Quick Picks - Best Engine Oils

Understanding Oil Viscosity - What Do the Numbers Mean?

Decoding 5W-30, 5W-20, 0W-20

Example: 5W-30

• First number (5W): Winter viscosity - how the oil flows in cold temps. Lower = better cold flow.
• W: Stands for "Winter"
• Second number (30): Operating viscosity at 100°C (212°F). Higher = thicker oil when hot.

0W-20 vs 5W-20 vs 5W-30 - Which Do You Need?

0W-20 (Thinnest)

Best for: Modern fuel-efficient engines (Honda, Toyota, Mazda, Ford EcoBoost)

• ✅ Maximum fuel economy (less friction)
• ✅ Best cold-start protection (flows instantly at -40°F)
• ✅ Required by many 2015+ vehicles
• ⚠️ Not suitable for older engines (can cause leaks)
• ⚠️ May burn off faster in hot climates

Common vehicles: Honda Civic/Accord, Toyota Camry/RAV4, Mazda CX-5, Ford F-150 EcoBoost

5W-20 (Medium-Thin)

Best for: Most modern cars and light trucks (2000+)

• ✅ Good fuel economy
• ✅ Good cold-start performance
• ✅ Most common specification for modern engines
• ✅ Works in most climates (-31°F to 100°F+)

Common vehicles: Ford F-150 (non-EcoBoost), Chevy Silverado 1500, Jeep Wrangler, Subaru Outback

5W-30 (Medium)

Best for: High-mileage vehicles, hot climates, towing/hauling

• ✅ Better protection under load (towing, hauling)
• ✅ Thicker oil film protects older/worn engines
• ✅ Better for hot climates (less evaporation)
• ✅ Universal fit (works in most engines)
• ⚠️ Slightly lower fuel economy vs 0W-20/5W-20

Common vehicles: Older cars (pre-2010), trucks that tow, high-mileage vehicles (100K+ miles)

CRITICAL: Always Use Your Vehicle's Recommended Viscosity

Check your owner's manual or oil cap sticker. Modern engines are designed for specific oil weights. Using thicker oil (e.g., 5W-30 when 0W-20 is specified) can:

• Reduce fuel economy by 1-2%
• Increase engine wear during cold starts
• Void warranty (if specified oil isn't used)

Using thinner oil can cause oil consumption, leaks, and lack of protection.

Need to find your vehicle's oil capacity? Search our oil capacity database.

Synthetic vs Synthetic Blend vs Conventional Oil

Full Synthetic Oil

Price: $25-50 per 5 quarts

• ✅ Best protection (extreme temps, towing, performance driving)
• ✅ Longer change intervals (10,000-15,000 miles vs 3,000-5,000)
• ✅ Better cold-start protection (flows at -40°F)
• ✅ Resists breakdown under high heat
• ✅ Cleaner engine (fewer deposits and sludge)
• ⚠️ More expensive upfront (but lasts 3X longer = lower cost per mile)

Recommended for: All modern cars (2010+), turbocharged engines, high-performance cars, towing/hauling

Synthetic Blend Oil

Price: $18-30 per 5 quarts

• ✅ Better than conventional, cheaper than full synthetic
• ✅ Good for high-mileage vehicles not ready for full synthetic
• ✅ Change interval: 5,000-7,500 miles
• ⚠️ Not as good protection as full synthetic
• ⚠️ Doesn't last as long

Recommended for: Budget-conscious drivers, older vehicles (1990s-2000s), light-duty use

Conventional Oil

Price: $15-25 per 5 quarts

• ✅ Cheapest option
• ✅ Adequate for low-mileage, gentle driving
• ⚠️ Change every 3,000-5,000 miles
• ⚠️ Poor cold-start protection
• ⚠️ Breaks down faster under heat/stress
• ⚠️ Forms sludge over time

Recommended for: Very old cars (pre-1990), lawnmowers, low-budget situations

The Math: Synthetic Actually Costs LESS

Result: Full synthetic saves $130 per 15,000 miles AND provides better engine protection.

Detailed Oil Reviews

Engine Oil FAQ

Can I mix different brands of synthetic oil?

Yes, as long as the viscosity matches (e.g., 5W-30 + 5W-30). All synthetic oils meeting the same API/ILSAC specs are chemically compatible. However, you'll dilute the premium additives, so avoid mixing if possible.

Can I switch from conventional to synthetic?

Yes, you can switch at any time. Modern synthetic oils are backward compatible. If your engine has 100K+ miles and has always used conventional, consider a high-mileage synthetic to avoid disturbing old deposits that may be "sealing" worn areas.

Will synthetic oil cause leaks in older engines?

Myth. Synthetic oil doesn't cause leaks - it just reveals existing leaks faster because it flows better. If seals are already worn, they'll eventually leak with any oil. High-mileage synthetic actually helps condition seals and reduce leaks.

How often should I change synthetic oil?

Most full synthetics are good for 10,000-15,000 miles or 1 year (whichever comes first). Check your owner's manual for manufacturer recommendations. Severe conditions (towing, racing, extreme heat/cold, stop-and-go traffic) may require more frequent changes.

What does "API" and "ILSAC" mean on oil bottles?

• API (American Petroleum Institute): SN, SP = current standards for gasoline engines. Higher letter = newer/better.
• ILSAC (International Lubricant Standardization and Approval Committee): GF-6A/GF-6B = latest standards for fuel economy and emissions.
• dexos: GM's proprietary specification (dexos1 Gen 2 for most GM vehicles).

Always use oil meeting your vehicle's required specs (listed in owner's manual).

What's the difference between "Extended Performance" and regular Mobil 1?

Mobil 1 Advanced (regular): 15,000 miles / 1 year protection. ~$28 per 5 quarts.

Mobil 1 Extended Performance: 20,000 miles / 1 year protection. ~$35 per 5 quarts.

Extended Performance has extra additives for longer intervals. Worth it if you drive 15K+ miles/year. Not worth it for typical drivers (10K miles/year).

Should I use 0W-20 or 5W-30 in my high-mileage car?

Stick with your owner's manual recommendation. If your manual specifies 0W-20 but your engine is burning oil or has 150K+ miles, you can switch to 5W-20 or 5W-30 for thicker oil film protection. Consult a mechanic if unsure.