A reader asks: I’ve got a 2019 Ram 2500 with the 6.7L Cummins diesel. My manual says to use 10W-30 motor oil meeting the MS-10902 or API CJ-4 specification. I’m used to running a 5W-40 or 15W-40 in my previous trucks. Isn’t 10W-30 a bit thin for this engine?
Our answer: We can assure you that a good 10W-30 diesel motor oil is safe for your engine. But let’s discuss an important detail to watch for on the oil bottle label. This detail will improve the odds that your engine will receive the best possible wear protection.
When buying diesel motor oil, look for the “API CK-4” designation. API CK-4 is the very latest diesel engine oil standard. It is backward-compatible with API CJ-4 and Chrysler MS-10902 (and therefore warranty-approved).
Is API CK-4 An Upgrade Over API CJ-4 Diesel Oils?
Yes. The API CK-4 standard has very lofty requirements in terms of oxidation resistance, shear stability and wear resistance. It is dramatically superior to API CI-4+ motor oils you may have used 15 years ago. It is even a significant step up from the previous API CJ-4 standard. One of the primary goals of the API CK-4 spec was to allow for the use of lower viscosity oils without sacrificing wear protection.
Why Did Chrysler Decide To Go With 10W-30 In The 6.7L Cummins?
The move toward thinner oils in engines, transmissions and differentials has been going on for years. The reason is simple. Automakers are under constant pressure to meet government-mandated fuel economy targets. Going to lower viscosity oils is a relatively simple way to make marginal mileage gains.
It may seem like wear control is being sacrificed to achieve slightly better fuel economy. This has not turned out to be the case. The motor oil industry is constantly raising the bar to strike that balance between improved fuel economy and satisfactory wear protection. The API CK-4 specification achieves this balance.
Is 5W-40 An Option In Newer 6.7L Cummins Engines?
All this being said, Chrysler does suggest that 5W-40 engine oil can be used in temperatures under 0°F (-18°C). So 5W-40 is certainly secondary option. If your engine is seriously modified or if the truck is used for extreme towing, 5W-40 is certainly viable. But again, under most conditions, 10W-30 diesel oil is perfectly safe.
Our Motor Oil Suggestions For RAM 6.7L Cummins Diesel Engines
We suggest AMSOIL synthetic diesel oils (of course). Some brands may meet the API CK-4 standard. AMSOIL CK-4 diesel products are designed to exceed this spec. Here are the options.
Signature Series Max-Duty Synthetic Diesel Oil is AMSOIL’s ultra-premium API CK-4 diesel motor oil line. It is available in both 10W-30 and 5W-40 for the Cummins 6.7. It is also available in 15W-40, 5W30 and 0W-40. This series is designed to out-perform on every front. The most important is wear control. Signature Series exceeds the Detroit Diesel Scuffing Test standard by 600%. It is also overbuilt for extended-drain capability.
Heavy-Duty Series Synthetic Diesel Oil is AMSOIL’s commercial-grade API-CK-4 diesel line. This line is also available in 10W-30 and 5W-40 for the Cummins 6.7L motor. It is also available in 15W-40. Heavy-Duty Series has a lower price tag for commercial fleets and cost-conscious consumers. But it still delivers top-notch wear protection. It beats the Detroit Diesel Scuffing Test standard by 400%.
In conclusion, check the bottle for the API CK-4 specification. You will receive the very latest diesel oil technology.
If you are interested in pricing for highly-effective AMSOIL Synthetic Diesel Engine Oils, contact us using the form on this page.
AMSOIL has added a new 10W-30 diesel oil to their elite Signature Series Max-Duty line. The full-synthetic Signature Series Max-Duty 10W-30 meets the latest API CK-4 specifications along with a multitude of industry standards.
Why Did AMSOIL Add 10W-30 Diesel Oil To Their Product Line?
There is a trend toward lighter viscosity motor oils in class 8 semi-unit engines. Engines such as Paccar MX13, Volvo D11, D13, D16 and Cummins X15 and X12 are compatible with 10W-30 motor oil. This is an effort to optimize fuel-economy. The use of lighter viscosity oils means that the industry has to be more diligent about wear control. Signature Series Max-Duty offers a world-class formula that demolishes industry wear tests such as the Detroit Diesel D13 Scuffing Test.
Ideal Applications For AMSOIL Signature Series Max-Duty 10W-30
Signature Series Max-Duty 10W-30 is ideal for newer or older diesel engines requiring a 10W-30 engine oil. Semi-truck owner/operators who are trying to maximize engine life might find this product particularly appealing. Reduced friction, extended oil change life and maximum engine life are attributes that they will appreciate.
