What Type of Oil Does a Generac Generator Use

Your Generac generator is only as reliable as the oil you put in it. Using the right oil keeps the engine running smoothly, prevents wear, and helps the generator last longer. But not all oil is the same, and picking the wrong one can lead to performance issues.

Generac recommends specific oil types based on temperature and engine needs, so it’s important to choose wisely. In this guide, we’ll break down what type of oil your Generac uses, when to change it, and how to keep your generator in top shape. If you’d rather leave the maintenance to the pros, Schedule an Estimate and we’ll make sure your generator is serviced properly.

Recommended Oil for Generac Generators

Using the right oil keeps your Generac generator running efficiently and protects the engine from wear. Generac has specific recommendations based on temperature and engine type.

1. Generac’s Recommended Oil Type

Generac recommends SAE 10W-30 for most of its generators. This is a good all-purpose oil that works well in a range of temperatures.

2. Cold Weather Conditions

If you live in an area where temperatures drop below 20°F (-7°C), SAE 5W-30 synthetic oil is a better choice. It flows better in the cold, reducing strain on the engine during startup.

3. Extreme Heat Conditions

For areas where temperatures regularly exceed 90°F (32°C), SAE 30 oil is sometimes recommended for better performance under heavy load. However, SAE 10W-30 or SAE 5W-30 synthetic still work fine in most cases.

4. Generac-Branded Oil vs. Other Brands

Generac sells its own oil, but any high-quality, API SN-certified oil that matches the recommended viscosity will do the job. Brands like Mobil 1, Shell Rotella, and Valvoline meet the necessary standards.

The key is to match the oil to your climate and follow the manufacturer’s guidelines. Keeping up with regular oil changes will keep your generator performing when you need it most.

Synthetic vs. Conventional Oil

Choosing between synthetic and conventional oil for your Generac generator comes down to performance and longevity. Both will keep the engine running, but synthetic oil has some advantages.

1. Synthetic Oil Lasts Longer

Synthetic oil resists breakdown better than conventional oil. It holds up under high heat and cold temperatures, meaning you can go longer between oil changes.

2. Better Protection in Extreme Temperatures

If you live somewhere with very cold winters or hot summers, synthetic oil is the better choice. It flows better in freezing temps and doesn’t thin out as much in extreme heat.

3. Conventional Oil is Cheaper

Conventional oil costs less, but it breaks down faster and doesn’t provide the same level of protection. If you’re running your generator often or in harsh conditions, synthetic is worth the extra cost.

4. Generac’s Recommendation

Generac allows both types, but they specifically recommend SAE 5W-30 synthetic oil for best performance. It’s especially useful in cold weather and for generators that run for long periods.

Both oils work, but if you want better engine protection and longer intervals between changes, synthetic is the way to go.

How Temperature Affects Oil Choice

The oil you use in your Generac generator isn’t just about brand—it’s about how it handles the temperature where you live. The wrong oil in the wrong conditions can cause poor performance or even damage over time.

1. Cold Weather (Below 20°F / -7°C)

If temperatures drop below freezing, SAE 5W-30 synthetic oil is the best choice. It stays thin enough to keep the engine lubricated at startup, which is when most wear happens. Thicker oils struggle in the cold and can make it harder for the generator to turn over.

2. Moderate Climates (Between 20°F and 90°F / -7°C to 32°C)

For most areas, SAE 10W-30 is a solid choice. It’s a good middle ground that works in both warm and cool weather without breaking down too fast.

3. Hot Weather (Above 90°F / 32°C)

In extreme heat, SAE 30 oil can be used, though SAE 10W-30 synthetic is usually still recommended. Synthetic oil holds up better under heavy loads and high temperatures without thinning out too much.

4. Why It Matters

Oil that’s too thick in the cold can make it harder for your generator to start. Oil that’s too thin in the heat won’t protect the engine as well. Matching the right oil to your climate keeps your generator running smoothly and extends its life.

Checking your owner’s manual is always a good idea, but if you’re in an area with extreme temperatures, synthetic oil is usually the safest bet.

How Often to Change the Oil

Keeping up with oil changes is one of the most important things you can do to keep your Generac generator running strong. Ignoring it leads to engine wear, poor performance, and even failure when you need power the most.

1. First Oil Change

Right after installation, change the oil at 25 hours of runtime. This gets rid of any metal shavings or debris from the engine break-in period.

2. Regular Oil Change Schedule

• After the first change, every 100-200 hours is standard for most Generac standby generators.
• If your generator runs frequently or during long outages, check the oil level more often and change it sooner if needed.

3. Signs It’s Time for a Change

• Oil looks dark and dirty instead of a clean amber color.
• You notice a burnt smell when checking the dipstick.
• The generator sounds louder or rougher than usual.

4. Extreme Conditions Require More Frequent Changes

• Cold weather thickens the oil, making it work harder.
• Hot climates can cause oil to break down faster.
• Heavy generator use during extended power outages means more wear, so oil changes should happen sooner.

5. Don’t Forget the Filter

Every other oil change, swap out the oil filter too. A clogged filter means dirty oil circulates through the engine, cutting its lifespan.

Stay on top of oil changes, and your generator will be ready when you need it. Skipping them only leads to bigger problems down the road.

Regular oil changes keep your Generac generator running smoothly and ready for the next power outage. If you want to make sure your generator is properly maintained without the hassle, Contact Us for expert service. We’ll handle the oil changes, filters, and everything else to keep your generator in top shape.