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New 15W-30 oil may offer benefits in ag applications

Chevron introduces a “severe duty” oil for diesel engines

Chevron’s new Delo 15W-30 diesel engine oil is designed for “severe duty” applications, and offers a potential fuel economy improvement.

Most of the farm machines at work this summer likely have 15W-40 oil sloshing around in their engine crankcases. That’s been the standard summer oil for some time. But in April Chevron introduced a new lighter-weight, conventional oil that can replace 15W-40 in many applications. And according to Harry Hazen, North American marketing manager for Chevron, it will do a better job under “severe duty” conditions.

It’s their Delo SD SAE 15W-30. This oil complies with the newest API CJ-4 classification standards, but it’s also backward compatible with the previous service categories required by older engines.

“This product is designed for what we term as severe duty applications,” Hazen says. “What those are by our definition are stop-and-go operations, frequent start up and shut down of the engine, and frequent engine cycling to adjust to varying loads.”

With so much emphasis lately on reducing fuel consumption, many truck fleet operators are instructing their drivers to reduce idle times by shutting diesel engines off as frequently as possible. While there are cost savings to be had with that practice in both on- and off-road applications, it can be hard on engine oil, degrading it prematurely.

“There is a potential down side,” Hazen cautions. “Because those types of operations can increase the temperature of the oil. And by increasing the temperature of the oil, you could accelerate such things as oxidation. Oxidation is a breakdown of the oil, and it can result in deposits and other things that can impact component life. This (15W-30) product is specifically designed for those severe duty applications. It will resist oxidation better than other oils on the market.”

  • Read more: Is synthetic engine oil worth the extra cost?

Another benefit of going to a lighter weight 15W-30 instead of 15W-40 is it allows the engine to sip a little less fuel even during general operation.

“15W-40 for a long time has been the standard in both on- and off-highway type applications,” he says. “Recently in the on-highway applications, we’ve seen people moving to a 10W-30. And the reason for that is they want to reduce their fuel consumption. And a 10W-30 will give them some fuel consumption savings.”

“(With the 15W-30) we’ve realized 1.8 per cent fuel improvement, which is comparable to a 10W-30. What we say is with 15W-30 you can get comparable fuel savings as with a 10W-30, and we tested that in Class 6 trucks. That’s something for folks to consider. But the caveat I like to throw in there is fuel consumption is very much tied to the driver as well. The driver or operator has a lot of influence on fuel economy.”

Oil change intervals

According to Hazen, a 15W-40 oil would be better suited to longer oil change intervals than the lighter weight 15W-30. But, he adds, if you are actually operating machinery in conditions that meet Chevron’s severe duty definition, trying to stretch out those intervals out no matter what oil is used may be false economy.

“That (15W-40) would be my recommendation if they’re looking to extend drain intervals,” he says. “But if you can call it severe duty, I wouldn’t look to extend drain intervals.”

And, he says, owners should always consult the vehicle manufacturer’s recommendations for viscosity selection and oil change intervals.

To see if your circumstances meet Chevron’s severe duty definition, you can go online to their new website,, and take the quiz.

About the author


Scott Garvey

Scott Garvey is a freelance writer and video producer. He is also the former machinery editor at Grainews.



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