I have an issue when starting truck after it sits for several hrs or overnight....when you turn the engine over and it starts ..it revs up and rattles..sounds like front timing chain noise...the truck revs up for approximately 1second then comes back down to normal idle and rattle goes away after motor warms up.Mechanic replaced timing chains front and rear and guides tensioners etc...approx 7,000 miles ago...now it has been diagnosed and mechanic says front Chain tensioner is bleeding down(failing) and needs to be replaced...Are the aftermarket timing chain kit parts quality parts...I was told that I might want to get an updated tensioner directly from Ford..What Is your best advice.. I am in need of some mechanical advice PLEASE

 

The 3rd party timing chain kits are fine to use
But ONLY use Motorcraft tensioners, period

 

What I would do, assuming 2005 V6~4.0L~SOHC:
~ Remove lower oil pan, look for broken plastic pieces from TimingGuides.
~ If plastic pieces are NOT found, adjust IACValve to minimize starting RPM flare.
~ Replace both OilPressurized TimingTensioners with Ford\MotorCraft parts, not Cloyes\Melling\Chinese... What brand was installed 7k miles ago?
~ Switch to 0w30~FullSyn (0w20~FullSyn for cold climate) to get oil ASAP to TimingTensioners at cold start, or better yet install a Pre-Oiler.
More info at links below.
Hope this helps.
https://2001fordexplorersporttrac.fa...Oil_Pan+Screen
https://2001fordexplorersporttrac.fa...toControlValve
https://2001fordexplorersporttrac.fa...mingTensioners
https://2001fordexplorersporttrac.fa..._Change+Filter

 

I am not sure what brand was used ...the timing chain kit manufacturer wasn’t something that crossed my mind until now...I will ask the mechanic and see what brand he used.I was told that a Ford dealer would b the best bet for getting good quality tensioners to replace these failing ones...

 

so I don’t need to drive this vehicle...until I get the new tensioners installed...? And are there more than 2 tensioners on this motor... I called the Ford dealership to check on getting Ford tensioners...and parts department said that there was one on top of motor and one on the bottom of front of motor....?
I thought there was one on top of motor...and one that was accessed by removing the passenger side front tire...??

 

There are 3 but the 2 long chain tensioners are the ones that failed
Top front drivers side
Lower rear passenger side

3rd one is behind the timing chain cover on the front center of the engine, like most OHV engines have

The 2 long chain tensioners can be purchased separately, they look like these: https://www.ebay.ca/itm/Ford-4-0L-Ri...-/191450881556

Top front drivers side is the longer one

 

SO HOW BIG A JOB IS IT TO REPLACE THE TWO LONG CHAIN TENSIONERS? WHAT SHOULD I DO AFTERWARDS TO HELP KEEP THIS FROM HAPPENING AGAIN IN 7,000 miles

 

The "rattle" means a guide has broken, so damage is done, replacing tensioner won't help at that point, but you can try it, you would need a new tensioner in any case

You need to pull out the engine to replace the rear chain and guides, so a big job, if its just the front passenger side it can be done with engine in the vehicle

You just need to use Motorcraft tensioners and change them every 100k miles, the chains and guides can be any brand

If its only been 7,000 miles then some was wrong with installation, or it was a 3rd party tensioner, not Motorcraft

The 4.0l SOHC was a good engine, 1997 to 2003 just had poorly designed tensioners, with a higher than expected failure rate, new design works well

 

Click here & read
http://2001fordexplorersporttrac.fan...mingTensioners

 

So my mechanic said the front tensioner is the one that is failing(causing the rattle at startup / idle ....and he is in the process of replacing both front/ back tensioners...says that will solve this startup issue..... But what your saying is the opposite.... that replacing tensioners isn’t going to fix anything...correct?

 

@clovis67
You're wanting a "gauranteed fix"; no such thing with this issue.
RonD, can certainly speak for himself, but my interpretation of what he is saying is
replacing the 2 OilPressurized TimingTensioners is the first step to try; if it fixes the cold startup rattle, wonderful!
This is a "roll of the dice"; the plastic TimingGuides\Cassettes, held tight by those Tensioners, may (or not) already be damaged; not wonderful.
Be patient & know what you want, hold onto to your shorts\wallet & see what results.
Commercial mechanics\shops are like wolves, they sense & take advantage of ignorance\weakness\desperation.
Have your mechanic show you & let you "feel" the new Tensioners, they should be MotorCraft (not Cloyes, Melling, Chinese...)
Then show you the 2 old Tensioners; they're likely "crusty" & hard to compress\rotate compared to new.
Take pics of both; MotorCraft has specific part\date coding engraved on the shell & outer end.
If new tensioners quiet your engine, have him do a fresh oil+filter change after changing the Tensioners.
If they don't quiet your engine, then you've got some harder\pricier choices to make.

 

SO I LOOKED AT THE TENSIONERS THAT HAD BEEN INSTALLED WHEN NEW TIMING CHAIN KITS WERE INSTALLED...AND THE TENSIONERS WERE NOT CRUSTY OR HARD TO COMPRESS . THESE TENSIONERS WERE REPLACED WITH NEW ONES....START UP REV AND RATTLING IS STILL PRESENT....DO THE TIMING CHAIN GUIDES ON FRONT NEED TO B REPLACED?. The rattle is in the front of the engine when it’s starting up cold/or idling

 

@clovis67
Now you've got harder\pricier choices to make.
Only way to confirm what is broken is to start looking, meaning $$$ to
~ remove Left &\or Rght ValveCovers, inspect those Timing parts
~ remove Belt+Fan+WaterPump+FrontChainCover, inspect those Timing parts
It's an economic decision; keep this vehicle running or other options, which is worth the cost & best for you?

