Cam Phaser or Timing Chain Tensioner

[stkelly]

My 08 Mountaineer 4.6L with 117K miles just started making a pretty awful noise at idle. I know the typical cam phaser hot knock but this is completely different. It sounds like my timing chain or something metal is slapping around at idle on the passenger side bank. The noise starts almost immediately after start up and continues while the truck is idling. As soon as I go above 1200 rpm the noise goes completely away. The truck drives as if nothing is wrong and there are no codes. And I have no idling issues, it doesn't bog down or try to stall. Other than sounding like something is rattling around at idle the truck acts perfectly fine.

I originally thought it was the idler tensioner pulley because that's where I pin pointed the sound with my mechanic's stethoscope. So I completely removed the accessory belt and restarted the truck. The noise didn't change at all. So it's not coming from any of the items along the drive belt. The noise is the strongest right behind the idler pulley. I also hear it fairly well at the passenger side cam phaser.

I'm looking for some opinions on whether or not I have a timing chain tensioner/guide or cam phaser problem. I know something is wrong but I can't really tell which one. The fact that the sound goes away when I go over 1200 rpm points to the cam phaser. But the bearings dropped in a tin can sound make me think it's the timing chain tensioners. I've also tried unplugging the VCT solenoids to see if it made any difference in the sound. It didn't, I only got the expected check engine.

If the timing chain tensioners/guides were shot wouldn't they stay loose and make noise regardless of the RPM? Also, as awful as it sounds the truck drives fine, think I should avoid driving it until I find the source of the sound? It's one of our main cars so I'd have to rent, but worth it if the common thought is that something can go and cause engine damage.

Thanks in advance!

 

[stkelly]

So after letting the truck sit overnight I see that the sounds only happens when the truck has warmed up. It idles fine with no sound from a cold startup. I hear a slight slap when turning it off cold but that's it. Once the engine warms up, it makes the noise consistently at idle until the engine cools completely down again.

 

[Explorer_PL]

Since I rebuilt the timing on my v8, I would say your tensioner is shot. The reason it goes away with RPM is that you build up oil pressure and it applies tension to the chain, once the rpm drops the tensioner gets soft. I was looking how they work when I replaced the phasers, chains, tensioners and guides, but before putting back the front cover. The oil exits the tensioner thru the seals as it's supposed to, but if the seals are shot, then it exits too fast and there is no pressure inside. That also explains why when cold it works better; the oil is heavier so it seals better, then it gets thinner and instead of pushing the little cylinder, it goes out around it.

That was before the change, very slacky chains.

 

[stkelly]

Wow, great pictures! I think you're right. I was just hoping it wasn't the timing chain tensionser because I know it's a lot more work vs replacing the cam phaser. I assume if I'm going to replace the passenger side I might as well do the drivers side. Also, I'm guessing I should replace the VCT solenoids, cam phasers while I'm in there.

How hard was it to redo the timing? A days work if you're mechanically inclined or a full weekend or longer?

Thanks again.

 

[Explorer_PL]

I did it with a friend mechanic watching over and helping. Took us about 5 hours with air tools. My old phasers were still good at 200k so I would not necesarily jump on solenoids and phasers. You can probably do the tensioners without loosing the timing marks. The chains were also in very good shape.

PS: Your 08 requires removeal of valve covers to change the solenoids so you can do them just to be safe. They are not that expensive. On my 06, you could pull them out thru the bigger holes, in 07 Ford "improved" the design of the valve covers.

 

[Joey Threesticks]

My 08 Mountaineer 4.6L with 117K miles just started making a pretty awful noise at idle. I know the typical cam phaser hot knock but this is completely different. It sounds like my timing chain or something metal is slapping around at idle on the passenger side bank. The noise starts almost immediately after start up and continues while the truck is idling. As soon as I go above 1200 rpm the noise goes completely away. The truck drives as if nothing is wrong and there are no codes. And I have no idling issues, it doesn't bog down or try to stall. Other than sounding like something is rattling around at idle the truck acts perfectly fine.

I originally thought it was the idler tensioner pulley because that's where I pin pointed the sound with my mechanic's stethoscope. So I completely removed the accessory belt and restarted the truck. The noise didn't change at all. So it's not coming from any of the items along the drive belt. The noise is the strongest right behind the idler pulley. I also hear it fairly well at the passenger side cam phaser.

I'm looking for some opinions on whether or not I have a timing chain tensioner/guide or cam phaser problem. I know something is wrong but I can't really tell which one. The fact that the sound goes away when I go over 1200 rpm points to the cam phaser. But the bearings dropped in a tin can sound make me think it's the timing chain tensioners. I've also tried unplugging the VCT solenoids to see if it made any difference in the sound. It didn't, I only got the expected check engine.

If the timing chain tensioners/guides were shot wouldn't they stay loose and make noise regardless of the RPM? Also, as awful as it sounds the truck drives fine, think I should avoid driving it until I find the source of the sound? It's one of our main cars so I'd have to rent, but worth it if the common thought is that something can go and cause engine damage.

Thanks in advance!

Agreed with above. I'd suspect the timing tensioner as well. Those cheesy pneumatic tensioners are known for this.

Especially if you're only hearing it from one side as I believe this timing setup has 2 tensioners, 1 on each of the chain cassettes.

 

[stkelly]

Any major risk in continuing to drive it until I get it fixed?

For now, I rented a car for the next two days, I'm having the shop that damaged the motor originally evaluate the truck now to see if there's any warranty work possible (http://www.explorerforum.com/forums/index.php?threads/hole-in-valve-cover-please-help.390513/). The side that's slapping is the exact side they damaged at 70K miles. They rebuilt the motor and put in new chains/guides/tensioners, etc.