This new 10W-30 meets the latest industry standards including API CK-4.
This product is certainly not the cheapest 10W-30 diesel oil out there. But we believe that it is the best. For those looking to protect their investment and make their engine last as long as possible, this synthetic diesel oil could be the best value on the road. Check out the product page at the link above for all of the features as well as the suitable applications and specifications.
Where To Buy AMSOIL Signature Series Max-Duty 10W-30 Synthetic Diesel Oil
We can ship Signature Series Max-Duty 10W-30 from 13 warehouse across the US and Canada. We also offer free shipping on qualified orders. There are commercial wholesale accounts for owner/operators and personal-use wholesale options as well.
Contact us for a price list using the form on this page.
A reader asks: I’ve got a 2003 Dodge Ram 2500 with the 5.9L Cummins engine. Should I use the older generation of CI-4+ diesel oils? Are the newer API CK-4 diesel oils good for this engine? My understanding is that these engines have flat tappet cams and I hear that the newer diesel oils do not have enough zinc to protect them.
Our answer: The short answer is that (for your older engine), virtually any of our diesel motor oils will be highly effective. The long answer may surprise you.
There is a common misconception that the newest diesel motor oils meeting the latest API CK-4 specification are somehow weaker or less robust than previous generations of diesel oils. This is patently false.
In fact, API CK-4 diesel oils are considerably more sophisticated and capable than diesel oils meeting previous specifications such API CI-4+. Older diesel oil formulas meeting API CI-4+ are weaker in terms of protective capabilities.
The introduction of the CK-4 spec was a tremendous challenge for motor oil makers. Diesel engines and their emissions components have become very sophisticated in recent years. The CK-4 requirements required oil makers to ramp up their game to meet much higher standards. Here are some of the upgrades of the API CK-4 spec over the previous CJ-4 spec.
Increase in high temperature capabilities
Improvement of piston and bore wear protection
Better deposit control
Resistance to degradation of hot and cold weather properties
Improved shear stability
Enhanced aeration resistance
Resistance to catalyst and particulate filter fouling
Improved oxidation resistance
What About AMSOIL Heavy Duty Series Vs. Older Diesel Oils?
AMSOIL Heavy Duty Diesel Series is a less expensive API CK-4 option to the flagship Signature Series Max-Duty Diesel Series. Heavy Duty Series was created as a budget-friendly option for fleets, the oil change installer market and those looking for a less expensive synthetic product.
We asked AMSOIL Technical Services how the API CK-4 AMSOIL Heavy Duty 15W-40 might compare to an older generation product like the API CI-4+ “AME” AMSOIL Heavy Duty Diesel and Marine 15W-40. Their answer was “It’s not even close”. While the Heavy-Duty Diesel And Marine 15W-40 is a very robust and competent product, development stopped when the API CI-4+ specification was replaced in 2007. The ball has been moved way down the field since then. So even the less expensive API CK-4 diesel oils are a step up over the previous generation.
Signature Series Max-Duty is considerably more advanced. It offers the most advanced synthetic base oil and additive technology available. As a result, Signature Series Max-Duty is an upgrade over Heavy-Duty Series in terms of wear control and service life.
What About Flat Tappet Cams?
Flat tappet cams are relatively common to many diesel engine types. The biggest concern with flat tappet cams is wear protection. Specifically, does the motor oil contain enough ZDDP (Zinc Dialkyl Dithio Phosphate) and phosphorus?
Flat tappets in diesel engines are less of a concern than having flat tappet cams in something like a gasoline-powered street rod motor. Street rods and drag racers run at much higher RPM and tend to have much heavier valve springs compared to stock diesel engines. Also, modern passenger car/gasoline motor oils have much lower zinc and phosphorous limits. These levels are insufficient for flat tappet wear protection. So owners of gasoline engines with flat tappet camshafts have to be very mindful of their motor oil choice.
This is not a concern with diesel engine oil. Diesel motor oils are designed for all diesel engine types. Contrary to popular belief, the newest API CK-4 spec has not limited zinc and phosphorous to dangerously low levels with 40-weight viscosities. This would include 0W-40, 5W-40 and 15W-40, etc.
The API CK-4 AMSOIL Signature Series Max-Duty 5W-40 and 15W-40 has zinc levels over 1300 and phosphorus levels above 1200 ppm. Similarly, the AMSOIL Heavy- Duty 5W-40 and 15W-40 has zinc over 1100 ppm and phosphorus over 1000 ppm.