 

so motor runs good has no power issues ..just the start up rev/ rattle.....so your saying it is time to get to replacing timing chain guides most likely..

 

Saying it's time for you to choose what to do next.
The options in front of you all have expense, risk, consequence.
Folks here can only feed you info based on their own experience.
You are the only one who can choose.

 

so the rattlin at start up and idle is definitely coming from the front of the engine...so you think it’s best to start by pulling front timing chain cover and seeing what is possibly damaged? The mechanic doesn’t seem to think that the guides are damaged...I just want to get this hi rev at start up and rattle fixed..asap

 

Yes, visual inspection would be the next step, all there is is "best guess" until you find the source of the "rattle"

This thread has lots of pictures of timing chain setup in the 4.0l SOHC: https://www.explorerforum.com/forums...cedure.316471/

You can see a lower timing chain in some pictures which is not there on most 4.0l SOHC engines, it was added in the early years for 4x4 vehicles with LIVE AXLE 4WD, it turned a balancer shaft to offset the possible front driveshaft vibration at higher speed, which didn't occur so it was dropped on later years

 

SO WHEN YOU HAVE TAKEN THE VALVE COVERS OFF AND THE FRONT TIMING CHAIN COVER....AND INSPECT THE SITUATION ....AND SAY THE TIMING CHAIN GUIDES IN THE FRONT ARE BROKEN AND NEED TO BE REPLACED....AND YOU REPLACE THEM......HOW DO YOU DETERMINE WHAT ACTUALLY WAS THE ROOT CAUSE OF THE PROBLEMS....THIS VEHICLE JUST HAAD NEW TIMING CHAIN KITS FRONT AND BACK AND A HIGH VOLUME OIL PUMP INSTALLED 7K MILES AGO?

 

Turn CAPS off

The root cause of the problem was the 2 long chain tensioners, you need to use motorcraft tensioners only or problem will repeat
Also need to pre-load tensioners by compressing them in oil so they suck in the oil and become hard to compress, then install them

And could have been a bad guide, it happens, manufacturing is not an exact science for parts like these, as far as I know they don't x-ray each part for fractures before its boxed and sent out

 

If it looks like a pig, oinks like a pig, smells like a pig, it's most likely a pig.
Using none-Ford\MotorCraft substandard (Chinese?) tensioners, are a long known notorious cause of plastic guide failure.

 

The long chain guides to the cams are not always the ones that that fail. I recently did a complete cam timing chain system rebuild. At 250K miles the right and left guides were still in good condition. However, it was a good thing I did the work because the mechanical tensioner for the chain that goes from the crankshaft to the jackshaft was totally broken off and in pieces. It appeared to have been broke for a long time. The main timing chain was just flopping around. I am surprised I didn't hear a rattle all the time. I would occasionally hear a little rattle at start up but nothing really loud.

You should be able to take off the driver side valve cover and look down inside where the chain is with a light to see if there is any damage to the guide. You will need to take the front cover off to see if the main timing chain (crank/jackshaft) tensioner or guide are damaged. You should not have to take the engine out for that. You should not have a balance shaft, but if you do, that requires removing the pan to repair anything there. You should be able to tell if anything is broken there with just the front cover off.

My brother, who is a mechanic with his own shop, suggested taking the plug with an Allen head recess near the front hydraulic tensioner out to make sure the oil passage there is clean and free of particles. He had heard that the oil passage can get clogged and restrict oil flow to the tensioner. Mine was totally clean, but it is an easy check. At least is was with the engine out and everything apart to do the parts replacement for the timing chain system. It may be more difficult with the throttle body and thermostat housing in place.

 

Thank U all very much.....really appreciate all the great knowledge and advice.... my mechanic didn’t have any idea about the tensioner issues when he replaced the timing chains/kits....So he is scratching his head.... thinking what next??
caps were on cause I don’t see little setters so good...I wasn’t meaning anything by using all caps...👍

 

Well it’s been well over 2 months since this rattling and erving issue was 1st looked at by mechanic.... Mechanic was running behind...but finally today told me that he has pulled the oil pan and the valve covers and has decided to pull engine and replace front and rear timing chain guides and tensioners....so my question is ... what do I need to know about this predicament..in order to make certain that this timing chain cassette/tensioners replacement is all that is needed to fix the rattling and hi rev at start up problems... I am almost 3 months without this vehicle... and really don’t know what to expect ... this mechanic said he never had any previous knowledge of the tensioner issues...and even after I had told him about the issue w aftermarket tensioners...he still didn’t use the suggested Ford/ Motorcraft tensioners... so now the 3rd time around we are using the Ford Motorcraft ones... 🙄

 

Honestly, considering the ignorance & issues you've described with your mechanic,
I would
~ not give his shop another dime,
~ tow this vehicle to my own driveway\garage,
~ take time+effort to study+learn what's needed,
~ pull\rebuild\reinstall the engine myself.
At least then you know exactly what parts are used, what work has been done,
& then only have yourself to blame for mistakes or credit for a quality job.