals similar to higher TBN CI-4 oils.
The end result: If you don’t intend on trying to extend your oil drain intervals beyond what is typical, and even if you do, you may not be at all affected by the lowering of the TBN values for CJ-4 oils. Even better, increases and improvements in the additives related to wear protection and detergency of a CJ-4 oil will be of benefit to you. Hence, for many companies and individuals owning diesel engines, the CJ-4 rated oil COULD actually prove to be the best option, whether you have a newer model diesel or not.
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Tags: auto maintenance, auto repair, Diesel Engine Oil, diesel motor oil, Diesel Oil, Diesels, Engine Oil, engines, More Saving, Motor Oil, Oil Changes, trucking, trucks, vehicle maintenance, vehicle repair
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