Farm Industry News Blog

Dummies Guide to diesel engine oil

My recent trip to watch an engine teardown in Greensborough taught me a lot about oil. In order to cover the topic I had to do a little research before and after I wrote the Shell Rotella piece on its new experimental oil it says will be the wave of the future. Here’s a cheat sheet to the acronym-rich terminology of engine oil and the new PC-11 category you’ll need to study up on when it hits the market in the next year or two.


  1. PC-11: Stands for Proposed Category (PC) 11, a new category of engine oil that is low-viscosity (see def.) and more heat-resistant than the current engine oil on the market to handle the extra 10C in heat produced by the new Tier 4 engine technology for reduced emissions. The big benefit of this oil for buyers? Increased fuel economy without sacrificing durability.
  2. CJ-4: The current category of diesel engine oil that has been around for 10 years and will soon be replaced by PC-11.
  3. Viscosity: Basically means the thickness of the oil. Which flows faster? Honey or water?
  4. Fluidity: The reciprocal of viscosity, usually symbolized by φ = 1 / μ or F = 1 / μ, depending on the convention used. (Thanks a lot Wikipedia. Now it’s suddenly clear.)
  5. HTHS: High temperature high shear. Type of oil that improves fuel economy and durability of an engine.
  6. ASTM: American Society for Testing and Materials
  7. API: American Petroleum Institute
  8. HDDEO: Heavy Duty Diesel Engine Oil
  9. Shear stability: A measure of the amount of viscosity an oil may lose during operation. Oil experiences very high stresses in certain areas of the engine such as in the oil pump, cam shaft area , piston rings, and any other areas where two mating surface areas squeeze the oil film out momentarily . (Source: Bob The Oil Guy.)
  10. 10w30: Seriously, don’t even go there. It’s more complicated than you might think.

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Discuss this Blog Entry 5

John Davidson (not verified)
on May 28, 2014

Been using Shell Rotella T ever since I saw my first engine tear down of a Cat engine in a semi with over 700,000 miles on it. You could eat off the bottom of the pan. I switched all my engines diesel and gas to Rotella T the next time I bought oil and been on it since the early 1970's. Good stuff! Had a IHC 1456 with over 10,000 hrs on it and a 856 with over 15,000 hrs on it. I had been through the back ends but NEVER touched the engines and they ran way over stock horsepower their whole life.

on Jun 16, 2014

Engine oil is one of the most essential things for any engine; it helps to boost our engine's performance and keep engine better forever. Therefore in every vehicle we have found that engine oil should be change at regular intervals; otherwise it directly or indirectly affects engine's performance and vehicle's efficiency.
Mini Cooper repair Manhattan Beach

on Aug 14, 2014

We can understand the importance of engine oil and how much essential it is for our vehicles. We have petrol engine, diesel engine, gasoline and other types of engines and every engine has its unique feature. But most probably people are using diesel and gasoline engine instead of petrol engine; and from here also we can get suitable information about the importance of diesel engine. Really it is quite beneficial for us and every vehicle owner should learn certain facts from here.
BMW repair Boulder, CO

on Aug 30, 2014

Engine oil is the fuel of different cars. It's just like the food for the car engines. The oil is burnt itself to produce energy which later supply motion to the engine. In this way the diesel engine starts. The diesel engine gives more efficiency & performance in road as the engines are powerful. The oil is available in petrol pumps & other outlets. The engines require regular service to move for long time.
BMW Repair Franklin, MA

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