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Knowledge that protects engines

Practical, independent explanations of oil specifications, viscosity, lubrication, engine protection, and automotive fluids.

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Unbranded automatic transmission components and measuring container with transmission fluid on a workbench.
Specifications Explained

Ford MERCON ULV, LV and SP Transmission Fluids Explained

MERCON ULV, MERCON LV and MERCON SP are separate Ford automatic-transmission-fluid specifications, not a simple progression of interchangeable low-viscosity oils. Learn how to read the associated Ford material codes, why transmission design controls the choice, and how to verify a replacement fluid.

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Specifications Explained Unbranded engine oil containers beside a modern gasoline engine bay.

Chrysler MS-6395 Engine-Oil Requirement Explained

Chrysler MS-6395 is a manufacturer material standard used for many Chrysler, Dodge, Jeep and Ram gasoline engines. It is not a viscosity grade or a blanket rule for every Stellantis vehicle, so the current manual’s exact oil grade and API requirement still control.

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Specifications Explained Unbranded automatic transmission fluid bottles beside a modern transmission valve body.

DEXRON VI, HP and ULV Transmission Fluids Explained

DEXRON VI, DEXRON-HP and DEXRON ULV are distinct GM automatic-transmission-fluid requirements, not interchangeable names for “synthetic ATF.” Learn why the transmission, not the fluid’s color or marketing description, determines which one is correct.

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Specifications Explained Unbranded modern light-duty diesel engine prepared for an engine-oil service.

GM dexosD Diesel Engine-Oil Requirement Explained

GM dexosD is a licensed diesel engine-oil requirement, not a substitute name for 0W-20 or 5W-30. Learn how it replaced dexos2 for light-duty diesel use, why the exact viscosity still matters, and how to verify a genuinely licensed oil.

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Specifications Explained Generic two-stroke engine components and an unlabeled oil mixing container on a workshop bench.

JASO FB, FC and FD Two-Stroke Oil Standards Explained

JASO FB, FC and FD describe performance levels for gasoline two-stroke oil, with FC focused on reduced smoke and FD adding stronger high-temperature cleanliness. Learn why the grade matters, why it does not set the fuel-mix ratio, and why TC-W3 marine oil is a separate requirement.

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Specifications Explained Unbranded engine-oil samples and viscosity-testing equipment beside a modern gasoline-engine cutaway.

JASO GLV-1 and GLV-2 Engine-Oil Standards Explained

JASO GLV-1 and GLV-2 are fuel-economy-focused gasoline engine-oil classifications, but they cover different viscosity ranges and are not substitutes for a vehicle maker’s exact requirement. Learn how GLV-1, GLV-2A and GLV-2B relate to 0W-8, 0W-12, 0W-16 and 0W-20 oils.

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Specifications Explained Modern four-cylinder engine bay prepared for an engine-oil service with unbranded tools and container.

Volvo VCC C6SP and RBS0-2AE Engine-Oil Specifications Explained

Volvo’s VCC C6SP and VCC RBS0-2AE labels are engine-oil requirements, not merely alternative names for 0W-20. Learn what the codes mean, how ACEA C6 and API SP fit into the picture, and why the current manual for the exact vehicle remains the deciding document.

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Specifications Explained Unbranded engine-oil bottles and a clean engine component illustrating Porsche oil approval selection.

Porsche A40, C20, C30, C40 and C40 GT Engine-Oil Approvals Explained

Porsche oil codes identify manufacturer approvals, not just oil thickness. This guide explains the practical meaning of A40, C20, C30, C40 and C40 GT, why two 0W-40 oils may still be unsuitable substitutes, and how to verify the correct approved product for a Porsche engine.

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Specifications Explained Unbranded engine oil containers beside an engine oil filler cap in a clean workshop.

Ford WSS Engine-Oil Specifications Explained: 945-B1, 961-A1, 962-A1 and 971-A1

Ford’s WSS-M2C engine-oil codes are vehicle material specifications, not interchangeable shorthand for viscosity. This guide explains how to read common 5W-20, 0W-20 and 5W-30 Ford WSS requirements, why API or ILSAC marks still matter, and how to choose oil without assuming that a newer-looking code fits every Ford or Lincoln engine.

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Specifications Explained Unbranded engine-oil containers beside a modern passenger-car engine bay for an article about Mercedes-Benz oil approvals.

Mercedes-Benz MB 229 Oil Approvals Explained: 229.5, 229.51, 229.52, 229.71 and 229.72

Mercedes-Benz oil requirements are defined by approval numbers, not viscosity alone. This guide explains the practical differences between MB 229.5, 229.51, 229.52, 229.71 and 229.72, what “Low SPAsh” means, and how to verify the correct oil for a specific Mercedes-Benz passenger car or van.

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