To contrast, the older AMSOIL Heavy Duty Diesel and Marine 15W-40 (API CI-4+) has 1377 PPM ZDDP and 1267 ppm phosphorus. This doesn’t necessarily mean that it will protect flat tappet engines better than the API CK-4 oils. The zinc and phosphorus level comparisons are a moot point. The newer API CK-4 chemistry is miles ahead of the older API CI-4+ formula. The newer CK-4 options will provide considerably better wear protection.
Conclusion
To sum up, do not be concerned about using the latest API CK-4 diesel motor oils in older engines. They are very much backward compatible with older engine designs and are a giant step forward in terms of wear control.
AMSOIL has released more information on their brand new line of synthetic diesel engine oils. This extensive new line-up will be released in early 2017 and will cover a wide variety of industry specs and applications. The most notable specification is the new API CK-4 heavy-duty diesel motor oil standard.
AMSOIL’s 2017 API CK-4 Diesel Engine Oil Line-up
Latest News On Ford Power Stroke Engine Oil Controversy
You may have heard about Ford claiming that the new API CK-4 diesel oils can cause damage in Power Stroke diesel engines. Some API CK-4 oils have a phosphorus content of less than 1000 parts per million (ppm). Ford is contending that their testing shows accelerated valve train wear with some CK-4 formulations. For now, Ford is recommending the use of engine oil meeting the current API CJ-4 spec which has a phosphorous limit of 0.12% by volume (this works out to 1000 to 1200 ppm).
Here is why there is much confusion. It used to be that if an engine oil had both the API heavy-duty diesel and passenger car specifications on the label, the oil maker could abide by the higher phosphorous limit of the diesel spec. Some are suggesting that this loophole is now closed, implying that if an oil maker has both API CK-4 and the API SN (passenger car spec) on the label, the lower phosphorous limit (800 ppm) of the passenger car SN spec has to be followed. This is only partially true.
The API tells us that the phosphorous limit loophole still exists for most grades of heavy-duty diesel engine oil. The important distinction is that ILSAC viscosity grades (0W-30, 5W-30 and 10W-30) will have the lower phosphorous limit of 800 ppm, if a product carries the API SN spec along with API CK-4. Thankfully, 40-weight diesel engine oils can still have the API SN designation and abide by the higher phosphorous limit of the diesel spec.
There are indications that when the API SP passenger motor oil specification is introduced in 2018, diesel oils carrying both the SP and CK-4 specs will have to abide by the SP phosphorous limit. The way around this will be for an engine oil to carry the previous API SN spec instead of SP.
AMSOIL’s New API CK-4 Oils And Phosphorous Content
The only AMSOIL product that will have a lower phosphorous limit is the upcoming AMSOIL Signature Series 5W-30 Max-Duty Synthetic Diesel Oil. As a 5W-30 carrying the API SN spec, it has to abide by the SN phosphorus limit of 800 ppm. The phosphorus limitation does not apply to the rest of the new diesel engine oils, so there will be zero issues with using them in Ford Power Stroke Diesels.
All but the Signature Series 5W-30 Max-Duty will carry the new Ford WSS-M2C171-F1 spec which will designate them as safe and approved for all model year Ford Power Stroke engines. But that doesn’t mean that the Signature Series 5W-30 Max-Duty will be a lightweight. AMSOIL has indicated that it is loaded with anti-wear technology and will eventually be proven safe for Ford Power Strokes as well. But for now, they are leaving the Ford WSS-M2C171-F1 spec off of the label.
Note that the new AMSOIL Heavy-Duty 10W-30 Synthetic Diesel Engine Oil does not carry the API SN specification. Being a 10W-30, had they marketed it as an API SN product (for passenger car service), they would have had to defer to the 800 ppm phosphorous limit for API SN. Heavy Duty 10W-30 carries only heavy-duty diesel oil specs such as API CK-4. It also lists the Ford WSS-M2C171-F1 spec, making it suitable for Power Stoke engines.
Specifications Covered By the 2017 AMSOIL Synthetic Diesel Engine Oil Series
Here is a brief description of each of the brand new API CK-4 AMSOIL Diesel Engines Oils. This line will launch in February, 2017.
AMSOIL Signature Series 5W-30 Synthetic Diesel Engine Oil
This 5W-30 product is part is the “Max Duty” Signature Series of synthetic diesel oils. It will be a premium synthetic choice for modern diesel applications requiring a 5W-30. This product will not be replacing the “HDD” Series 3000 5W-30 Diesel Engine Oil. HDD 5W-30 will still be available for older diesel engines requiring the API CI-4+ spec. Here are the specifications covered by Signature Series Diesel 5W-30.
