The 2021 Ram 1500 with the 5.7-liter HEMI V8 uses full synthetic motor oil that meets Chrysler MS-6395, with a default viscosity of 5W-20 and an oil capacity of about 7 quarts (6.6 liters) including the filter. In hot climates or under heavy towing duties, 5W-30 may be used if endorsed by the owner's manual or a RAM service advisor.
Oil type and viscosity
The 5.7 HEMI is designed to run on a full synthetic oil that meets Chrysler MS‑6395. The standard viscosity for most conditions is 5W-20, which provides good cold-start protection and engine cleanliness across a wide temperature range. In very hot climates or when towing heavy loads, 5W‑30 is an acceptable alternative if allowed by the manual or dealer guidance.
The following options reflect the official guidance and practical usage for this engine.
- 5W-20 synthetic motor oil that meets Chrysler MS-6395 (API SP or better) — default recommended viscosity.
- 5W-30 synthetic motor oil that meets Chrysler MS-6395 — acceptable in hot climates or when the manual indicates it is appropriate.
- Oil capacity: approximately 7 quarts (6.6 L) with a filter change.
When choosing oil, use a high-quality synthetic oil from a reputable brand and confirm that it carries the MS-6395 specification on the bottle.
Capacity and maintenance notes
Oil capacity for the 5.7 HEMI in the 2021 Ram 1500 is about 7 quarts with the filter. Always replace the filter during an oil change and ensure the oil level is within the proper range on the dipstick after filling. For change intervals, refer to the owner's manual or your dealership’s maintenance schedule, as intervals vary with driving conditions and oil brand. Synthetic oils can extend intervals, but conditions such as frequent short trips, extreme temperatures, or heavy towing can shorten them.
How to confirm the right oil for your vehicle
To be certain you’re using the correct oil for your specific truck, check the owner’s manual, the oil fill cap, and the engine bay label. The cap and label will indicate the required viscosity (5W-20) and the MS-6395 specification or the latest specification endorsed by Mopar. If you’re unsure, consult a RAM service advisor or refer to RAM’s official maintenance documentation.
Manual specifications
Always verify the exact spec on your vehicle’s documentation and on the engine bay sticker. The manual will confirm current recommendations, including whether 5W-30 is permitted under certain conditions for your particular truck and region.
Summary
The 2021 Ram 1500 5.7 HEMI takes full synthetic 5W-20 oil that meets Chrysler MS-6395, with an oil capacity of about 7 quarts including the filter. In hot climates or during heavy towing, 5W-30 can be used if supported by the manual or dealer guidance. Always verify the exact specification in your owner's manual and follow the recommended maintenance intervals for your driving conditions.