5w-40 has a broader operating range than 15w-40. Unless you're penny pinching or you're misinformed about synthetic oils, it's stupid to pick the 15w-40 option. There is a single benefit to 15w-40 oils though, they will maintain their 40 weight operating viscosity longer than an oil that starts at 5w.

Is 5w40 thinner than 15w40?

In general, in a given engine at operating temperature a 5W-40 and a 15W-40 have the same viscosity; one will not be “thinner” or have a lower viscosity than the other. Both will have a viscosity of a 40 grade. That cannot be said for both oils during the dead of winter.

What is the difference between 5W and 15W oil?

A 5W viscosity grade requires the lubricant to flow properly at lower temperatures than, for example, a 15W viscosity grade, so it is expected to be used at lower starting temperatures.

Can you mix 5w40 with 15w40?

Mixing a dino with a syn, a syn with a dino, a 5W-40 with a 15W-40, and so on is fine. You aren't going to get an additive clash, the different base stock of x brand of oil won't sponteously combust with the other x brand of oil that you are blending it with and make your engine throw a rod.

When should I use 15w40 oil?

ADVANTAGE 15W-40 HEAVY DUTY DIESEL ENGINE OIL can be used with complete success in over-the-road diesel trucks, off-highway diesel equipment, farm tractors, and passenger cars and light trucks with diesel, turbo-charged diesel engines, or gasoline engines and is backward compatible with previous API Oil Categories.

5w-40 vs 15w-40

Is 5W40 good for diesel engines?

One engine oil for mixed fleet operations

Mobil 1 Turbo Diesel Truck 5W-40 engine oil is recommended for use in all super-high-performance diesel applications, including modern low-emission engine designs with Exhaust Gas Recirculation (EGR).

Is 15W40 good for gas engines?

Mobil Gas Engine Oil 15W-40 is a premium fleet engine oil specifically formulated to provide reliable protection for trucks and buses using Compressed Natural Gas (CNG) or Liquefied Natural Gas (LNG). Mobil Gas Engine Oil 15W-40 is formulated from high quality base stocks and a balanced additive system.

Is all 15w40 oil the same?

No. Oils carry a certification and must be selected to meet or exceed the recommendations in your engine manual. Oil standards are normally backwards compatible, but the base oils are different.

Can you mix different viscosity oils?

yes you can mix same brand and type oils with different viscosity and it will be fine as long as you don't mix them 50/50. If you mix 200 ml of oil with the rest of oil needed for your engine you will be totally fine.

Can I use 5W40 in my Duramax?

Our answer: Yes, you can certainly use 5W-40 in winter (and summer) in your Duramax. While 15W-40 is suggested as the predominant viscosity for your engine, GM does recommend 5W-40 for temps below -18°C (0°F).

Is 5w40 good for summer?

5w30 oil is designed to operate at temperatures as low as -25°C, but is also a great choice for warmer climates that reach up to 25°C.

Is 15w-40 good for cold weather?

Even without a block heater, our recommendation is to stay with 15W40. The oils are very well formulated and flow at very low temperatures.

Which is better 5w30 or 15W40?

15w40 is usually used in diesel engines and has a much different additives profile. 5w30 is usually used in gasoline engines. Diesel oil is designed with high antiwear additives such a ZDDP.

Can we use 15W-40 instead of 5w40?

YES. Lowering the first number gives you much faster oil circulation on every startup, and especially in the cold. So you engine will have lower wear on every start-up. And since it flattens the viscosity curve, in hotter areas, like turbos, a 5W-40 will have more viscosity than a 15W-40.

What 15W-40 means?

What does 15W-40 mean? 15W-40 viscosity grade means it flows like a 15 weight oil from start up in Winter, but provides the protection of a 40 weight once the engine reaches full operating temperature.

Can we use 15W-40 instead of 5W30?

No, you won't blow a head gasket, but 15W40 is too heavy an oil to use where 5W30 is required. Besides, most 15W40 oils are gor diesel engines.

Is it OK to top up engine oil with different brand?

You can add any engine oil as long as it has the right specifications — preferably with an official approval of the OEM (Original Equipment Manufacturer). Not the brand, but the specification and viscosity indicated in your car's manual are your reference for using the right oil.

Will mixing oils hurt your car?

Yes. It won't harm your engine to mix, for example, Quaker State^® motor oil with Pennzoil, as long as the oil you use is the weight (or viscosity) recommended in your vehicle owner's manual.

Is it OK to mix synthetic oil brands?

Yes, you can safely mix one brand of oil (e.g. Mobil 1) with a different brand (e.g. AMSOIL) or conventional oil with synthetic oil (in fact, that's what a synthetic blend is). Most synthetics today are fully compatible with conventional oils and can safely be mixed.

Is 15W-40 fully synthetic?

Mobil Delvac™ Extreme 15W-40 is a synthetic, high-performance diesel engine oil that helps extend engine life while providing long drain capability for modern diesel engines operating in extreme conditions.

Is 15W-40 oil for diesel?

15W-40 is a very common viscosity grade for diesel engine oil. GTX Diesel is a 15W-40 diesel engine oil formulated to help extend engine life.

What is the best oil to use in a diesel engine?

If you're looking for the best oil for your diesel engine, you can't go wrong with synthetic oil. Synthetic oil is designed to withstand extreme temperatures and conditions, making it ideal for use in diesel engines. It also provides superior protection against wear and tear, helping to extend the life of your engine.

Which is better 10W-30 or 15W-40?

High quality 10W-30 oils can perform as well, and better than industry-standard 15W-40 oils. The stated viscosity of a HDEO does not represent an exact viscosity, but rather a viscosity within a range on the SAE viscosity scale.

What happens if you put diesel oil in a gas engine?

Instead, it will clog up the fuel filter. And whatever amount of diesel that then makes its way to the engine will clog the fuel injectors, making them inoperable. This will result in the engine gumming up and seizing.

Which is thicker 15W-40 or 10w30?

Because 10W-30 is thinner than 15W-40 oil, its film strength can be weaker and it can be more prone to oxidation. Therefore, high quality additives are needed to compensate for those weaknesses in order for a 10W-30 engine oil to protect as well and last as long as a 15W-40.