Timing chain tensioner goes slack

Tiny
MBLACHFORD
  • MEMBER
  • 2010 FORD F-150
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 154,000 MILES
Hi guys. I've got the truck listed above SuperCrew Lariat with the 5.4 3v engine. I've learned to love FordTechMakuloco on YouTube and i've followed his videos to the letter. I also have the factory ford manuals and a subscription to Chilton online.

Over the winter, I took the engine out and completely rebuilt it for longevity reasons; I like the truck and I want it to last (150,000 miles) Here are the specs:
Block honed and decked with Cylinder heads being reworked with new guides, seals, and valve job
Stock Pistons and Rods with new Hastings Piston Rings
Clevite Mains and Rod Journal bearings
Melling M360HV Oil Pump
Cloyes Timing Chain Guides
Ford Motorcraft OEM Chain Tensioners (updated gasket design)
Ford Motorcraft Timing Chain(s)
Ford Motorcraft Crank Trigger Wheel
Ford Motorcraft Crank Sprocket
Ford Motorcraft Camshaft Phasers
Ford Motorcraft Camshafts
Michigan Motorsports Hydraulic lifters and roller rockers
Mahle Head Gaskets
Dorman VCT Solenoids
Felpro Gaskets
Pennzoil Platinum Synthetic 5W-30 oil (heavier weight than 5W-20)
Ford Motorcraft Oil Filter
Continental Belt and Hoses
SKF Exhaust Headers (cheap)
Stainless Steel exhaust studs and nuts
Dayco Harmonic Balancer
Ford Motorcraft Spark Plugs
New Sparkplug Boots and springs
Original Fuel Injectors sent out for cleaning and blueprinting

Truck has been running just fine after reinstallation. About 100 miles in I started to hear a loud ticking noise at idle that would increase or decrease with the engine RPM, or all together go away when cruising.

I took the valve covers and front cover off and found that the right hand (passenger) timing chain is going slack then re-tensioning again and slapping the top chain guide when turning it over by hand. You can watch the hydraulic chain tensioner loose pressure and retract when the chain goes slack. Okay, replaced the tensioner thinking bad luck and turned it over by hand again. Same problem; new tensioner retracts and the chain goes slack by about two fingers width.

Has anyone ever seen this before? I'm quite confused as to why it's doing this. Left hand (drivers side) is fine.
Monday, June 14th, 2021 AT 6:08 AM

10 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
This is odd but we need to rule out another possible tensioner issue by removing it and compressing it with vice grips to make sure the tension is sufficient.

Also, before you remove it, can you get a video of what you are seeing?

The only reason I am hesitant that this may be a different issue is just because you replaced it already and it is still doing it. Clearly that makes us think there must be another issue.

Seeing the issue may help trigger other thoughts about what this could be.

Also, if you have it assembled right now, can you get a recording of the noise?

Do you have marks on the cover when the chain is hitting it?

The way you described it could also be a lifter issue so let's go step by step and I am sure we will figure this out.
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Tuesday, June 15th, 2021 AT 4:54 PM
Tiny
MBLACHFORD
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  • 6 POSTS
Kase, thanks for taking the time to respond. It's still apart because, well frankly i've pulled it apart three times now and i'm trying to see if this is the source of my tick. I did a video showing the symptoms of what I am seeing which I hope will help.
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Wednesday, June 16th, 2021 AT 1:11 PM
Tiny
MBLACHFORD
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Video attached.
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Wednesday, June 16th, 2021 AT 1:15 PM
Tiny
MBLACHFORD
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The video of it all together and running with the tick I’m trying to eliminate. During this video the OEM CAM Phaser is less than 6 months old (both banks). The tick is more pronounced on the passenger side.

After I took this video I got a new motorcraft timing chain and another motorcraft cam phaser and replaced them (same ones in the video above) with new phaser bolt.
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Wednesday, June 16th, 2021 AT 1:25 PM
Tiny
MBLACHFORD
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  • 6 POSTS
Okay, and I don't have any chain slapping marks on the cover where its hitting. My hypothesis is that the tensioner is vacillating between being pressurized and not, and its causing the chain to go slack then taught causing a slap on the upper chain guide. Happy to be wrong, of course.
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Wednesday, June 16th, 2021 AT 1:36 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
That is interesting. I know for a fact that I have spun this motor over and the chain does go slack in different positions based on valve lift. However, the fact that the tensioner is collapsing like that is a new one. I can't remember ever seeing it that dramatic.

Correct me if I am wrong but that tensioner does not have a seal on the back of it correct? It should be spring pressure only. I think the Left hand is the only one on this engine that is oil pressure filled.

I definitely hear a slight ticking but it is hard to make out. Can you raise the RPM and it gets louder? You said it will increase or decrease with RPM.
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Thursday, June 17th, 2021 AT 8:13 PM
Tiny
MBLACHFORD
  • MEMBER
  • 6 POSTS
No, both tensioners have springs to hold the plunger in place until oil pressure builds, meaning yes they're both oil fed. One random posting on a Ford trucks forum stated that they had a similar issue and the fix was to pull the oil galley plugs at the back and front of the head and to clean any debris out of the head as perhaps there is an obstruction not allowing for full pressure to get to the tensioner. Perhaps i'll give that a try.
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Friday, June 18th, 2021 AT 6:28 AM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
That is funny you mention that. This is why I was asking. I did not see that posting but I was thinking we had a possible oil contamination issue and I thought only the other side was oil feed. Please let us know what happens with this because I am not sure where else to go with this but if nothing comes of this, I have a number of contacts at different Ford dealers that I can run this by and see what they say.

Thanks
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Friday, June 18th, 2021 AT 7:25 PM
Tiny
KF17
  • MEMBER
  • 1 POST
Were you able to get this resolved. I am in the process of doing a full timing replacement on my F-150 and am seeing the same thing. I noticed it after I had the front cover back on and was reinstalling the roller followers. I'm thinking my issue might be related to valve lift as stated above because it didn't start until the roller followers were reinstalled, but I could be wrong. I don't have a great view of the tensioner since the front cover is in place.
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Saturday, January 28th, 2023 AT 7:52 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,256 POSTS
Remember the chain tensioner needs oil pressure to take the slack out of the chain, then it will hold the tension on the chain. Can you upload a short video so we can see what you are talking about?
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Monday, January 30th, 2023 AT 5:06 PM

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