Thanks in advance.

 

[Explorer_PL]

If they used some aftermarket parts, the tensioner may be bad again.

 

[stkelly]

So I got my truck back from the shop. They recommended a new engine. They said the oil pressure was too low and that was causing the timing chain to slap.

They hooked up a mechanical pressure gauge and got 28psi at hot idle and 45 psi at hot 2000rpm. The said the spec is 35 idle and 75 at 2000rpm. I looked online and 28psi seems like a decent idle number. 45psi at 2000rpm does seem low.
Couldn't a leaking timing chain tensioner be causing the low oil pressure? The shop was fairly confident that the timing chain tensioner is fine and it's just low oil pressure for the whole engine. They said nothing specific could fix the low oil pressure just to either replace the truck or motor.

I'm going to take the truck to another shop for a second opinion.

 

[stkelly]

I made a quick video of the sound knocking sound:


I'm concerned about throwing money away opening the timing cover if it's unlikely to fix the problem. Any thoughts on the sound and if it's worth digging into further? In the video it sounds like it's coming from everywhere, however it's definitely loudest behind the passengers side timing cover.

 

[Explorer_PL]

I am afraid you will need to take the valve covers and front off. Then you should see some wear marks from the chain hitting something or you would see the guides condition. At that point replace the tensioners, my old ones I could squeeze in my palm, the new ones were hard.

 

[stkelly]

I am afraid you will need to take the valve covers and front off. Then you should see some wear marks from the chain hitting something or you would see the guides condition. At that point replace the tensioners, my old ones I could squeeze in my palm, the new ones were hard.

Thanks Explorer_PL. With the slack you had on the chains did it sound like mine at idle? The reason I ask, I've been researching and found others that thought they had a blown gasket on their timing chain tensioner (they had the timing slap) and still had the problem after doing a timing kit. Turned out their engine was bleeding off pressure elsewhere in the motor (cam journals). In the end they needed to replace their motor.

I looked at the oil flow diagram for the 4.6L 3v and see that the passenger side timing tensioner is the last item to get oil before returning to the sump. I know this is all just a guess without digging into the engine but trying to have the best information possible before deciding to have a shop tear into it. I'm getting independent estimates in the 1,500-2K just to open the timing cover. The dealer was nuts at 4K.

I'd hate to spend the $1,500 and find out it's the head and have to replace the engine anyway. The first shop said to replace the motor and threw out 10K for a possible engine replacement.

I very much appreciate any advice, I know it's almost impossible to give information on this remotely. But hey, any info based on prior experience is great at this point!

 

[stkelly]

Received a second opinion. The next shop thinks it's just the tensioners but isn't sure about the low pressure numbers. However, they're willing to work with me on the labor if it ends up not being the tensioners. Hopefully it is just the tensioners and nothing else.

Thanks again!

 

[Explorer_PL]

I replaced my original engine because 2 shops told me I need a new one and quoted me 4k for a used one and 6k for a new crate motor. At 200k it was a still good strong motor. I put in a used one with 55k miles and the knocking was still there anytime I put in D or R. All the opinions pointed me to the phasers and timing, so I rebuilt the timing on the "new" one and still same issue. In the end it turned out my torque converter was locked up and was never disengaging and trying to stall the engine. $300 for a new TC fixed the issue but I had to pull the motor out again.

This is how it sounded



TC never came thru my mind since on the highway it was just fine, smooth and strong, no shaking whatsoever.

 

[stkelly]

I replaced my original engine because 2 shops told me I need a new one and quoted me 4k for a used one and 6k for a new crate motor. At 200k it was a still good strong motor. I put in a used one with 55k miles and the knocking was still there anytime I put in D or R. All the opinions pointed me to the phasers and timing, so I rebuilt the timing on the "new" one and still same issue. In the end it turned out my torque converter was locked up and was never disengaging and trying to stall the engine. $300 for a new TC fixed the issue but I had to pull the motor out again.

This is how it sounded



TC never came thru my mind since on the highway it was just fine, smooth and strong, no shaking whatsoever.

Explorer_Pl, that really sucks replacing the motor and then pulling it twice. You're definitely more dedicated then I would be!

 

[stkelly]

I was able to get a camera scope into the timing area. Sure enough there is a chunk of the timing chain guide jammed in between the chain. I'm surprised it's just sitting there and hasn't been chewed up by the chain.

At least I'm pretty confident at this point that the problem is in the timing chain area. I'm guessing the low pressure is maybe due to the oil screen being clogged up by plastic bits.

Thanks again for all the help!

 

[Explorer_PL]

Are you going to replace the guides or going for a new engine ?

 

[stkelly]

Are you going to replace the guides or going for a new engine ?

Since the truck hasn't jumped time yet I'm going to replace the chains, guides and tensioners at this point. I'm hoping the low oil pressure is the result of the oil screen being clogged by timing guide parts. I'm having the new shop confirm the oil pressure after the work to see if it's still low at 2000rpm.

 

[stkelly]

Here are some pictures of the timing area. The passenger side guide was broken in a few places:

The drivers side was broken as well, but right around the bolt.

I've heard a few different pressures for these engines at hot 2000rpm. Is 45psi enough at hot (195F) 2000rpm? I just want to make sure I don't have this issue again soon after due to low oil pressure. My Haynes manual says 20-45psi at 1500rpm. However, my Haynes manual is for 2002-2006 Explorers.

Also, the shop suggested I drop the oil pan and clean out the plastic chunks. Makes complete sense I do it, but it's fairly expensive to do and I'm thinking the plastic will be pretty benign in the pan.

 

[Explorer_PL]

Dropping the pan is complex because I believe you need to raise the motor up or something.