5W-30 vs 10W-30 Engine Oil
Reviewed by GarageDex editorial
5W-30 and 10W-30 are the same thickness when hot (both 30); 5W-30 flows better when cold. 5W-30 is the better all-season choice for most modern engines; 10W-30 suits hot climates and older engines.
| 5W-30 | 10W-30 | |
|---|---|---|
| Hot thickness | 30 (same) | 30 (same) |
| Cold-start flow | Better (5W) | Worse (10W) |
| Cold climates | Preferred | Not ideal |
| Typical use | Most modern engines | Older engines, hot climates, some trucks |
With the same 30 hot rating, both protect equally once warm. The difference is winter start-up: 5W-30 flows at a lower temperature than 10W-30, so it reaches bearings faster in the cold.
10W-30 is still specified for some older engines and high-temperature use. In a modern engine that calls for 5W-30, there is no benefit to 10W-30 and a real downside in cold weather.
Which should you use?
For most drivers, 5W-30. Use 10W-30 only where the manual specifies it or in consistently hot climates with an older engine.
Frequently asked
Is 10W-30 thicker than 5W-30?
Only when cold. 10W-30 is more resistant to flow at low temperatures; once at operating temperature both are a 30-weight and behave the same.
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