Costco Chevron Delo 400SDE CK-4/SN SAE 15W40 Diesel Engine Oil in a Gasoline Engine

No idea but it may be the right lubricant.

Engine builder of my 1965 Corsa says Shell Rotella 15~40 Diesel type T which has a zinc additive. I take his advice.

Hi AMuzi,

Interesting. Verrrry interesting. Thank you for that purposefully helpful information that "diesel oil" may be ok (or even "good"?) for gas engines.

NOTE: Always (always!) we assume it meets API & SAE specifications! (i.e., viscosity range & service letter, e.g., SA, SB, SC... SP).

The problem I'm having is finding reliable public cites that I can believe. o For example, this says you can do it, but where are the underlying facts? o Can I Use Diesel Oil in My Gas Engine?

The viscosity isn't all that important (IMHO), as this is Silicon Valley, where almost _any_ viscosity range will work just fine; so it's only the service range that matters (currently CK-4 for diesel, & SP for gas). Originally published June 10, 2016.

In that AMSoil blog, they say that the additives are the same, and that the additives are different (in general, diesel having higher requirements).

This is a "yahoo" hit, so we need to use a bit of salt when we read it...

o Can I put diesel engine oil in a gas engine car?

What comes up as the key "worry" is the gas-engine catalytic converter. o What comes up as the "benefit" is the ZDDT zinc additives in diesel oil.

Likewise, salt is needed as this one came from "Answers"... o Can you put diesel oil in a gas engine?

Where they discuss the viscosity, as if that's critically important o Where in my humblest of opinion, people harp too much on viscosity

Salt is also required since this next hit is a "Quora" article: o Is it possible to use diesel engine oil in a petrol engine car?

Where, again, they harp on the viscosity, which I think, IMHO anyway, is the least of the problem, particularly for older cars in Silicon Valley.

Looking for facts, I found this article reputedly explaining differences: o What Is the Difference Between Gas & Diesel Engine Motor Oil?

(1) "diesel oil has a higher zinc dialkyl dithiophosphate (ZDDP) level than gasoline engine oil, to form a film on bearings and the camshaft to prevent wear. ZDDP contains both zinc and phosphorous. This content is the leading reason diesel oil can't be used in gas engines."

(2) "Diesel oil is more viscous" (which is the least of my worries)

(3) "The level detergents and other additives is higher for diesel to combat the higher soot..."

"diesel oil's greater concentration of detergent, or scrubbing agent, can remove manufacturer's deposits on the cylinder wall that help seal the combustion gases. This can lead to smoking inside the engine, which can in turn damage the catalytic converter."

(4) "higher additive levels in diesel oil means you can drive further before they degrade to levels too low for a gas engine"

As for the question of "Use of Diesel Oil in Gas Engine", they say:

(A) "You can use diesel in cars older than model year 1975, when catalytic converters were first mandated."

(B) "You must match the viscosity" (which is the least of my worries)

(C) "If you do decide to use one type of oil in the other type of engine, you can tell which is for gas engines by the "S" in the oil can coding ("S" for "servicing"). "C" is for diesel engines ("C" for "commercial")"

Intuition is always misleading when dealing with highly marketed products o So I delved a bit deeper into independent sources from Chevron marketing

Apparently this is the Petroleum Quality Institute of America's test: o Chevron Delo 400 SDE SAE 15W-40 Heavy Duty Deisel Engine Oil [sic]

I don't know how much we can trust this web site, but they tested the oil for a variety of the specifications, and they seem to have marked this oil in the higher than middle point on most of the tests they performed (but, interestingly so, not high or low on any of them).

NOTE: It might be a "good" oil, perhaps; but perhaps not a "great" oil?

Interestingly, the standard for "phosphorus" is 1,200 ppm (mg/liter) where this Chevron Delo 400 SDE oil was tested at 779 ppm (779 mg/liter).

Unfortunately there's no listed limit for "zinc", where this Chevron Delo

400 SDE oil was tested at 817 ppm (817 mg/liter).

Also quite unfortunately, they mention nothing, per se, about its use in gasoline engines (although they seem to have tested API SN requirements).

Given that MARKETING's job is to make you intuit what isn't true o I'm digging further for _independent_ sources of information on this oil

This page claims to be: "The independent resource for information and insights on the quality and integrity of lubricants in the marketplace"

They claim the oil meets the stated J300 specs and they claim they found:

Detergents: o Calcium (ppm) 1,590 o Magnesium (ppm) 722 o Sodium (ppm) 13 o Barium (ppm) <1 o TBN, mg KOH/g (ASTM D2896) 9.63

Antiwear Additives: o Phosphorus 1,200 Max -a 711ppm o Zinc 807ppm o Molybdenum 131ppm o Titanium <1ppm o Boron 370ppm

Contaminants: o Silicon* 6 ppm o Silver <1 ppm o Aluminum 5 ppm o Chromium <1 ppm o Iron 1 ppm o Nickel <1 ppm o Lead <1 ppm o Antimony <1 ppm o Tin <1 ppm o Copper <1 ppm o Cadmium <1 ppm o Vanadium <1 ppm o Potassium <1 ppm o Manganese <1 ppm o Lithium <1 ppm

*Whereas silicon in the form of polydimethylpolysiloxane is commonly used as an antifoamant in motor oil, such use typically does not exceed 10ppm in new motor oil. Levels much above indicate possible contamination with abrasive material, silicone-based sealers, and/or transformer and hydraulic oil.

Engines with flat tappet cams will benefit from an oil with higher levels of ZDDP. As a consequence, many people with older cars use either an oil designed for diesel engines with high ZDDP, or use an additive with extra ZDDP. This was discussed extensively in this group twenty years or so back.

--scott

I think I solved the problem set. o I called "the man" at Chevron himself, 1-800-822-5823 to ask directly

They took a while to get me a suitable engineer but he was pretty good. o He said NOT to use it in gasoline engines that have a catalytic converter

Specifically he said the Phosphorous and Zinc are rather high in this oil o Neither will do any good to a catalytic converter in a state that smogs

Where we are, every car (older than, oh, about 1975) is smog'd each 2 years o So it's not a good oil for a car that has a cat that gets smogged.

The oil is actually good oil (but not synthetic despite the "isosyn" label) o Some Zn & P is needed; but gasoline engine oils have lower limits.

He also said the 15W viscosity probably doesn't meet OEM specs for cars. o Although he agreed the 15W only happens for a couple of minutes, at most.

So there's the answer.... o Now I have to ask my neighbor what cars he puts it in to check the cat!

Hi Scott,

Thanks for that information about zinc dialkyl dithiophosphate (ZDDP), which contains both Zn & P, neither of which is good for a cat.

I had never even heard of ZDDP until today, but the guy I just spoke to at Chevron (1-800-822-5823) mentioned that it's what is both making it good for the diesel engines, but bad for catalytic converter gas engines.

He did say it's a longer-lasting better oil for gasoline engines that do not have the problem of passing a smog check (he made it a point to ask if my state has smog, for example).

So if it wasn't for the cat, it would be a "better" oil than a conventional gasoline engine oil (everything else being equal).

He did mention though that it's not "synthetic" by Chevron's definition, but that it uses "synthetic technology", and hence the "isosyn" label.

The end result is that it's a good oil apparently, for diesels, and it's even a better oil for older gas cars that don't have catalytic converters, and, even for newer gas cars that do, as long as the cat isn't smog'd periodically (assuming the viscosity is what you want).

But it's just not a good choice for modern gas engine vehicles with cats.