Front Timing Chain Hydraulic Tensioner Disaster Averted

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swshawaii

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1st Gen Owner
V6 Engine
2 wheel drive
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Location
Kailua-Oahu, Hawaii
What engine do you have?
V6 engine
What year is your Sport Trac?
2005
What Generation is your Sport Trac?
1st Gen Owner
Replaced the rear tensioner at 75,000 miles as a preventative measure. Factory install did not have a crush washer so I installed an OE replacement tensioner without one. Factory torque spec for both tensioners is 32 foot pounds using new crush washers or 49 ft/lbs. if reusing. Started at 40 foot pounds and increased in 5 pound increments until oil stopped seeping. Had to loosen and re-torque six times until 70 foot pounds to finally seal. Yikes! STANDARD length 27mm six point socket is much better suited for the rear tensioner with less chance of slipping than the deep well socket required for the front tensioner. Also replaced the common leaking right valve cover gasket that was dripping oil from the outboard rear corner onto the exhaust manifold for a long time. PITA, but finally no more stink. Oil stains ABOVE the rear tensioner is the giveaway.

5000 miles later decided to replace the FRONT tensioner. 2005 Ford Workshop Manual says remove intake manifold and thermostat housing for LH tensioner removal. Almost everywhere else I've read says intake removal is not necessary and to disconnect negative battery terminal, drain coolant below ECT sensor level, remove sensor, throttle body, upper hose to t-stat housing, and oil fill tube for the Job 2 engine. With a 27mm deep well socket, extension, and breaker bar I'm ready to attack. Not so fast. Bottom of intake interferes with socket. Lot's of wiggling and pushing and the socket is on. Tensioner breaks free very easily. Ratchet gets harder to turn the further the tensioner comes out. Socket is rubbing the bottom of the intake. Hear a POP when the tensioner disengaged from the head threads. Oh-oh. Weird sound but it's out. Should have followed the Ford Manual earlier, but to re-install and prevent cross threading loosened eight intake bolts with a 1/4" drive T-30 socket and extension. Also taped the socket and extension together to prevent socket loss in the dark intake "valley". 1/4 inch of extra clearance was all that was needed to prevent the socket from rubbing the bottom of the intake. Cleaned head threads and tensioner contact surface, stuffed paper towel inside the 27mm deep socket so the tensioner fits over tensioner hex without touching the "wave" crush washer. Applied bearing grease to hold the washer centered on the tensioner. Started by hand threading the tensioner from the front of vehicle three full turns. From right side fender with ratchet and extension tightens easily two-thirds of the way then stops. Remove and try threading old tensioner. Same result. Found an M22 x 1.5 tap locally for $80. EXACT same Irwin/Hanson tap from Amazon was $12.44 including shipping. Always prefer supporting local business, but don't support price gouging. I can only believe the increasing down force on the socket when removing the original tensioner caused the piston to strike and damage the inside threads when the tensioner became disengaged from the threads in the head. Lesson learned is BEFORE proceeding LOOSEN THE INTAKE IF IT INTERFERES WITH THE SOCKET. Anything that causes the socket to skew off center is very bad. As mentioned above, factory torque spec for both tensioners is 32 ft/lbs. with new crush washers, or 49 ft/lbs. if reusing. Ended up having to torque the tensioner in the repaired threads to 60 foot pounds after 55 still leaked. Scary torque, especially when so much material was removed from the aluminum cylinder head threads after tapping. Using a very slow steady pull on the torque wrench, and fearing that sickening feeling of threads "slipping", I felt and heard that wonderful click instead. Released, pulled again, and CLICK. Rejoice! Averted a VERY expensive cylinder head replacement, or at the very least a Heli-Coil or thread insert. In my case I only needed 1/4 inch of added wiggle room, but failure to loosen the intake caused a lot of unnecessary stress and wasted time. Luck was definitely on my side.

Top two pics shows socket intake interference.
Bottom two pics shows tensioner with the socket hitting damaged threads and tensioner finally home after repairing threads.
 

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Top pic- Damaged threads closest to plastic timing chain guide.
Bottom pic- Hungry M22 x 1.5 tap.

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Greased flutes caught LOT'S of aluminum bits after tapping.
22mm tensioner port threads in head are only 7/8" deep.

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You're welcome Duncan. Tensioner R&R really is an easy job using the correct tools and taking your time. (Which I obviously didn't) Seems the biggest issue is almost always oil leaks. Crush washers must be perfectly centered and seated in order to seal properly. Problem is the washer's inner diameter is larger than the flange on the tensioner. Washer also has a wave pattern so it doesn't sit flat on the tensioner flange and tends to move or fall off and run down the threads because of the downward angle. A bit of heavy grease to keep it in place helps a great deal. Take your time and keep us posted. Good luck!
 
