2018 Kia Optima Oil Type & Capacity
The 2018 Kia Optima uses 0W-30 or 10W-40 or 5W-30 oil, with a capacity of about 4.3-5.6 quarts depending on the engine.
Key takeaways
- Oil: 0W-30/10W-40/5W-30, about 5.6 quarts with a filter change.
- Grade and capacity vary by engine - match your exact engine.
- Change the oil filter every time you change the oil.
| Engine | Viscosity | Capacity |
|---|---|---|
| 1.6 CRDi DPF | 0W-30 | 4.3 qt / 4.1 L |
| 1.6 CRDi | 10W-40 | 4.3 qt / 4.1 L |
| 1.6 T-GDI | 5W-30 | 4.8 qt / 4.5 L |
| 1.7 CRDi DPF | 0W-30 | 5.6 qt / 5.3 L |
| 1.7 CRDi | 10W-40 | 5.6 qt / 5.3 L |
| 2.0 CVVL | 5W-30 | 4.5 qt / 4.3 L |
Capacities are with an oil-filter change. Confirm on the dipstick after refilling.
Oil & filter for the 2018 Kia Optima
You need 0W-30 oil (5.6 quarts with a filter change). Buy the oil and a filter together; a DIY oil change takes about 30 minutes, or any shop can do it.
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Shop 0W-30 oil + filterHow much oil should you buy?
Oil is sold in 5-quart jugs and single-quart bottles, and almost no engine takes a round number, so a single jug is usually either not enough or more than you need. Here is the plan for each engine in this vehicle:
| Engine | Needs | Buy | Left over |
|---|---|---|---|
| 1.6 CRDi DPF | 4.3 qt (4.1 L) | 1 × 5 qt jug | 0.7 qt |
| 1.6 CRDi | 4.3 qt (4.1 L) | 1 × 5 qt jug | 0.7 qt |
| 1.6 T-GDI | 4.8 qt (4.5 L) | 1 × 5 qt jug | 0.2 qt |
| 1.7 CRDi DPF | 5.6 qt (5.3 L) | 1 × 5 qt jug + 1 × 1 qt | 0.4 qt |
| 1.7 CRDi | 5.6 qt (5.3 L) | 1 × 5 qt jug + 1 × 1 qt | 0.4 qt |
| 2.0 CVVL | 4.5 qt (4.3 L) | 1 × 5 qt jug | 0.5 qt |
At 4.3 quarts this is a small-capacity engine, below the 5.5-quart median across the vehicles we hold. It is cheap to service, and it is also less forgiving of running low, because there is less oil to lose. These figures include a filter change. If you are only draining the sump and reusing the filter you will need slightly less, so add most of it, run the engine, and finish on the dipstick rather than pouring the whole amount in.
Which engine do you have?
The 2018 Kia Optima was sold with 6 different engines, and they differ in both directions: capacity runs from 4.3 to 5.6 quarts and they do not all take the same grade. Getting this wrong means the wrong oil, not just the wrong amount. Check the engine badge or the label under the hood before you buy, and confirm on the dipstick after refilling rather than trusting the quart count alone.
What 0W-30 actually means
The 0W is the cold rating - the W stands for winter, and a lower number means the oil stays thin enough to pump on a freezing start, which is when most engine wear happens. The 30 is how thick the oil is once the engine is hot and at operating temperature. So 0W-30 flows like a 0-weight oil on a cold morning and protects like a 30-weight once warmed up.
0W-30 is a less common grade, at 4.1% of the engines we hold specs for versus 51.4% for 5W-30. It is still a stocked size, but do not assume the shelf default is right for this car.
Full synthetic is worth it here, and at this point it is mostly what is on the shelf anyway. What matters more than the brand is that the bottle carries the current API service rating and the grade above. See how this grade compares across the US fleet.
Can you use a different weight than 0W-30 / 10W-40 / 5W-30?
Use the specified grade. A heavier oil than 0W-30 does not "protect better" - it flows more slowly when the engine is cold, which is exactly when wear happens. A lighter one may not hold up at operating temperature. The grade on this page is what the engine was designed around.
The exception most people are thinking of is an older, high-mileage engine that has started using oil between changes. Going one grade heavier there is a real, if temporary, way to slow that down. It is a way of managing wear that has already happened, not a way of preventing it, and it is not a reason to deviate on a healthy engine.
When to change it
On full synthetic, most vehicles land in the 7,500-mile range under normal use and closer to 5,000 under severe use. Severe is not unusual driving - it means short trips that never fully warm the engine, stop-and-go traffic, towing, dust, or extreme heat or cold. If your car is mostly doing school runs and errands, you are in the severe column, which surprises people. If your car has an oil-life monitor, trust it over any fixed number, because it is watching how the engine is actually being used.
These are typical intervals for guidance. Your owner's manual is the authority for your exact vehicle - some engines, oils, and fluids have longer or shorter intervals.
Frequently asked
How much oil does a 2018 Kia Optima take?
It depends on the engine: 1.6 CRDi DPF takes 4.3 qt; 1.6 CRDi takes 4.3 qt; 1.6 T-GDI takes 4.8 qt; 1.7 CRDi DPF takes 5.6 qt; 1.7 CRDi takes 5.6 qt; 2.0 CVVL takes 4.5 qt.
What kind of oil does a 2018 Kia Optima use?
0W-30 or 10W-40 or 5W-30 full-synthetic motor oil.
How many jugs of oil do I need for a 2018 Kia Optima?
It depends on the engine. For the 1.6 CRDi DPF: Buy 1 × 5-quart jug (5 quarts). That covers the 4.3 quarts this engine needs and leaves about 0.7 of a quart spare for topping up.
Can I use a thicker oil instead of 0W-30?
Use the specified grade. A heavier oil than 0W-30 does not "protect better" - it flows more slowly when the engine is cold, which is exactly when wear happens. A lighter one may not hold up at operating temperature. The grade on this page is what the engine was designed around.
Is 0W-30 a common oil grade?
0W-30 is a less common grade, at 4.1% of the engines we hold specs for versus 51.4% for 5W-30. It is still a stocked size, but do not assume the shelf default is right for this car.
Do all 2018 Kia Optima engines take the same amount of oil?
No. Capacity ranges from 4.3 to 5.6 quarts depending on which engine the car has, and the grade differs too. Match your exact engine before buying.
How often should a 2018 Kia Optima have an oil change?
On full synthetic, plan on roughly 7,500 miles under normal driving and about 5,000 under severe use - short trips, stop-and-go, towing, dust, or extreme temperatures. If the car has an oil-life monitor, follow it rather than a fixed mileage, because it reacts to how the car is actually driven.
See where this sits in our study of the most common engine oil viscosities in the US.