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(photo credit: trucktrend.com)

EcoDiesel engines are being switched from 5W-30 motor oil to 5W-40 and apparently there is a good mechanical reason for it.

Update August 2016: We now offer an aftermarket oil filter for the Ram 1500 and Jeep Grand Cherokee with the EcoDiesel engine

There’s an online commotion brewing regarding a technical service bulletin (TSB) released by Fiat-Chrysler (FCA) on July 20, 2016. The bulletin pertains to an engine oil upgrade from 5W-30 to 5W-40 for the 2016 Ram 1500 and Jeep Grand Cherokee models with the EcoDiesel engine. This bulletin directs Chrysler-Jeep dealers to drain the factory-fill 5W-30 motor oil and replace it with 5W-40 motor oil. You can view the official service bulletin here.

Addendum cards have also been shipped to dealers which are to be added to owner’s manuals. These cards recommend the use of synthetic 5W-40 engine oil that meets the FCA Material Standard MS-10902 and API CJ-4 specifications.

Some Dodge dealers we spoke to seem to think that this recommendation applies only to 2016 EcoDiesel models. Based on the language in the bulletin, it’s easy to arrive at that conclusion. But there is more to this story.

Why Is 5W-40 Now Recommended For The EcoDiesel Engine?

It took some digging, but we think we may have found the answer. We spoke to several Dodge dealers and also FCA Customer Care. Few had even heard of the engine oil changeover or they simply read back the bulletin. But a service manager at a Salt Lake City Dodge dealership had heard all about the reason for this oil switch from an FCA warranty official. Apparently the 3.0L EcoDiesel engine is experiencing an unsettling number of main bearing failures. FCA is laying the blame on the thin viscosity of 5W-30 engine oil. They believe that the thicker viscosity of 5W-40 engine oil will cure this issue. This service manager suggested that all model years will have a 5W-40 recommendation and that 5W-30 engine oil will be obsolete for the EcoDiesel engine.

Will 2014 And 2015 EcoDiesel Engines Require 5W-40 Motor Oil?

This seems to be all but official, but you wouldn’t know it if you called your local Jeep or Ram dealer. The latest revisions of the 2014 and 2015 owner’s models now suggest “SAE 5W-40 Synthetic, API CJ-4”. You can download a copy at this page. Pick a model year of the 1500 model and then click on download of the “Diesel Supplement”. See page 120 for the 2014 model and page 122 of the 2015 model.

If you own a 2014 or 2105 EcoDiesel model, press your dealer for a definitive engine oil viscosity recommendation before your next oil change.

An Updated AMSOIL EcoDiesel Motor Oil Recommendation

AMSOIL Synthetic 5W-40 API CJ-4 Diesel OilDue to the vague disclosure of this oil recommendation change by FCA, the AMSOIL application guide is not completely up to date (as of publication of this post). They are still showing the AMSOIL European Car Formula Improved ESP Synthetic 5W-30 for the 2014 and 2015 EcoDiesel Ram 1500 and Grand Cherokee. For 2016 EcoDiesel models, the application guide now suggests AMSOIL Premium 5W-40 Synthetic Diesel Oil. AMSOIL Premium Diesel 5W-40 meets the API CJ-4 and Chrysler MS-10902 specs. We can offer this synthetic diesel 5W-40 oil at wholesale prices shipped right to your door in Canada or the United States.

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