Duncan, I assume you will be replacing both since you said tensioners. If you've already replaced the notoriously leaking lower t-stat housing you are probably familiar with the tiny metal coolant sensor clips that tend to fly off when removing. I highly recommend using forceps, needle nose vice grips, or a similar tool to R&R the sensor(s). At the very least tie a string or even a zip tie to the clip to avoid losing them in the engine bay. Mine went flying after it came out of the sensor port and took me 30 minutes to find blindly with a magnetic pick up tool. I got extremely lucky finding it because most don't. Dorman #8000019 is an aftermarket replacement clip in case the local Ford dealer doesn't stock them. NEVER been a fan of Dorman parts, but I've read their clip fits like the original. GL
 
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Yes, replacing both. Good tip on the clips.

I’ll have to look back at my records, but I’m pretty sure the lower thermostat housing was replaced several years ago. I had a handful of small things repaired around that time, and I honestly don’t remember if I did it or had the shop do it.
 
Lower t-stat housing is by far the most common failure with the 4.0L SOHC's cooling system. If yours hasn't leaked at the seams yet consider yourself very lucky. Here's a replacement tutorial that has helped thousands over the years.
https://howtoreplacefordthermostathousing.com/

If you plan on replacing it avoid ALL the cheap plastic aftermarket kits and consider one of the new aftermarket aluminum kits.
Here's the Austekk sold by this sites former owner and the original ST guru, Todd Zabbia.
http://www.zabteck.com/thermostats.htm
 
Hands down, the absolute best YouTube 4 part series on replacing the timing cassettes on the Ford 4.0. I currently have around 250k on the stock chains, guides, and tensioners. The engine runs well. I'm debating on pulling the engine and doing this.
pt 1

pt 2

pt 3

pt 4
 
^ Agree 100%. Ford Tech Makuloco (Brian's) videos are BY FAR THE BEST YouTube Ford technical videos found anywhere. What's cool are his videos are 100% info without the filler found by MANY other self proclaimed "experts". So good, even some of the "gurus" on EF fall back on him. Must say his short classical music intros to start his videos are fast forward material for me. LOL
 
^ Agree 100%. Ford Tech Makuloco (Brian's) videos are BY FAR THE BEST YouTube Ford technical videos found anywhere. What's cool are his videos are 100% info without the filler found by MANY other self proclaimed "experts". So good, even some of the "gurus" on EF fall back on him. Must say his short classical music intros to start his videos are fast forward material for me. LOL

I agree.

My dilemma is that my 4.0 has no sign of failure right now. But it has a lot of miles on the unit.

Should I just play the card I'm dealt and wait for failure and then get a total rebuilt unit. Or should I go to the effort and just replace the cassettes as a preventative.

The trucks had oil changes since new every 3-5k. It sounds and runs like the day it was purchased. But it is a high mileage unit.

What do you think?
 
After you read this thread it's obvious I'm no expert regarding hydraulic timing chain tensioners. Strange thing is many reliable sources say Ford's replacement interval is 75,000-80,000 miles, but I've never seen that written in Ford manuals. I believe the key indicators of trouble is a cold start up rattle and chain slap driving in second gear typically between 2000-3000 RPM's. I DID have an intermittent start up rattle regardless of the engine being hot or cold, and don't believe replacing both tensioners improved the condition. If you're at 250,000 miles and haven't experienced any timing chain guide or oil pressure issues you are obviously doing something very right. IMO, keep changing the oil and filter at your present intervals and don't change a thing. Now about your 5R55E @ 250K. You have a "miracle" Gen 1 ST if the transmission has also been trouble free with just routine maintenance. May be time for you to win a lottery.

Here's that "rattle" TSB that lists 2001-2002 Sport Tracs, but doesn't apply to 2003-05.
http://www.bbbind.com/tsb-wiring-diagrams-database-results/?type=TSB&years=2001&make=52&makeDesc=Ford&model=1586&modelDesc=Explorer Sport Trac&system=12&systemDesc=Gasoline Engines&docid=6631419

TSB's and Wiring Diagrams (Register for FREE new account)
https://www.bbbind.com/tsb-wiring-diagrams-database/
 
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@Evox, log in and join the "user groups" for future reference. I'll delete this post after. TIA

https://www.sporttrac.org/account/join-user-groups

EDIT- Thanks for updating Evox. HOPEFULLY those who haven't joined the user groups yet will see this post and use the link above.

Will delete this post by the end of today.

Hey, no problem. Thanks for letting me know.

