That’s a good thought to try and see when/if the part number changes. I will see what I can find. Also, the mega cap part number should be changed.
Members with multi cam phaser replacement...
- Thread starter TheDoug
- Start date
No. A cam phaser job just replaces the broken part with another part exactly like it.
But really, the rattling phaser is just a symptom of the real problem. And it will sound nice and smooth and quiet for a while after the cam phaser job, but will eventually break again because Ford isn’t fixing the real problem.
They will keep fixing the symptom under warranty, knowing that eventually the warranty will run out and they won’t have to worry about it anymore.
Why won’t they have to worry about it anymore? Because Who’s going to bring a 7 year old Expedition with 130,000 miles to the dealership and pay them $3000 to perform a cam phaser replacement job—that they know is just a temporary fix??
Nobody.
No. It’s an oil flow problem.
They tried a more robust “upgraded” cam phaser as their first attempt at solving the problem. My vehicle had those installed. The tech showed me the part number was the new improved part.
They lasted about 25,000 miles.
Ford took several of the “problematic” 3.5 EB’s ( ones that had multiple cam phaser failures)
and did some extensive NDE and instrumented test runs. They installed lots of oil sending units all over the engine to monitor pressure at dozens of locations during the runs.
They found that (on these problematic engines) the oil pressure at the top front of the engine was far lower than expected.
The internal communications article I was quoted from seemed to indicate that although they never found a smoking gun, the most likely failure mode was inadequate mega-cap seal on the final cam bearing closest to the VCT phaser. The theory was that the inadequate seal was allowing too much bypass flow, which meant not enough oil flow, or pressure, to reach the VCT.
You are mostly right on your theory of operation on that mechanical pin inside the phaser, but you are missing the key piece. The reason it pops out and locks the halves of the gear together is not simply because the engine shut down. It’s because the OIL PRESSURE goes away when the engine comes to a stop.
On an engine that is working correctly, as soon as it cranks, the oil pump can get adequate flow and pressure to the top of the engine almost immediately. This oil pressure is what overrides the spring force on the pin and forces it to retract, allowing the VCT phaser to start doing it’s job.
On a problematic engine like mine, the oil flow is not getting up to the VCT quickly. Likely because of a poor seal at the mega-cap allowing far too much bypass flow.
Because of this inadequate oil pressure and flow to the VCT, the little pin stays engaged way longer than it is designed to. When it finally retracts, the engine is probably at higher rpm also. That adds up to a lot of wear and tear over thousands of starts.
And then one day you walk out to start the engine and the pin finally breaks, and your are greeted by the lovely sound of the two halves of your VCT gear slapping back and forth. The dreaded cam phaser knock.
And it is quite that sudden. Your engine may suffer from poor oil flow to the VCT for 50,000 miles and you will have no idea. Until one morning, … Knock knock knock.
Ford knows all this. They hope you don’t.
Thank you sir. By the way, I do believe that there is an oil flow issue in these heads.
On mine, if I rev the engine at idle couple of times pretty fast, there is a noticeable valve clatter. I attributed it to noisy valve lifters, until I realized that these engines have no hydraulic lifters
Try it on yours, give it couple of fast throttle blips and listen carefully right in between the blips,,, you may hear what I am talking about.
Yes I have found blipping the throttle will cause enough clattering to make me cringe. Unfortunately.Thank you sir. By the way, I do believe that there is an oil flow issue in these heads.
On mine, if I rev the engine at idle couple of times pretty fast, there is a noticeable valve clatter. I attributed it to noisy valve lifters, until I realized that these engines have no hydraulic lifters
Try it on yours, give it couple of fast throttle blips and listen carefully right in between the blips,,, you may hear what I am talking about.
A lot of what you are hearing when you do that is the turbo wastegates chattering, I believe.
The mechanical linkage and pivot point hardware is crap on these wastegates and they have so much play in them that they chatter a lot even when you aren’t blipping the throttle, but are especially noticeable when you do.
To further respond to your last question about WHEN the engine redesign occurred. Ford themselves will tell you that 3.5EB’s manufactured after July (?) 2020 are “not susceptible to the cam phaser failures” occurring in prior years.
Want to have fun and torture a service manager at your local dealership? … ask them Why?
scottdm
Full Access Members
Had my cam phasers replaced at 30,000 miles. Seems fine now and I've been cranking for 3-5 seconds before I let the engine start to build oil pressure (I hold gas and brake down and let go of gas pedal) to hopefully reduce long term wear on the new set of phasers. Time will tell if it makes any difference, but figured it can't hurt.
I am familiar with the turbo waste gate noise. What I am hearing is way worse than that, it is for sure base engine noise and seems top end, but why would valve buckets clatter?! I am starting to worry since I can now hear it under load on cold engine. I will try to post a video.
