Yes, you can mix 10W-40 and 5W-20 engine oils, but it's generally not recommended. Mixing oils with different viscosities can result in unpredictable performance and may not provide optimal lubrication. It's best to stick to one type of oil that meets your vehicle's specifications for the best engine protection and efficiency. Always refer to your owner's manual for the recommended oil viscosity.
I don't think I would go with 5w20. I'd probably go with 5w30 and you'll be alright.
Not recommended. The engines call for 5w30 or 5w20.Not recommended. The engines call for 5w30 or 5w20.
Yes, it requires 5w20 or 5w30.
Yes
Yes, you can mix weights but use exactly what the manufacture recommends and do not mix weights.
Even if you can it's not a good idea. These oils have different viscosity and might have different chemical content. When you mix the oils it can change their mechanical properties and the oil will not be as good as when they are separate. You can get special additives to tune 5w20 in something in between 5w20 and 5w30.
not recommended
There should be no problem with mixing them.
Yes of course you can mix them what what would be the reason to do so.
Nothing if they were approved oils. You can mix 10w30 with 5w20 etc. Not a good idea but you can do it. You can mix brands with no problem.
Ford recommends the use of 5w20. In fact, they push 5w20 for all the Modular V8's, and even back dated the older Modulars to use 5W20. They tested the 5W20 Motorcraft oil enough to recommend useage for all the Modulars. That being said, if you have cold winters run 5W20 or 5W30. Because of the engines tighter tolerances, and the OHC design, a thinner oil cold will be a better choice so it flows to the upper cylinder heads quicker. If you live in a hot climate, 10W30 wouldn't be a bad choice, but the 4.6L was designed to use 5W30/5W20. I run 10W30 in the summer, 5W30 in the winter. Hope this helps.
Yes, as long as the ambient temperature is above fifty degrees.