After reading this thread it's obvious I'm no expert regarding hydraulic timing chain tensioners. Strange thing is many reliable sources say Ford's replacement interval is 75,000-80,000 miles, but I've never seen that written in Ford manuals. I believe the key indicators of trouble is a cold start up rattle and chain slap driving in second gear typically between 2000-3000 RPM's. I DID have an intermittent start up rattle regardless of the engine being hot or cold, and don't believe replacing both tensioners improved the condition. If you're at 250,000 miles and haven't experienced any timing chain guide or oil pressure issues you are obviously doing something very right. IMO, keep changing the oil and filter at your present intervals and don't change a thing. Now about your 5R55E @ 250K. You have a "miracle" Gen 1 ST if the transmission has also been trouble free with just routine maintenance. May be time for you to win a lottery.

Here's that "rattle" TSB that lists 2001-2002 Sport Tracs, but doesn't apply to 2003-05.
http://www.bbbind.com/tsb-wiring-diagrams-database-results/?type=TSB&years=2001&make=52&makeDesc=Ford&model=1586&modelDesc=Explorer Sport Trac&system=12&systemDesc=Gasoline Engines&docid=6631419

TSB's and Wiring Diagrams (Register for FREE new account)
https://www.bbbind.com/tsb-wiring-diagrams-database/

It might have to do with this being a rural Georgia truck. We drive a lot of highway and interstate miles as opposed to stop and go city driving. I'm not exaggerating when I say probably 80% of the miles are "highway miles".
 
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Life has gotten in the way of tensioners, etc., and it will for the next few weeks. This past weekend was an all-day college campus visit for my son on Saturday and my Dad’s 83rd birthday party on Sunday. We are gone for Thanksgiving weekend, and have 5 holiday events between Friday night and Monday night the following weekend. And I have a work trip in between, so no evenings at home.

My wife is suggesting that perhaps life is too busy, and the expense is too great for me to start a new “hobby” refurbishing the old ST, and that the money would be better spent on a newer vehicle. Luckily, there are some used 2nd Gen STs that look promising. I’ll keep you posted. I may get to do the project on my brother’s ‘04 instead of my ‘03!
 
Life has gotten in the way of tensioners, etc., and it will for the next few weeks. This past weekend was an all-day college campus visit for my son on Saturday and my Dad’s 83rd birthday party on Sunday. We are gone for Thanksgiving weekend, and have 5 holiday events between Friday night and Monday night the following weekend. And I have a work trip in between, so no evenings at home.

My wife is suggesting that perhaps life is too busy, and the expense is too great for me to start a new “hobby” refurbishing the old ST, and that the money would be better spent on a newer vehicle. Luckily, there are some used 2nd Gen STs that look promising. I’ll keep you posted. I may get to do the project on my brother’s ‘04 instead of my ‘03!

If you do your own work, the 1st gen ST 4x2s are one of the cheapest and painless vehicles to own. There are lots of other cars and trucks that put a bigger dent in your wallet greater than ST. I have an L322 Range Rover, which even with me doing my own work it is painful to keep it 100% operational. ....but I love it.

I've owned lots of pain-in-the-ass "works in progress" over my life. This ST isn't really one of them. It's relatively simple and easy to work on.
 
Duncan, if you decide to look for Gen 2 ST's you "probably" want to look for a 4.6L 3V (V8) with the 6R60 transmission after all the known issues with the 2001-05 Gen 1's drive train. Also recommend looking at build dates after 12/07 with the upgraded heads that use the single piece spark plugs. Water long under the bridge, but the Gen 1 would have been the near perfect vehicle for me if the proven and almost "bulletproof" 5.0L (302) pushrod V8 was offered as an option. I'm seriously considering the 5.0L conversion. Wish you the best and Happy Holidays! Steve
 
If you do your own work, the 1st gen ST 4x2s are one of the cheapest and painless vehicles to own. There are lots of other cars and trucks that put a bigger dent in your wallet greater than ST. I have an L322 Range Rover, which even with me doing my own work it is painful to keep it 100% operational. ....but I love it.

I've owned lots of pain-in-the-ass "works in progress" over my life. This ST isn't really one of them. It's relatively simple and easy to work on.

I don't disagree, Evox, it has been relatively easy to work on and I've agonized (my wife would say obsessed!) over the decision of what to do with it for a couple of months now. See more below.
 
Duncan, if you decide to look for Gen 2 ST's you "probably" want to look for a 4.6L 3V (V8) with the 6R60 transmission after all the known issues with the 2001-05 Gen 1's drive train. Also recommend looking at build dates after 12/07 with the upgraded heads that use the single piece spark plugs. Water long under the bridge, but the Gen 1 would have been the near perfect vehicle for me if the proven and almost "bulletproof" 5.0L (302) pushrod V8 was offered as an option. I'm seriously considering the 5.0L conversion. Wish you the best and Happy Holidays! Steve

Thanks Steve. I'd prefer a V8, but I put down earnest money on a 2010 V6 4WD Limited this morning. I'll probably pull the trigger after my mechanic checks it out. I'll post details if it works out OK.
 

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