This should be fine, although in very cold weather you might have a little more difficulty starting the engine because 15W 40 oil is thicker than 10W 40.
The main difference between 10W-40 oil and 15W-40 oil is that 15W-40 oil has a higher viscosity than 10W-40 oil. 10W-40 oil allows the engine to run freely.
You can. I like 10w40 best.
15W-40 15W-40
15w 40 engine oil can be used for all temperatures down to -15 deg centergrade !
15w 40 is recommended for this size engine. 10w 40 will suffice if no 15w is available.
15w 40 shell HX5
15w 40
Lucas 15W-40
8 quarts 15w-40
15W-40
Yes, you can switch from 15W-40 to 10W-30 oil, but it's important to consider your vehicle's requirements and the operating conditions. The numbers indicate the oil's viscosity; the first number represents its flow at low temperatures, while the second indicates its flow at high temperatures. If your engine is designed to use 10W-30, this switch may be beneficial for fuel efficiency and cold starts. However, if your engine requires 15W-40 for better high-temperature protection, using 10W-30 might not provide adequate lubrication, especially in hotter climates or under heavy loads. Always check your owner’s manual for the manufacturer’s recommendations.
If you use the same weight as The original oil, for example now the engine uses 15W-40, and you do an oil change, filling it with the same specs 15W-40 oil that's no problem for the engine.