CJ-4 Diesel Oils only for 2007 & later models – they’re NOT for earlier diesels!
DO NOT use CJ-4 oil in vehicles prior to 2007 models, unless you want increased wear and more frequent oil changes: because the 2006 and earlier models do not have diesel particulate filters (DPF’s), they do not need the restricted formulation of these CJ-4 oils.
Amsoil’s new DEO oil is a premium 5W-40 synthetic diesel engine oil that is certainly among the best examples of the new CJ-4 emissions-spec oils. In fact, it’s one of the only examples: most oil companies still don’t have a CJ-4 diesel engine oil formulation, much less have it available in the U.S. market as of October 2006. Even more kudos to Amsoil, because their CJ-4 oil performance is still better than most CI-4+ oils, and because it’s proven – it has already logged over 12 million fleet miles.
To be fair, this article title isn’t completely true: if you’re changing your fleet over to Amsoil and take it all to CJ-4 so that you can be certain of always using a DPF-compatible oil, you are still getting a better performing oil across your entire fleet than your current petroleum CI-4+ oil. So don’t take me wrong.
But while this CJ-4 oil is the best that Amsoil can formulate within the specification requirements, and it is the best performer available in this group, the CJ-4 spec does compromise oil performance with brand-new limitations on the oil additive contents. This is why Amsoil only recommends DEO “for use according to the longest service interval established by the engine, vehicle or equipment manufacturer”: there is concern that the additive package cannot handle the dramatically extended (25,000+ mile) drain intervals with the conservative safety margins that Amsoil’s other diesel oils are designed for. Oil sampling analysis will be a more essential element than ever before in fleet management for 2007+ diesels.
So in 2006 and earlier model diesels, always use the 15W-40 (AME) or the high-fuel-efficiency 5W-30 (HDD) if your goal is to maximize fuel economy and engine life while minimizing your maintenance costs. Amsoil will NOT be discontinuing these CI-4+ oils anytime in the foreseeable future.
Which oil should you use for 2006 and earlier diesel models?
The two best choices on the market – per the published technical performance test data, field fleet testing, and product warranty – are the Amsoil 15W-40 Premium Heavy Duty Diesel & Marine oil (product code AME), or the Amsoil Series 3000 5W-30 Heavy Duty Diesel Motor Oil (product HDD). Despite your owner’s manual recommendation of a 15W-40 oil, your PowerStroke/Duramax/Cummins/Volvo/Caterpillar engine – like nearly all engines – is designed to use a 30-weight oil. The 15W-40 recommendation is not based on engine design, but on the assumption that 40-weight petroleum oils will often “shear back” to a 30-weight oil in diesels, and if you use a 30-weight oil that shears back to a 20-weight oil you will have wear problems (or worse). Of course, AMSOIL’s full PAO synthetic HDD formulation will maintain viscosity as long as you are using it as recommended in a healthy engine (no fuel getting in the oil, for example) – so your engine will enjoy year-round benefit from the 30-weight oil it was designed for.
Both oils are 25,000 mile oils that outperform every other available diesel oil on the market, and are LESS EXPENSIVE to use because of those extended drain intervals. Both oils are also superb performers in gasoline engines. Either oil will work well for you, but my best recommendation is for you to make an informed choice based on your specific needs. Here are some suggestions to help you:
For this Application… Pick this oil:
Fuel Economy Series 3000 5W-30 (HDD)
Cold Temperature Performance Series 3000 5W-30 (HDD)
All-fleet oil for home/farm/garden Series 3000 5W-30 (HDD)
Lowest oil usage 15W-40 (AME)
OTR Freight Hauling 5W-30 (HDD) – or 15W-40 (AME)*
All-fleet oil for class 3-8 15W-40 (AME) – or 5W-30 (HDD)*
All-purpose oil for logging/heavy-construction 15W-40 (AME)*
*While it is difficult to compare them, Engineers generally agree the thicker 15W-40 (AME) will provide slightly more wear protection than 5W-30 (HDD) in extremely heavy applications, particularly off-road/gravel/rock-crawling applications where drivetrains are subject to heavy torsional shock-loading. However, for highway/city mileage, HDD fuel economy savings probably exceed savings from reduced wear with AME – if there is any reduced wear at all with AME in highway/city driving.