Lucky you. My tick showed before 800mi on the original oil. For all I know was there from the get-go, but never noticed it until a month later in my garage.
Well I have done all changes at the dealer using the 5w-20 and the tick comes back every change. It only does it when the engine is nice and warm. I live in a warm climate so I will be switching to 5w30 instead of using Ceratec every change.
5w30 won't make the tick go away either. I use 5w30 all the time now. Even when using Ceratec, I've noticed on occasion the tick is slight in the background, but goes away for the most part.
"Comes back" implies exactly what's being theorized. Oil thins out over time. Frankly, 5w30s two decades ago would be about where most 5w20s are within a short span of time. It makes the "my 199x or 200x lasted 200k on 5w30! Why change?" A silly counter point. Synthetic 5w20 is much more sheer stable, but I digress. The 5w20 you get on a fresh change is more viscous (mind you, not by much) than the 5w20 on its way out. So if the tick goes away and comes back after a fresh change then 5w30 probably won't solve your problem. Try it all you want, there's no harm to it, just don't be surprised if it doesn't fix it or makes it worse.
The oil being "shear stable" has a lot more to do with the oil formulation rather than the oil viscosity. After seeing a lot of UOAs in the Coyote, it looks like Motorcraft shears down worse than other brands.
All things being equal, a tighter spread of the two ratings will have more shear stability. There's smaller (viscosity index improvers) involved in the forumulation so there's less room to break down and cause shearing. That's why 10w30 is still held in high regards (because people love the 30w). Basically a 5wXX (not to be confused with an actual 5w oil) starts with the viscosity that's within the given spec for 5wXX and thins out as it heats up. VIIs are then put in to thicken the oil up to fit the desired rating of the second number (20, 30, 40, etc). Synthetics thin out less than dyno, so they're typically much more shear stable. I've read some PAO basestock oils don't have any VII in the formulation, but this isn't proven and I don't see it being 100% accurate.
Yes, and that further divorces how shear stable a particular viscosity is, because it still goes back to formulation of the VIs more than viscosity. You would really have to look at the new vs used oil viscosity at 40C and 100C in the same motor to see how each specific oil held up from shearing.
I'm not arguing that motorcraft is... meh, oil. It's just hard to determine an oil's resistance on shear at a surface value but it's typically safe to assume a tighter spread is more shear stable. You're mainly talking about 5w20 to 5w30, I assume, which is generally not very different. Look at something like 5w50 and watch that sucker plummet in operating temp viscosity in a rather quick amount of time. A quality 10w30 is some of the most shear stable oil you'll find, apart from running a straigjt 30w.
I'm saying that Motorcraft in the same viscosity (5W-20 or 5W-30) shears more than other brands in the same viscosity. In a Coyote, Motorcraft might typically shear down by 20~25%, whereas another top brand oil will only sheared down 5~10%. And yes, 5W-50 does shear quite a bit because it uses a ton of VIs to achieve that big viscosity spread from 5W cold to 50 hot.
So if I am getting this right, my tick goes away once I put about 2k miles on a fresh 5w20 oil change ( motorcraft) because it has sheered down during that time? I would expect the thinner the oil gets ( the worse my tick would become not the other way around. Maybe I am looking at this wrong. GT what oil would you suggest I go with to help? Every time I get an oil change I want to dump the car it's that annoying. Ceratec seemed to help but I really didn't want to use that every oil change and if something were to happen the possibility of being denied warranty by using that additive. Not saying I would but who knows.
Fact is we don't know exactly what causes the tick so thicker or thinner oil preventing the issue is guesswork. What isn't guess work is that oil does thin out with time, fuel dilution aids this as well. So for everyone who has the tick go away after a couple thousand miles, but immediately return after a fresh change, is having the bbq go away on a thinning oil. Motorcraft especially can thin out quite a bit.
I went with Valvoline Advanced 5W-30 full synthetic. My 2015 GT never really had the BBQ tick, but the Valvoline did make the engine sound better than the Motorcraft 5W-20 did. The top end (cams/valve train) sounds quieter to me with the Valvoline 5W-30.