You can mix 10W & 30W to get 20W or you can mix 5W20 & 10W40, but you do not want to mix 10w & 10W30. In other words, it's OK to mix straight weights or multigrades but not straight weights & multigrades..
Regarding this, can you add 10w30 to 5w20?
Whether the oil is thicker or extra thinner, it specifies the type of engine it is suitable for. There are hundreds of oils but 10w30 and 5w20 are the most common of all. The 10w30 type is the thicker one and 5w20 is the thinner.
Subsequently, question is, can you mix 5w30 and 5w20? 5W-30 and 5W-20 motor oil both feature the same winter rating. This means that both grades exhibit the same viscosity under cold conditions. You also risk engine damage when using 5W-30 instead of 5W-20, as the internal engine components are specifically designed to be used with 5W-20 motor oil.
Subsequently, question is, can you mix 5w30 and 10w30?
Keep in mind oils do not mix if you have 5w30 and add 10w30 it won't give you a blens both oils will stay seperate so you will have a few quarts 5w30 and a quart 10w30 they never mix.
Can u mix different weight oils?
The good news is that mixing different types of oil it will not harm your engine in any way in the short run. Most synthetic and semi-synthetic engine oils are based on regular oil and are compatible. Now, as far as different grades are concerned, mixing between them isn't something that will damage your engine either.
Related Question Answers
What happens if you use the wrong oil?
The brand of motor oil matters little, but its viscosity grade (10W-30, for example) is important. Using the wrong oil can lead to reduced lubrication and shorter engine life. If the manual says to use synthetic oil, do so.Will 5w20 hurt a 5w30 engine?
Swapping 5w20 for 5w30 would *not* be a good idea. If the manufacturer of your car doesn't spec 5W20 oil then you shouldn't use it. The oil will be too thin (the smaller the number the "thinner" the oil) to provide the needed protection for your engine.Does mixing engine oil matter?
Mixing Motor OilAccording to Mobil Oil, it should be fine to mix oils. Many oils are a blend of natural and synthetic oils. So, if you are low on oil, don't be afraid to add a quart or two of synthetic oil if you are using regular oil or even regular oil if you are using a synthetic.What happens if you use 10w30 instead of 5w30?
5W30 motor oil means that the oil has a thinner consistency in cold weather and will protect your engine at lower temperatures. Also, 10W30 means the oil will be a little thicker at same lower temperatures, and will then protect the engine the same as 5W30 at higher temperatures.Which oil is thicker 5w30 or 10w30?
5w30 is used for light-duty engines while 10w30 is used for engines which carry heavier loads. 10w30 provides sealing action in the engine due to the fact that it is thicker than 5w30 engine oil. Thinner at lower temperatures. Thicker at lower temperatures.Is 5w20 better than 10w30?
For example, the 5W20 is better suited to cold regions where the viscosity required of the oil must be enough to get the engine moving during very cold periods while the 10w30 is better suited to hot conditions where heat doesn't have a significant effect on the viscosity.Can I use 10w 40 instead of 5w20?
In a 5W20 engine. You could use a 0W20 oil (I use 0W20 oil) in cold weather and it would be Ok by Ford. (they will not say it is good, but they will still honor the warranty..) But 10W40 is way off, and I bet they would be not so happy over any engine problems if they found 10W40 in a failed engine.What do oil weight numbers mean?
Oil weight is a term used to describe the viscosity of an oil, which means how well it flows at a specific temperature. This means a 30 weight oil flows more quickly than 50 weight oil, but doesn't offer quite the same level of protection at higher operating temperatures or in stressful conditions.Will it hurt to put 10w30 in a 5w30 engine?
yes 10w30 should meet the same standards as 5w30 just will not go as low temp.What happens when you mix oil viscosities?
Different oil viscosities will not separate or react negatively to each other because the base oil is molecularly the same. It's the different oil additive systems between brands that shouldn't be mixed - if you're concerned about the oil performing exactly how it was designed.Can you mix synthetic oil with regular oil?
The simple answer: Yes. There is no danger mixing synthetic and conventional motor oil; however, conventional oil will detract from the superior performance of synthetic oil and reduce its benefits. So, yes, you can safely mix synthetic and conventional oil.Can you mix 5w with 10w oil?
No you can't! The Hydrocabons molecular structure is different, the 5W will seperate from the 10W.Can you mix oil viscosities?
Chris says, “Yes it is possible to alter engine oil viscosity by mixing two different viscosity grade engine oils. Also, with respect to the winter grade, mixing oils with disparate winter grades will result in some undefined combination winter grade.Can I mix SAE 30 with 5w30?
You are correct that adding 1qt SAE 30 to 3qt SAE 5w-30 will increase viscosity of the 5w-30 at ALL temps.Can you mix 10w30 and 10w40?
Changing from 10W30 to 10W40 will not do any effect on your engine if you choose right one for the right season. Its totally safe you can go for it. The difference between 10w30 and 10w40 is the thickness of the oil at high temperatures, at which 10w40 is thicker than 10w30.Can you mix Mobil 1 Extended Performance?
Mobil 1 is fully compatible with conventional motor oils, semi-synthetic motor oils and other synthetic motor oils, should it be necessary to mix them. However, it is important to note that the superior performance of Mobil 1 will be reduced by diluting it in any way.Is there a difference between 5w30 and 10w30?
When to Use 10w30 vs 5w30The only difference between these two oils is cold flow ability: a 10w30 oil will move slower than a 5w30 oil during cold startups. At operating temperatures, both oils will have the same viscosity (30) and will flow and protect identically.What happens if you put 5w20 in a 5w30 car?
No, your engine will be fine with the 5w-20. 5w20 oil is fairly light oil and is generally designed to work with newer engines. Motor oil has become part of a manufacturers program to allow engines to get higher fuel mileage. Lighter oils take less HP to pump through an engine than heavier oils.Does Ford recommend synthetic oil?
Help keep the engine in your Ford or Lincoln vehicle running at its best with a synthetic motor oil that comes recommended by Ford Motor Company. Synthetic oil is engineered to create more lubrication and better performance in the engine of your Ford or Lincoln vehicle. 
William Jenkins 
