New to the forum and read many threads on A/S/S before posting so bear with me. My truck is a 2021 3.5EB Crew Cab Xlt I bought new last year. It was a massive investment for me and I am stressed about maintaining it I had some thoughts on the Auto-Stop-Start feature and have not found a thread that discusses my questions. I know there have been countless threads on Auto-Stop-Start and IF it causes any premature wear of components. I change my oil with Motorcraft filter and oil at the dealer every 5k miles and am a shade tree mechanic who likes to meticulously maintain my vehicles so this is most likely a over-worrying scenario but here is goes.

Initially I was concerned with the usual suspects from the A/S/S feature. Starter, flywheel, battery, turbos losing oil flow, etc. I then read about the more robust starter, battery, flywheel and how the turbos still receive coolant flow when the engine is off. All well and good with me, I can live with that. Then I started to think, what is the Achilles heel of most of these modern engines and to me it is the valve train. Cam phasers and timing chains in particular. I get that there when the truck is off there is still the oil film on journals, lifters, the valve train, and all that so there shouldn't be much wear from a warm startup. I also like how there are now two timing chains and better designed phasers with the more recent 3.5s.

My thought is what happens to the timing chain when the truck is turned off with A/S/S. The adjuster loses oil pressure and there is a very tiny amount of slack the develops in the chain. Then, once restarted the oil pressure must come back up to take up the slack in the chain. The starter turns the flywheel which turns the crank and timing chain and then the cam shaft. all while the timing components are being spun from 0 RPM to 2k+ to take off from an intersection under load. All throughout the engine components there is very tiny amounts of slack in the system that must be taken up by restarting. There is also no centrifugal inertia of the components when the engine is off as there is when at idle which means more force is required to get the components to operational RPM. Is it possible that doing this countless times per day in city driving could lead to premature valve train wear and tear?? Maybe it is insignificant or perhaps the idling creates more wear than being off. Maybe the tolerances are so tight it doesn't matter. I am an engineer by trade but definitely not an automotive engineer so perhaps I am overthinking it or am way off base with my many assumptions.

Wondering this groups thoughts.
Many thanks,

 

Welcome.
Don't have it, can't help you.
My G/F has it on her 2019 Hyundai, which has a 100K drive-train warranty, so she isn't worried about it..
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Common sense tells you it can't be good for it if you know anything about engines.

 

Not that I have the answers , but something to think about.
If one agrees that cold starts on an ICE are harder on the engine than hot starts. Engine already at operating temp.
Then, why does the auto start/stop operate before the engine has reached operating temp or at least close to it?
Extreme cold mine does not operate. Fair weather mine will operate before engine has reached temp.

 

Welcome!
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Google [ site:f150forum.com/f129 auto start stop impact ]
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One thing for sure, your starter is going to wear out sooner and who knows, engine starts are when most damage occurs so could be something to it. It's a ritual with me. Start, check mirrors, fasten seatbelt, turn off auto start stop......

 

I wonder that about the Powerboost option 2021+
I realize the starter is not the normal flywheel type but that engine start/stops many times compared to just when stopped. Came out in 2021 so no long term history yet.

 

Not a Power Boost, but Toyota Prius has been around a long time, and they don't seem to suffer.

 

I turn it off every time I start the truck. Not that I worry about it wearing out parts faster, I just hate it. It’s annoying.

 

Same here. Then every once and awhile I forget to turn it off, and the truck shuts off at a red light and I freak out for a second and then press the button. lol