API CK-4/SN, CJ-4, CI-4+, CF
ACEA E9, E7, E6
Chrysler MS 10902
Mack EOS-4.5, EO-O
Detroit Diesel DFS 93K222, DDC 93K218, 93K215, 93K214
Caterpillar ECF-3, ECF-2, ECF-1-a
Cummins CES20086, CES20081
Volvo VDS-4.5, VDS-4, VDS-3
MB 228.51, 228.31
MTU Type 3.1, 2.1, II, I
MAN 3677, 3575
JASO DH-2
Renault RLD-4, RLD-3
Deutz DQC IV-10 LA, DQC III-10 LA
Scania LA-2
AMSOIL Signature Series 0W-40 Synthetic Diesel Engine Oil
At long last, AMSOIL will offer a heavy-duty 0W-40 diesel engine oil. This premium 0W-40 will be ideal for diesel engines that operate in extreme cold. It will also be suitable for year-round use. Here are the specifications covered by Signature Series Diesel 0W-40.
API CK-4/SN, CJ-4, CI-4+, CF
ACEA E9, E7
Chrysler MS 10902
Ford WSS-M2C171-F1
Mack EOS-4.5, EO-O
Detroit Diesel DDC 93K218, 93K215, 93K214
Caterpillar ECF-3, ECF-2, ECF-1-a
Cummins CES20086, CES20081
Volvo VDS-4.5, VDS-4, VDS-3
MTU Type 2.1, II, I
MAN 3575
JASO DH-2
Renault RLD-4, RLD-3
Deutz DQC III-10 LA
Ford WSS-M2C171-F1
AMSOIL Signature Series 5W-40 Synthetic Diesel Engine Oil
This product will replace “DEO” AMSOIL Premium 5W-40 Synthetic Diesel Engine Oil. This new API CK-4 5W-40 will be the go-to product for diesel pick-up owners looking for a premium motor oil. As it covers the Chrysler MS 10902 spec, it will also be the premium choice for Ram EcoDiesel pick-ups. The Ford WSS-M2C171-F1 spec will also be covered by this oil, making it a great option for all model year Ford Power Stroke engines.
API CK-4/SN, CJ-4, CI-4+, CF
ACEA E9, E7
Chrysler MS 10902
Ford WSS-M2C171-F1
Mack EOS-4.5, EO-O
Detroit Diesel DFS 93K222, DDC 93K218, 93K215, 93K214
Caterpillar ECF-3, ECF-2, ECF-1-a
Cummins CES20086, CES20081
Volvo VDS-4.5, VDS-4, VDS-3
MB 228.31
MTU Type 2.1, II, I
MAN 3575; JASO DH-2
Renault RLD-4, RLD-3
Deutz DQC III-10 LA
Allison TES-439
Scania LA-2
AMSOIL Signature Series 15W-40 Synthetic Diesel Engine Oil
Signature Series 15W-40 will replace the API CJ-4 “DME” AMSOIL Premium 15W-40 Synthetic Diesel Engine Oil. This will be AMSOIL’s premium 15W-40 for pick-ups and heavy-duty engines of all model years.
API CK-4/SN, CJ-4, CI-4+, CF
ACEA E9, E7
Chrysler MS 10902
Ford WSS-M2C171-F1
Mack EOS-4.5, EO-O
Detroit Diesel DFS 93K222, DDC 93K218, 93K215, 93K214
A 10W-30 diesel motor oil is often suggested for Ford Power Stroke engines in colder climes. The new Heavy-Duty Protection Synthetic 10W-30 will meet the Ford WSS-M2C171-F1 spec making it a safe choice for diesel engines in F-Series trucks. This new diesel 10W-30 will replace AMSOIL OE 10W-30 Synthetic Diesel Engine Oil.
API CK-4, CJ-4, CI-4+, CF
ACEA E9, E7
Ford WSS-M2C171-F1
Mack EOS-4.5, EO-O
Detroit Diesel DFS 93K222, DDC 93K218, 93K215, 93K214
This new 5W-40 Synthetic Diesel Oil will be moderately priced and a versatile addition to the line-up. It will cover the full spectrum of industry specs including API CK-4, Chrysler MS 10902 and Ford WSS-M2C171-F1. This will make it a great choice for budget-minded Ford Power Stroke and Ram EcoDiesel owners.
