08 GT Slight Rattle Under Cam Cover

AnotherS197

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Update 10/24: Noise is still there. Phaser?

Hey everyone,

Happened to be under the hood for other reasons, and noticed a slight rattle coming from the front of the driver's side cam cover right where the phaser and timing chain are. It was so quiet I could barely hear it without the stethoscope, but it's clear as day with it. The passenger side makes no noise.

I pulled the cam cover and everything looks great from the top as far as the guides and everything go.

I believe it may be the o ring on the back of the plastic tensioner starting to fail, as anywhere above idle the rattle went away. My theory is above idle, the o ring is still able to help it build enough pressure to do its job, but the o ring is on its way out. It sounded exactly like when adjusting a manual cam chain tensioner on a sport bike and you've got it too loose.


Does this sound as though I'm barking up the right tree? I'm only at 65k miles but I've heard of stranger things happening. Just want some input before ordering parts. I've never heard what a failed phaser sounds like, but the o ring seems to make logical sense to me.

Thanks.

EDIT: Also curious if anyone has had any luck pulling the timing cover and replacing just the tensioners without having to retime.
 
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AnotherS197

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Also, does this appear to be normal cam wear? Doesn't catch the finger nail whatsoever. I seem to remember similar marks on my original cam, but figured it was worth asking those more experienced.

2vv2z6c.jpg
 

Dino Dino Bambino

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I believe it may be the o ring on the back of the plastic tensioner starting to fail, as anywhere above idle the rattle went away. My theory is above idle, the o ring is still able to help it build enough pressure to do its job, but the o ring is on its way out. It sounded exactly like when adjusting a manual cam chain tensioner on a sport bike and you've got it too loose.


Does this sound as though I'm barking up the right tree?

Yes, and the picture in your last post shows a normal cam wear pattern.
 

eighty6gt

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Probably nothing, check the thread in chit chat about getting some offshore headers and an off road mid pipe!
 

AnotherS197

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Thanks guys. I'm too particular about my stuff to just assume it's nothing unfortunately. Ordered up some tensioners tonight and misc for taking the front cover off, hopefully it'll all be back together by the weekend.
 

RED09GT

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A rattle like noise that goes away above idle could definitely be a bad cam phaser. Can you post a video?
 

AnotherS197

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I'll attempt to. I tried to take one but it's extremely quiet. Like I said, closest way I can describe it is it sounds like a loose timing chain on a sportbike dohc motor with a manual tensioner.

It's also very much a rattle and not a knock like people describe the phasers as. Again, I've never heard one, though. I'll try to upload it to YouTube now.

EDIT:

Excuse the video, obviously going for the sound here. You can best hear it starting around 8 seconds and after I believe. Kind of a higher, scratchy, rattle noise. Hard to discern from the cams with the thin walled stainless headers, but it's there. Silent once I move to the passenger side.

 
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Dino Dino Bambino

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Yeah, it does sound like a timing chain rattle. Possible causes are a worn chain guide or broken tensioner. Either way I'd fix it quick before the chain jumps and the pistons smack into the valves.
 

AnotherS197

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Yup, guides look pristine from the top so I'm just replacing the tensioners unless I find anything else amiss under the front cover.

Any tips when it comes to pulling and replacing the cover? Thought I read somewhere the gasket likes to tear so I ordered new ones. Good to leave the current front main seal in if it's not leaking?
 

eighty6gt

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Front main is difficult to drive in square with the cover off. There are no locating features. If you have a good way of pressing it in (I used a seal driver and still wasn't really happy...) then go for it. Cheap.
 

RED09GT

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Always hard to tell without being there in real life but it sounds like a phaser tick to me. That is how my 2004 F150 with failed phasers sounded. It cleared up at around 1200 rpms.
 

AnotherS197

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Always hard to tell without being there in real life but it sounds like a phaser tick to me. That is how my 2004 F150 with failed phasers sounded. It cleared up at around 1200 rpms.

Making me a little nervous there, lol. Hoping for the best with just the tensioners for now I suppose. I should know this weekend. If not, at least I won't have to take the front cover back off as long as I do it correctly.
 

AnotherS197

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Well chain just jumped while finishing up the right side of the motor. Gonna call it good for today. Supposed to rain all day tomorrow so should be a good day for working on the car.

FWIW, the o ring didn't look too terrible on the driver's side. Did have a weird split but still should have sealed. Regardless hopefully everything turns out alright and my issue goes away. Everything else looks pretty healthy.
 

AnotherS197

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Alright, well, noise is still there. Definitely most prominent towards the front of the motor. Possibly phaser then as Red09 said? I'm not sure what else it could be. Definitely looking for input. To be clear the only thing I've replaced so far is the tensioners.

Edit: I've been thinking more, and it only happening at warm idle along with the frequency seems to rule out a failed follower or lash adjuster, no? I feel all that's left is the phaser...but after already throwing parts at it I'm hesitant to continue doing so.
 
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rickf

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Find someone with a high end scanner and see what the cams are doing. If they are jumping around or wandering you have your answer. Trying to get us to tell you what you want to hear is not going to happen. We can only tell you what we THINK it is, not EXACTLY what it is. The only way to know that is the tear into it and look at all the parts. I have the same issue and the only way I am going to find it is not pester everyone here over and over, I am going to pull the front cover and see what is there. I am most likely going to just buy a complete timing kit and replace it all since I have 90,000 on mine. I am already in there so get it done and that is it. Taking the front apart is pretty easy on these compared to most cars.
 

AnotherS197

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Find someone with a high end scanner and see what the cams are doing. If they are jumping around or wandering you have your answer. Trying to get us to tell you what you want to hear is not going to happen. We can only tell you what we THINK it is, not EXACTLY what it is. The only way to know that is the tear into it and look at all the parts. I have the same issue and the only way I am going to find it is not pester everyone here over and over, I am going to pull the front cover and see what is there. I am most likely going to just buy a complete timing kit and replace it all since I have 90,000 on mine. I am already in there so get it done and that is it. Taking the front apart is pretty easy on these compared to most cars.

Already had the whole front apart. Everything appeared to be in great shape. I realize the only thing I can ask for at this point is what people may think it is, and that's all I'm asking for. Just someone who maybe has experienced this noise previously and found a fix.

There's only so much you can do on the internet and I definitely know that. The only thing I want to hear is someone who has seen this noise before as I'm scratching my head at this point.

Heck I'm open to guesses if there's some logic behind it.
 

AnotherS197

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Time for an update since I hate threads without a conclusion, so here's half of one. Had a work incident that put 9 stitches in my finger so that slowed me down a bit but I think I got it.

I believe its the integrated pcv valve in the valve cover. If I unplug the vacuum hose going to the manifold and plug it with my finger and let it return to idle, the noise is completely gone.

May be time for a set of ford racing covers unless someone knows if you can change them out somehow. I haven't seen any way, though. Also wondering if anyone has seen or heard of this before as I sure havent, and if this even makes sense...
 
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rickf

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There is no PCV valve on a 2008 and there should be no hose going to the manifold. There is a hose going to the air intake before the throttle body but there is no vacuum on that line. The only hoses with vacuum on them go to the fuel pressure sensor and to the power brake booster. They are Tee'd to one line at the rear of the intake manifold back at the firewall.
 

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