Owners of a 2018 Jeep Grand Cherokee often wonder about the specific maintenance details, and one of the most fundamental questions concerns the oil capacity. Understanding the exact amount of lubricant required ensures the engine operates at peak efficiency and longevity. This specific measurement varies slightly depending on the trim level and the installed engine, but there is a standard range that applies to the model year.
Factory Specifications by Engine Type
The 2018 model year offered a variety of powertrains, from the efficient four-cylinder to the robust V6 and available V8. Consequently, the oil capacity is not a one-size-fits-all number. To determine the exact amount for your vehicle, you must identify which engine is installed under the hood. The larger the displacement, the greater the volume of oil required to properly lubricate the moving components.
3.6L Pentastar V6 and 5.7L HEMI V8
For the base models equipped with the 3.6L Pentastar V6, the total oil capacity is generally around 6.4 quarts. This figure assumes a standard oil filter replacement and a dry fill procedure. If your Grand Cherokee features the more powerful 5.7L HEMI V8, the requirement increases significantly to approximately 6.8 quarts. This higher volume is necessary to adequately cool and protect the additional cylinders and larger bearing surfaces found in the V8 configuration.
3.0L EcoDiesel I6
Jeep also offered a turbocharged 3.0L EcoDiesel inline-six cylinder for those seeking towing capability and fuel efficiency combined. This diesel engine has a unique requirement and holds roughly 1.2 quarts more than the V6. The total capacity for the EcoDiesel variant is approximately 7.5 quarts. Due to the complexity of the diesel particulate filter and emissions system, using the correct weight of 5W-40 oil is critical for proper performance.
Why Capacity Matters
Simply pouring in the exact volume specified for your 2018 Grand Cherokee is about more than just filling a void. Overfilling the crankcase can lead to increased pressure within the engine, potentially causing oil leaks or damaging the seals. Conversely, underfilling results in inadequate lubrication, which causes friction, heat buildup, and premature wear on critical internal parts.
The Filter Factor
When performing an oil change, the stated capacity assumes that a new, standard oil filter is being installed. These factory filters have a small internal volume that absorbs a portion of the new oil. If you are replacing a very old, dirty filter or switching to a high-performance aftermarket filter with a larger media, the filter may hold a different amount of oil. Technicians often account for this by adding a little extra or checking the dipstick after the refill to ensure the level is spot on.
Checking Your Specific Level
Even if you are following a generic guide, the most accurate method to verify the oil level is the dipstick. After pouring the oil, start the engine and let it run for a few minutes, then turn it off. Wait a few minutes for the oil to drain back into the pan. Pull out the dipstick, wipe it clean, reinsert it fully, and pull it out again. The oil level should be between the "Add" and "Full" marks. Do this check regularly to catch any potential leaks or consumption early.
Synthetic vs. Conventional Fluids
The type of oil you choose—synthetic blend or full synthetic—does not usually change the total capacity of the engine. However, synthetic oils often perform better at maintaining viscosity across temperature ranges, which is beneficial for the severe driving conditions the Jeep Grand Cherokee might encounter. Using a high-quality oil that meets the Jeep manufacturer's specifications will protect your investment regardless of the quart amount you put in.
