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Amber conventional GTX engine oil in a one-quart bottle

Castrol

Castrol GTX 10W-40 Engine Oil 1 Qt 06146

SKU CH-6B8A-QATM8

Conventional 10W-40 engine oil for gasoline engines, API SN/SJ/SL/SM rated

  • Protects gasoline engines with API SN/SJ/SL/SM certification
  • Flows reliably in cold starts down to -27.4 °F pour point
  • Maintains film strength at high heat with 392 °F flash point
  • Delivers stable viscosity across temperatures with 133 viscosity index
  • Ready for top-ups in convenient 1 qt bottle

Conventional GTX Engine Oil

Castrol GTX 10W-40 is a conventional petroleum-based engine oil formulated for gasoline engines. The 1-quart bottle meets API SN, SJ, SL, and SM service classifications. It suits drivers who follow manufacturer specifications for this viscosity grade.

Thermal stability and cold flow

The oil has a flash point of 392 degrees F and a pour point of -27.4 degrees F. Viscosity measures 108.3 cSt at 40 degrees C and 14.3 cSt at 100 degrees C. A viscosity index of 133 indicates stable performance across temperature ranges.

Single-quart top-up format

The one-quart bottle is designed for oil top-ups between changes rather than a full drain and fill. It fits standard engine filler necks without special tools. Buyers needing a complete oil change volume or synthetic formulation should select a different product.

Highlights

  • Protects gasoline engines with API SN/SJ/SL/SM certification
  • Flows reliably in cold starts down to -27.4 °F pour point
  • Maintains film strength at high heat with 392 °F flash point
  • Delivers stable viscosity across temperatures with 133 viscosity index
  • Ready for top-ups in convenient 1 qt bottle

Specifications

BrandCASTROL

Questions about this item

How do I install this 1 qt bottle of Castrol GTX 10W-40 and what step do people get wrong?

Warm the engine, drain the old oil, replace the filter, then pour in the fresh 10W-40; the step often missed is checking the dipstick after the engine runs briefly to confirm the correct fill level.

What maintenance or replacement will this engine oil need later?

Replace the oil and filter at the mileage or time interval specified by the vehicle manufacturer; the 10W-40 conventional formulation does not extend that interval.

What limit shows up first under sustained use with this 10W-40 oil?

Conventional base stock breaks down faster than synthetic, so viscosity stability at the 392 °F flash point and oxidation resistance become the limiting factors during prolonged high-temperature operation.

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