API CK-4/SN, CJ-4, CI-4+, CF
ACEA E9, E7
Chrysler MS 10902
Ford WSS-M2C171-F1
Mack EOS-4.5, EO-O
Detroit Diesel DFS 93K222, DDC 93K218, 93K215, 93K214
This new API CK-4 15W-40 will replace AMSOIL OE 15W-40 Synthetic Diesel Engine Oil. It will be moderately priced and ideal for fleets and commercial use.
API CK-4/SN, CJ-4, CI-4+, CF
ACEA E9, E7
Chrysler MS 10902
Ford WSS-M2C171-F1
Mack EOS-4.5, EO-O
Detroit Diesel DFS 93K222, DDC 93K218, 93K215, 93K214
Ford is concerned that the new API CK-4 diesel oil spec does not mandate enough wear control additives. But fear not, there is a distinct work-around.
There’s a bit of controversy brewing regarding the brand new API diesel engine oil specifications that debut for 2017. Starting in December, the American Petroleum Institute (API) will start granting licenses for two new diesel engine oil specs. The API CK-4 specification will supersede the API CJ-4 spec that debuted back in 2006. A new low-viscosity spec for over-the-road transport trucks call API FA-4 will also be released. So why is there a controversy?
Ford has conducted in-house testing on API CK-4 and FA-4 formulations in their Powerstroke diesel engines. They were not pleased with the results. The FA-4 oils simply did not provide effective viscosity protection (read: too thin) and some CK-4 oils did not contain enough phosphorous to provide acceptable valve-train wear protection.
Phosphorous is a vital anti-wear agent in diesel engine oils. The current API CJ-4 spec mandates a maximum phosphorous content of 0.12%. This generally works out to over 1000 parts per million (ppm). Ford is finding that motor oil with a phosphorous content under 1000 ppm is causing excessive wear. The new API CK-4 spec mandates a phosphorous limit of 0.08%. This can leave some formulations with less than the 1000 ppm that Ford would like to see. But there is a way to avoid the new low phosphorous limit and still use API CK-4 oils in Powerstroke diesel engines.
Here is the vital distinction. The API is suggesting this lower phosphorous limit when a motor oil maker wishes to carry both the API CK-4 diesel specification AND the API SN passenger car/gasoline engine specification on the label. As the API SN limit for phosphorous is 0.8%, the API is requiring that any diesel engine oil also carrying the passenger car/gasoline engine spec must meet this lower limit. The good news is that “stand alone” diesel engine oils that do not label their product as meeting the API SN (or any other passenger car spec) can have a higher phosphorous limit of 0.12%.
In other words, as Ford is suggesting that the previous generation API CJ-4 oils do contain an acceptable allotment of phosphorous, “diesel only” API CK-4 oils should also be fine. Ford is coming up with their own diesel spec to clear up any confusion. It will be called Ford WSS-M2C171-F1. We can speculate that motor oils meeting this spec will either be API CK-4 oils that do not have the API SN designation or older API CJ-4 products.
API CK-4 Phosphorous Issue Update- January 6th, 2017
Further clarification from the American Petroleum Institute. They tell us that 40-weight diesel engine oils (such as 5W-40, 15W-40, 0W-40) can have both the API CK-4 and API SN specs and still abide by the higher API CK-4 phosphorus limit. On the other hand, 0W-30, 5W-30 and 10W-30 engine oils carrying both the API SN and API CK-4 specs have to abide by the lower SN phosphorous limit of 800 ppm.
AMSOIL Offers Safe API CK-4 Engine Oil For Ford Powerstroke
AMSOIL’s 2017 API CK-4 Diesel Engine Oil Line-up
AMSOIL is releasing a full suite of brand new diesel engine oils in early 2017 that will meet the API CK-4 spec. Most will also be Ford WSS-M2C171-F1 compliant. We can only speculate as to whether these oils will also carry that API SN gasoline engine specification to make them more convenient for fleets. We know that the upcoming Signature Series Max Protection 5W-30 will also carry the API SN spec. It will be interesting to see if this product also carries the Ford spec. We will go out on a limb and guess that most of the upcoming line-up will be “diesel only” so that they can contain the 0.12% dose of phosphorus. We’ll know more in the weeks to come. AMSOIL has already indicated that they will have API CK-4 product choices that will be undeniably safe for all model year Ford Powerstroke engines.
Conclusion
The API is suggesting that the CK-4 oil standard will offer improvements in terms of oil longevity, shear stability and deposit control over the current CJ-4 spec. Once Ford releases their new diesel oil specification, Powerstroke owners should have an easier time finding safe formulations with the very latest motor oil technology.