jjk454ss
Bronze Member
Is there really a need to use motor oil that says Diesel Engine Oil? I changed my oil and didn’t use it.
Diesel Oil
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Ortimber
Platinum Member
Diesel oils deal with soot control better than a non diesel specific oil. There are also other additives/properties that make it different than non diesel spec oil. You probably have done no harm, but long term I’d suggest using diesel spec only.
Cat_Driver
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Comparing Gasoline and Diesel Engine Oils
Comparing Gasoline and Diesel Engine Oils
Jeremy Wright
Emissions and the Catalytic Converter
A catalytic converter is a housing that contains porous metal filler located between the engine and muffler in the exhaust system. Its role is to convert toxic emissions coming from the engine to stable byproducts before they enter the atmosphere. Some of the byproducts of combustion (lead, zinc and phosphorus) can severely cripple the converter’s ability to perform this job. Therein lies the first major difference between the oils.
Diesel engine oils have a higher anti-wear (AW) load in the form of zinc dialkyldithiophosphate (ZDDP). The catalytic converters in diesel systems are designed to be able to deal with this problem, while the gasoline systems are not. This is one of the main reasons you don’t want to use a diesel engine oil in your gasoline engine. If your automobile was built prior to 1975, there is a good chance it does not have a catalytic converter, and thus the above statements do not apply.
Viscosity
Viscosity is the single most important property of a lubricant. When I am working as a consultant and designing a lubrication program, one of the first steps I take is to calculate required viscosities. Getting the right viscosity is of the utmost importance. The selected viscosity needs to be pumpable at the lowest start-up temperature while still protecting the components at in-service temperatures.
Typically, diesel engine oil will have a higher viscosity. If we were to put this higher viscosity in a gasoline engine, several problems might arise. The first is heat generation from internal fluid friction. I’ve covered before how this heat affects the life of an oil. A good rule of thumb is that for every 10 degrees C you increase the temperature, you cut the life in half.
The second problem is the low-temperature pumpability of this higher viscosity. During cold starts, the oil may be very thick and difficult for the oil pump to deliver to the vital engine components in the lifter valley. This most certainly will lead to premature wear, as the components will be interacting without the benefit of lubrication.
Additive Levels
Diesel engine oil has more additives per volume. The most prevalent are overbase detergent additives. This additive has several jobs, but the main ones are to neutralize acids and clean. Diesel engines create a great deal more soot and combustion byproducts. Through blow-by, these find their way into the crankcase, forcing the oil to deal with them.
When you put this extra additive load in a gasoline engine, the effects can be devastating to performance. The detergent will work as it is designed and try to clean the cylinder walls. This can have an adverse effect on the seal between the rings and liner, resulting in lost compression and efficiency.
So how do you know if an oil has been designed for gasoline or diesel engines? When reading a label, look for the API (American Petroleum Institute) doughnut. In the top section of this doughnut will be a service designation. This designation will either start with an “S” (service or spark ignition) for gasoline engines or a “C” (commercial or compression ignition) for diesel engines.
Comparing Gasoline and Diesel Engine Oils
Jeremy Wright
Emissions and the Catalytic Converter
A catalytic converter is a housing that contains porous metal filler located between the engine and muffler in the exhaust system. Its role is to convert toxic emissions coming from the engine to stable byproducts before they enter the atmosphere. Some of the byproducts of combustion (lead, zinc and phosphorus) can severely cripple the converter’s ability to perform this job. Therein lies the first major difference between the oils.
Diesel engine oils have a higher anti-wear (AW) load in the form of zinc dialkyldithiophosphate (ZDDP). The catalytic converters in diesel systems are designed to be able to deal with this problem, while the gasoline systems are not. This is one of the main reasons you don’t want to use a diesel engine oil in your gasoline engine. If your automobile was built prior to 1975, there is a good chance it does not have a catalytic converter, and thus the above statements do not apply.
