Will changing my timing chain tensioners do more bad than good?

[explodermann256]

2007 4.0 SOHC 4WD. I know this topic has been beaten to death but when I cold-start my truck I have a slight rattle which goes away very quickly (unless its REALLY cold out then it lasts a little longer). When the truck warms up the engine is super quiet and has good power. The only other thing that worries me is I hear very faint chain rattle between 2-3k. It's not very loud but I know its there.

Now, I don't believe the chain tensioners were ever changed in here (I'm the second owner, bought it with 119 now at 124k). Is it worth it to change my tensioners and potentially get rid of my startup rattle or will I wind up just breaking the guides by doing so? A friend with a 97 4.0 SOHC Explorer changed his tensioners at 160xxx and two days later his truck was rattling like crazy which leads me to believe he broke the guides. At the same time though, he used crappy no-name tensioners.

Any input would be greatly appreciated, thanks.

 

[Daveb]

I am having a somewhat similar problem however mine is much worse (same explorer) Loud rattling at all ranges of rpm. Have you or anyone else know of a way to test the tensioners? I get oil flowing out of the threaded end when I push the plunger down. I would think there should be a check valve in them but I can’t find any info. Sorry to piggyback but didn’t want to start a new thread on the same subject three hours later.

 

[Littleant]

You are getting your first warning. Chain tensioners are cheap compared to the chains and labor. If it were my vehicle I would do the tensioners. May be all you need but may not. I would also purchase only motorcraft. Amazon has them.

 

[donalds]

Do some research on preoilers

 

[explodermann256]

I am having a somewhat similar problem however mine is much worse (same explorer) Loud rattling at all ranges of rpm. Have you or anyone else know of a way to test the tensioners? I get oil flowing out of the threaded end when I push the plunger down. I would think there should be a check valve in them but I can’t find any info. Sorry to piggyback but didn’t want to start a new thread on the same subject three hours later.

I think yours might be too far gone (as in you need chain replacement). Does it rattle at idle too?

 

[MotorCityFats13]

i also wonder this question since i am worried if i pull out the 2 units there might be parts that just fall apart screwing me over

 

[donalds]

i also wonder this question since i am worried if i pull out the 2 units there might be parts that just fall apart screwing me over

Once you remove the engine for this repair the upper oil pan can easily be removed and inspected

 

[R J Bezesky]

You are getting your first warning. Chain tensioners are cheap compared to the chains and labor. If it were my vehicle I would do the tensioners. May be all you need but may not. I would also purchase only motorcraft. Amazon has them.

I agree completely. I've seen many posts that recommend changing them every 80,000 miles or so. Also only Motorcraft. I put a remanufactured 4.0 in my 2006, I bought it with an exploded motor (timing chain failure) and the new motor rattled at idle with new aftermarket tensioners. I swapped them for OEM and now rattle free. The front is usually more problematic than the right rear because of orientation. The front can leak down its oil prime and when they fail might partially prime or never prime at all when running. The rear is positioned below horizontal. So it holds prime better and in my experience lasts longer. If you bench prime them when they pump up they are stiff and difficult to press the plunger in by hand.

 

[MotorCityFats13]

Once you remove the engine for this repair the upper oil pan can easily be removed and inspected

ill never remove the engine..... if the chains snap the truck hits the crusher

 

[explodermann256]

2007 4.0 SOHC 4WD. I know this topic has been beaten to death but when I cold-start my truck I have a slight rattle which goes away very quickly (unless its REALLY cold out then it lasts a little longer). When the truck warms up the engine is super quiet and has good power. The only other thing that worries me is I hear very faint chain rattle between 2-3k. It's not very loud but I know its there.

Now, I don't believe the chain tensioners were ever changed in here (I'm the second owner, bought it with 119 now at 124k). Is it worth it to change my tensioners and potentially get rid of my startup rattle or will I wind up just breaking the guides by doing so? A friend with a 97 4.0 SOHC Explorer changed his tensioners at 160xxx and two days later his truck was rattling like crazy which leads me to believe he broke the guides. At the same time though, he used crappy no-name tensioners.

Any input would be greatly appreciated, thanks.

