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Need input/advice whether I should attempt Timing Chain Replacement

The pulley looks to be centered relative to the cushioning material which appears to be in good condition. If it were me and the threads are in good enough condition to pull the pulley at least one more time I'd reuse it.

The threads were not perfect obviously, but they did hold and I think they would again. I'll be sure to keep my bolts, etc. on hand in event I have to pull it again.

Thanks,

Chris
 



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And the winner is....

I was able to remove the front cover today.

So from here I need more help...

Everything seems to be ok to me. There is some movement to both the main and balance timing chains, but very little. The main tensioner appears to be the original. The finger on the left camshaft chain is intact.

What else am I looking for?

How much slack or looseness can there be in the main timing chain and balancer chain?

I'm guessing at the minimum I'll be replacing the main tensioner; should I replace the main guide too?

Pictures included. Can provide more at request.

Notes:

- All of the antifreeze was not out of the block when I removed the front cover, so some got in the upper oil pan/cradle. Is this going to be a problem? I'll just have try and get as much out as possible and do an oil change soon after reassembly?

- The cover may have been able to be removed without removing the Power Steering and A/C compressor mount, but it clearly was going to come off easier by moving it out of the way (there was more movement to it than I thought there would be).

- I believe I was able to remove the front cover without damaging the front seal, but I'll have to take a closer look.

Thanks in advance for the help,

Chris
 

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If everything looks good what is the noise that you have?
Bob T
:us:
 






If everything looks good what is the noise that you have?
Bob T
:us:

That's the million dollar question. :D

I had a start up rattle. When I changed the hydraulic tensioners for the left and right cam chains, it got worse and turned into a more often/sometimes constant chain rattle (what appeared to be anyway).

That's kind of why I'm at a bit of a loss. I'm not sure how it got worse, especially if nothing is really wrong.

I figured I disturbed something when I changed those tensioners and it finally broke, but nothing is broke.

I wish I had tried my old tensioner before I tore into the engine, but how often is a new part defective?

Chris
 






A couple more checks

Everything looks good from the photos. The left cassette guide finger, the balance shaft chain and primary chain guides, and the balance shaft chain tensioner. I suggest pressing against the balance shaft chain and primary chain tensioners at the mid-point to make sure the spring leaves aren't broken. My primary chain tensioner looked fine but was exerting no force against the chain because the leaves were broken. Also, check for plastic between the primary chain and the tensioner leaves. It may be worn down allowing the chain to contact the leaves.

My primary chain guide was barely worn even after 150K miles. I wouldn't have replaced it but one came in the kit I purchased.

It's impossible to prevent coolant from escaping into unwanted places. You may be able to blow it out of the block cradle so it drains into the pan and then clean the pan. I have an electric leaf blower that comes in handy on several automotive related tasks. I'm glad to see you don't have an engine full of sludge like mine was. I sprayed Gunk engine flush into my engine and brushed exposed surfaces for days trying to get rid of mine. Put some conventional oil in for engine start and then drain it and replace it with synthetic and install a good quality oil filter with an anti-drain back valve.

Use special care when refilling the block with coolant. I leave the thermostat out and connect the lower radiator hose. Then I add coolant until it reaches the thermostat level, install the thermostat and housing and upper hoses. Then I fill the radiator and make sure the degas tank is at least half full. I start the engine with the radiator cap loose and let the engine idle until the thermostat opens. Make sure you have good ventilation if in the garage. Then I add more coolant until it reaches cap level and tighten the cap. Then I shut the engine off and let it cool and I top off the radiator again. Then I go for a few short drives while monitoring the engine temperature to make sure it's behaving normally. It is difficult to purge the air from the SOHC V6 block. Many members have overheated their engines after performing work that involves coolant loss. I spend the extra time to purge the air and avoid blown head gaskets.

I looked back thru this thread to confirm that your original symptoms was start-up "rattle". I'm concerned because unless I've overlooked a post you haven't found anything yet that would cause the rattle. Did you happen to remove the serpentine belt and run the engine to make sure the source was internal to the engine?
 






I looked back thru this thread to confirm that your original symptoms was start-up "rattle". I'm concerned because unless I've overlooked a post you haven't found anything yet that would cause the rattle. Did you happen to remove the serpentine belt and run the engine to make sure the source was internal to the engine?

I did early on, and I was able to produce a rattle with the belt removed the second time I tried it. But I did not try it again after the symptoms got worse after I replaced the tensioners.

I also inspected the crankshaft seal on the timing cover. It looks like it may have been leaking ever so slightly (there is moist dirt around the seal), however I see all the special tools you need to replace it, so I guess it's staying in.

Yea, I'm not really sure. I sure hope I didn't do all this for nothing. Perhaps the main tensioner just decided to act up at the same time I replaced the hydraulic tensioners. Maybe the replacement hydraulic tensioner is bad... I don't know.