Viscosity
Viscosity is the single most important property of a lubricant. When I am working as a consultant and designing a lubrication program, one of the first steps I take is to calculate required viscosities. Getting the right viscosity is of the utmost importance. The selected viscosity needs to be pumpable at the lowest start-up temperature while still protecting the components at in-service temperatures.
Typically, diesel engine oil will have a higher viscosity. If we were to put this higher viscosity in a gasoline engine, several problems might arise. The first is heat generation from internal fluid friction. I’ve covered before how this heat affects the life of an oil. A good rule of thumb is that for every 10 degrees C you increase the temperature, you cut the life in half.
The second problem is the low-temperature pumpability of this higher viscosity. During cold starts, the oil may be very thick and difficult for the oil pump to deliver to the vital engine components in the lifter valley. This most certainly will lead to premature wear, as the components will be interacting without the benefit of lubrication.
Additive Levels
Diesel engine oil has more additives per volume. The most prevalent are overbase detergent additives. This additive has several jobs, but the main ones are to neutralize acids and clean. Diesel engines create a great deal more soot and combustion byproducts. Through blow-by, these find their way into the crankcase, forcing the oil to deal with them.
When you put this extra additive load in a gasoline engine, the effects can be devastating to performance. The detergent will work as it is designed and try to clean the cylinder walls. This can have an adverse effect on the seal between the rings and liner, resulting in lost compression and efficiency.
So how do you know if an oil has been designed for gasoline or diesel engines? When reading a label, look for the API (American Petroleum Institute) doughnut. In the top section of this doughnut will be a service designation. This designation will either start with an “S” (service or spark ignition) for gasoline engines or a “C” (commercial or compression ignition) for diesel engines.
Thanks, I wasn稚 too worried since I just changed it and only used it a couple hours since. But I wonder if I should drain and fill with the Diesel Oil? The article above talks about different viscosity which sounds fishy since the viscosity is listed and I would think wouldn稚 change based on wether it says Diesel or not.
If there痴 additives, I wonder if I can:should buy an additive and use the oil i already used?
LD48750
Veteran Member
If it was me, I would leave it until the next oil change.
That would be next spring & I wouldn't have very many hours on it anyway.
100/150 Hrs isn't much when you consider how many hours a car or truck runs to get 7500/10000 miles on it between oil changes.
So I picked up 15w40 diesel oil to replace the 10w30 gasoline engine oil. Should I bother taking off the oil filter and draining it to get rid of as much of the existing oil as possible? I feel like it would hold so little, but changing viscosity should I drain out whatever it holds?
I guess it would only take 2 minutes, but....
I guess it would only take 2 minutes, but....
Agvg
Elite Member
Would be a much better oil then the antique 15w/40 oil. But suppose you are in the us so it might not be std with diesel approval on ordinary oil. What does the label on the oil you are using say?
Robin Veerman
Veteran Member
I use AMSOIL 5w40 in my Kioti here in Ontario Canada. It can get real cold in the winter and real hot during the summer. This oil is full synthetic and has both diesel (C***) and gas (S***) designations. C is for compression and S is for sparkplug. Covers all the latest severe duty diesel requirements. It's not cheap but I change it once a year and it still looks reasonably good at that time. You could order it today and it will be on your doorstep in a day or two. I'll try to send a link so you can check it out. AMSOIL Signature Series Max-Duty Synthetic Diesel Oil 5W-4 If you sign up as a preferred customer at the same time you can by AMSOIL at wholesale for a year. That's what I do. There's even a filter cross reference page if you want them to send a filter at the same time. Dutchy
RalphVa
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Just change it a little sooner than you would a diesel rated oil. Main difference (maybe only one) is diesel rated oils have more detergent to hold the blowby soot in suspension.
On our 240D Benz, I went one oil change on it with gasoline rated oil. Don't recall exactly why, but I did it on purpose.
Ralph
On our 240D Benz, I went one oil change on it with gasoline rated oil. Don't recall exactly why, but I did it on purpose.
Ralph
