I'm so sorry for starting another thread on this topic... Ever since I bought by 2019 Expedition max there has been a rattle from the engine compartment on cold start. I have literally spent hours reading these forum posts and watching YouTube videos. From what I learned, I self-diagnosed it as being wastegate rattle. I'm totally not qualified to diagnose, but there you go.
Anyways, I took the vehicle to my Ford dealership today to have the failed center brake light replaced under warranty, and I mentioned to the guy that there's a rattle in the engine compartment on cold start; if they have it all day and start it after it has cooled down, can they check it out? He said right then it's cam phasers. I asked how they know that the rattle isn't the electronic turbo wastegate, and he said that isn't a possible rattle, but "cam phasers go out on all these vehicles, so I'm sure that's what it is". He then called me an hour later and said the rattle is definitely from cam phasers, and he wants the vehicle for several days to replace them. Odd since the vehicle didn't even have time to cool down enough to replicate.
It's a bummer how experience can vary from one dealership to another; some complain that their dealer refuses to fix the problem, while mine is so anxious to jump on it. I'm thrilled they want to fix my problem, but my question is: HOW DOES ONE DETERMINE WHETHER THE RATTLE IS CAM PHASERS OR THE WASTEGATE? I'd love to feel confident that it has been properly diagnosed rather than diagnosed based on assumption because I really don't want the engine opened up if it's a different issue, and the guy I spoke to did not instill much confidence for me.
I need the vehicle tomorrow so told them not to start the work and will schedule it for after boating season ends when I don't need the vehicle. He told me that's a terrible decision because they could go out any minute and leave me stranded. I thought that was odd as well because from what I've read in other posts, Ford doesn't even think it's a problem that needs fixed.
Anyways, here's a sound clip but not very good... The rattle in this clip sounds so much worse than it actually is. Standing next to the car you only notice it if you're listening, and it just sounds like an exhaust hanger is loose.
https://drive.google.com/file/d/10TqS3epotFVIQo_Lv3-puTUzAL5RyKfg/view?usp=sharing