I thought for a moment my oil pump/pressure maybe was an issue, but I've never had low oil pressure at least according to the gauge.

I'll order some parts tonight and work on putting it back together next week. I'll take the other steps you listed upon reassembly, and report back.

Thanks for your help StreetRod.

Chris
 






I think the main tensioner was upgraded with more springs? IRC. I read it in one of the threads.
It could be like Street Rod said: that the tensioner is weak and not putting enough pressure on the chain.

Bob T
:us:
 






Just another thought, things are altogether different when the engine is running. There is a lot more stress on the chains and tensioner.
Bob T
:us:
 






I think the main tensioner was upgraded with more springs? IRC. I read it in one of the threads.
It could be like Street Rod said: that the tensioner is weak and not putting enough pressure on the chain.

Bob T
:us:

You might be onto something there Bob, and you are correct, the tensioner has been improved with 6 springs now instead of 3, from what I've read.

I took the main tensioner off and it really was producing little, if any tension on the main chain. (Not sure why I didn't do this a couple hours ago. Guess I forgot I could take it off without messing with anything.)

I've pressed on the balancer tensioner and it seems ok, but I wouldn't be surprised if it's worn/weak and the cause of some of the rattle. But given it's location, it's going to have to stay put.

The springs seem unbroken on the main tensioner, but I'd definitely say they are weak. You can also see from the pictures the is some wear on the plastic.

Chris
 

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There is quite a bit of wear on it. That allows less tension on the chain.
Bob T
:us:
 












There is quite a bit of wear on it. That allows less tension on the chain.
Bob T
:us:

Agreed. I also just looked at the balancer tensioner again too, and it has wear on the plastic where the chain rides. Unfortunately I believe the engine needs to be pulled to replace that one because it's below the block cradle/upper oil pan.
 












centering the cover seal

I used the harmonic balancer to center the front cover seal horizontally. I just pushed it far enough toward the crankshaft for it to contact the seal and center it. The lip of the block cradle should center the seal vertically. I tightened the cover face bolts first and then the block cradle bolts. Did you separate the water pump from the cover?
 






I used the harmonic balancer to center the front cover seal horizontally. I just pushed it far enough toward the crankshaft for it to contact the seal and center it. The lip of the block cradle should center the seal vertically. I tightened the cover face bolts first and then the block cradle bolts. Did you separate the water pump from the cover?

No, the water pump is still attached. Is it easier to reassemble with it removed?
 






check the bearing

Check the bearing for wear. If there's any lateral or angular play then the bearing is bad. Check the weep hole for signs of leaking fluid. If all checks good then save time and a gasket by leaving the water pump attached.
 






Check the bearing for wear. If there's any lateral or angular play then the bearing is bad. Check the weep hole for signs of leaking fluid. If all checks good then save time and a gasket by leaving the water pump attached.

Cool. Thanks for the advice!

Chris
 






Should I consider pulling the engine and doing a complete chain replacement?

So I still have a concern about the other chains and their guides, specifically the balance shaft chain.

Given what we know about the timing chain guides and their failure rates on the 4.0, and given that my engine has 160k miles on it, should I pull the engine and replacing all the timing components?

My main concern lies with the balance shaft tensioner. If you look at the attached picture, you can see the color difference on the plastic of the tensioner where the chain has rubbed through. In addition, the tensioner seems a little weak to me and I believe StreetRod has said these are known to fail around 150k miles.

Or, should I just replace the main tensioner (which to me clearly needs to be replaced), reassemble, and go on my merry little way, waiting for the other failures later on down the road, if they ever happen (which I'm guessing they will at some point).

At this point, I plan on driving the truck for as long as I can. It's not a daily driver, but more for a cruising truck, used for taking the boat out of the lake and used more during the winter for the 4-wheel drive.

All input appreciated, thanks in advance,

Chris
 

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Your choice

Since joining this forum in May 2009 I don't recall any member posting that engine damage was experienced due to either a failed primary chain tensioner or a failed balance shaft chain tensioner unless particles from them blocked an oil passage. However, the traction side of the rear cassette guide is not reinforced with metal and could fail at any time after 13 years and 160K miles. Pulling the engine now and replacing all of the camshaft timing components could buy you another 10 to 15 years and 150K miles. My main bearings were in good shape for the 150K miles on them so I didn't replace them. With the pre-oiler I expect they'll last another 150K miles. Pulling the engine and the block cradle is not that difficult but it is time consuming and involves more gaskets. On the other hand, I enjoy automotive tinkering more than driving. Whatever you decide, I'm sure you'll get help from forum members.
 



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If you have the time and money and a good place to do it I would say do the whole job. But I don't know what tools and equipment you have. Of course you need an engine hoist.

If the front tensioners are worn then the back are probably worn also.

Bob T
:us:
 






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