Update. I replaced my rear chain tensioner with a new Motorcraft part. I unclipped a smaller portion of the inner fender and cut it slightly to get better clearance. In general, it was pretty easy. The hardest part was getting clearance to the rear tensioner. Also, I had a small issue with the metal o-rings that go around the tensioners. The Ford ones don't come with the o ring and upon removal I couldn't find an o ring anywhere. When I put the new tensioner on it was dripping oil, so I took it off and put the old one back on. Now, the oil leak was gone. I wasn't ready to give up so I took the old one off again and a metal o ring fell on the ground. Go figure. I snapped it on the new tensioner and it was good to go, no more oil leaks. There's debate online as to whether these trucks have o rings or whether you need the o rings and the answer is yes, you do. If I were to do it over, I would buy new o rings. Tightened to 34 lb ft (factory spec is 32). No more rear chain rattle on startup or acceleration, or so it seems. While the old tensioner was out, I stuck my hand inside the hole as well to try and feel for any broken pieces along the guide. The guide moved forward and backward as I assume it should but did not wiggle from side to side, feel scored, or feel cracked.

Next up is the front chain tensioner, which will be done later this week. This one seems to be the louder of the two. I will post an update then.

 

[Explorer_PL]

256
Thanks for posting, can't wait for the front update report.

 

[Littleant]

explodermann thanks for the update. Waiting on second update on the front.

 

[explodermann256]

Front tensioner is in. The removal and installation process was pretty straightforward. I started by removing the pins that hold the coolant temp sensor and a small plastic plug next to it. Then, I removed the those two parts. When I did this some anti freeze came spilling out so I put a cup on top of the engine valley to catch what I could. Then I removed the old tensioner, primed the new one, installed it, and put everything back together.

While I was in there I pushed against the timing chain guide and tried to move it around. It felt solid and looked like it was intact from what I could tell.

Started it up after installation to an initial rattle (my guess is the tensioner had to prime some more) but after it ran fine as it always does.

With that said, however, I'm very disappointed. I went to cold start the truck tonight in 39° F weather tonight and had the same chain rattle on startup as I did before changing the tensioner. My project seems to have been a waste of time. I'm riding the lighting until the chains go though I might look into a pre oiler at some point.

 

[donalds]

Do some research on preoilers

^^^^^^^^^^^^

 

[ptf18]

exploderman. I think I have this correct. Prior to startup push the accelerator pedal to the floor. Crank the engine until your oil pressure gauge shows you have pressure. At that point release the pedal and the engine should start.Your priming the tensioners prior to startup.

Listen for your rattle at the moment of startup.

You can read previous posts about this procedure.

 

[ExplorerDuece]

I have a piggyback question. I know I have a broke chain tensioner guide. Should I replace the tensioners to kill the rattle? The rattle is at startup and idle,I don't hear it work in drive.

 

[boominXplorer]

Front tensioner is in. The removal and installation process was pretty straightforward. I started by removing the pins that hold the coolant temp sensor and a small plastic plug next to it. Then, I removed the those two parts. When I did this some anti freeze came spilling out so I put a cup on top of the engine valley to catch what I could. Then I removed the old tensioner, primed the new one, installed it, and put everything back together.

While I was in there I pushed against the timing chain guide and tried to move it around. It felt solid and looked like it was intact from what I could tell.

Started it up after installation to an initial rattle (my guess is the tensioner had to prime some more) but after it ran fine as it always does.

With that said, however, I'm very disappointed. I went to cold start the truck tonight in 39° F weather tonight and had the same chain rattle on startup as I did before changing the tensioner. My project seems to have been a waste of time. I'm riding the lighting until the chains go though I might look into a pre oiler at some point.

Running an oil filter with a check valve? (Motorcraft, wix or napa gold)

 

[Littleant]

boomin xplorer makes a good point A bad anti drain back valve can and will cause startup noise.

 

[explodermann256]

Running an oil filter with a check valve? (Motorcraft, wix or napa gold)

I always use a motorcraft filter.

 

[explodermann256]

Update. The truck isn't rattling on startup like it was the first day I did the tensioners. Cold started it in 35° F tonight with little rattle. No more rattling when the engine is very cold either after startup. Rattle on acceleration is completely gone, though I hear little "ticks" on acceleration that I noticed other 4.0 SOHC's also make. Not sure if that's timing related or not. Will post another update when it dips below freezing.