I purchased two 2018 Expedition Max's with both with roughly 120,000 miles on them and at the time of purchase the 1-2 second rattle was present as well as a noticeable ticking at idle. It concerned me, but literally of the four I looked at all had the same sound. I had previously always owned GM Suburban's so wrote this off to inexperience with Ford. The one I have personally driven for the last 2 years and about 46,000 miles the startup knocking has increased (gotten worse) as well as the idle ticking. I've had guys in parking lots comment sounds like a diesel. Anyway I took it to the Ford dealer for the CSP's Cam Phasers Campaign #21N03 and PCM Reprogram Due To Engine Shudder Campaign #21N08 and it did not resolve the problem. The work order comments included the significant cam phaser rattle at startup.
Drivability was never an issue, but I was concerned about a failure and possibly significantly damaging something internal or worse having a safety issue on the road. I had four dealers as well as an independent shop quote the repair. I took the list of quoted parts and determined I could buy the OEM parts at at roughly 32% discount Ford dealer $1,264 vs online OEM $858.00. The book repair time was something like 12-15 hours so I figured it would take me a week and I'd need to buy or borrow a few tools. The dealer quotes ranged from $3,552 ($1,464 parts + $2K labor & tax) to $4,227 (parts, labor & tax stated they needed $2,400 down for parts to schedule). Also checked with an independent shop but they simply didn't have time for the job and never gave me a number but backing into it I figured they would have been $500 to $900 cheaper.
The advantage of doing it at the dealer is they are experienced at completing the work as they are doing multiple repairs per week. Also the repair comes with a 2 year unlimited mileage warranty. I figure that had a lot of value and it was worth paying for it to be done right although I would have loved to tear into this myself and learn a lot in the process.
I scheduled the work at the lower cost dealer who also had a courtesy car for my use which I took full advantage of. I also had them replace the water pump with new since it was leaking just enough to consume antifreeze but never show a drop on the ground as well as complete a tune up with plugs, boots etc. They also changed a belt and basically went over anything that made sense. The final bill cam (e no pun intended) out to $4,051.27.
The rattle is completely gone on startup with a quite idle. Just finished up a 2,500 mile trip and the only issue I'm seeing now is an engine shudder on light acceleration or at 1,200 rpm and 30 to 40 mph. If I manually shift down a gear the shudder disappears. So that is the next thing to ask the dealer about as this was not present before they did the CSP reprograms.
For those comments about warranty. Ford told me under 60K miles it was fully covered and then Fords contribution is reduced by 1/3 for every 10,000 miles over 69K with zero covered over 99K. I was well over that so 100% my ticket. Overall I'm not at all happy about that large of a repair bill, but the vehicle is great for road trips with mileage over 20 usually. Having driven two Suburban's over 300K and never having a big expense, it was a lot to swallow. Time will tell if I stick with Ford, but for now I'm happy to have completed the work.