SOHC 4.0 thermostat housing upgrade

[DILLARD000]

I know this thread is a few years old. But I'm about to repl my plastic thermostat housing, was wondering if you might provide some addtl details about replacing these tensioners?

Why would you do this? And any links for a how-to?

Thank You!

Search function on upper right of this page, "Tensioners"
will get you many threads on this subject.

My own webpage on the Tensioners at

Engine Oil Pressurized TimingTensioners

As of this 2020 writing, I'm just dumb lucky, not having had any TimingChain component failure with this 20yr old V6-4.0L~SOHC engine; only issue noticed is momentary rattling during very cold morning starts. The recent removal of the lower Oil Pan & Pump Screen was clean, without any...

2001fordexplorersporttrac.fandom.com

 

[sgtsandman]

I know this thread is a few years old. But I'm about to repl my plastic thermostat housing, was wondering if you might provide some addtl details about replacing these tensioners?

Why would you do this? And any links for a how-to?

Thank You!

The tensioners prevent slack in the chains developing both by spring pressure and oil pressure from the engine. They wear out over time, thus why we recommend changing them every 70,000 - 100,000 miles.

If you don't eventually, they will not keep the chains tensioned, which will allow them to slap on the chain guides, causing accelerated wear and breaking pieces of the plastic off. The procedure for changing the guides is very invasive and will require that the engine be pulled out of the engine bay.

To see what is all involved, watch the videos put out by fordtechmakeuloco. It is a four part series on the job. Something you want to avoid if at all possible.

 

[JJMaine]

Platinum Productions on YouTube also has some good "down and dirty" videos on the 4.0 SOHC.

I think he was just asking about the hydraulic tensioners? I'm pretty sure those can be changed with the engine in. The drivers side you can get to easily while you do the thermostat housing and passenger side I believe is a little more of a pain but doable.

 

[Uncle Gump]

Do the passenger side through the fender well.

 

[sgtsandman]

Platinum Productions on YouTube also has some good "down and dirty" videos on the 4.0 SOHC.

I think he was just asking about the hydraulic tensioners? I'm pretty sure those can be changed with the engine in. The drivers side you can get to easily while you do the thermostat housing and passenger side I believe is a little more of a pain but doable.

He was, from the way I understand it. I answered the part about why it is important to change them.

 

[morsetaper2]

Found a youtube that describes the external tensioners and what it takes to replace them.
EDIT: For future readers, see posts #52 thru 55 regarding TO NOT pre-prime tensioners with oil before install.

 

[sgtsandman]

Found a youtube that describes the external tensioners and what it takes to replace them.

One word of caution, a lot of the how to videos will tell you to prime the tesioners before you install them. Don't do that. It only makes it harder to install them. The one under the intake manifold can be bad enough as it is without making them even harder to press in while trying to get the threads started.

 

[JJMaine]

One word of caution, a lot of the how to videos will tell you to prime the tesioners before you install them. Don't do that. It only makes it harder to install them. The one under the intake manifold can be bad enough as it is without making them even harder to press in while trying to get the threads started.

Do you just disable the fuel pump and crank the engine over a bit before starting to prime everything?

 

[sgtsandman]

Do you just disable the fuel pump and crank the engine over a bit before starting to prime everything?

You don't even need to do that. Just press the gas pedal to the floor. That will put it in clear flood mode and will only turn over without starting.

 

[morsetaper2]

One word of caution, a lot of the how to videos will tell you to prime the tesioners before you install them. Don't do that. It only makes it harder to install them. The one under the intake manifold can be bad enough as it is without making them even harder to press in while trying to get the threads started.

I was wondering about that and was going to ask which way to go with that.

You don't even need to do that. Just press the gas pedal to the floor. That will put it in clear flood mode and will only turn over without starting.

I was going to call BS on that as I swear, that I thought that was what it WASN"T going to do. But sure enough, before posting and making an (ass) out of myself, I better try it first and see.

I'll be damned! All it did was crank, and no fire! Having owned this truck since 2011, I had no idea!

Any other tips for replacing the tensioners?

 

[sgtsandman]

I was wondering about that and was going to ask which way to go with that.



I was going to call BS on that as I swear, that I thought that was what it WASN"T going to do. But sure enough, before posting and making an (ass) out of myself, I better try it first and see.

I'll be damned! All it did was crank, and no fire! Having owned this truck since 2011, I had no idea!

Any other tips for replacing the tensioners?

The one on the passenger, left cylinder head is easy as long as you go through the wheel well.

The driver's side, on the other hand, is in the valley between the heads and under the throttle body and intake manifold. That one is not so easy. Pick your poison on that one, struggle a little more and just Remove the rubber intake hose and the throttle body for a little more room to work. Or, do more work by removing the intake manifold like Ford wants you to do and get much easier access.

Torque the tensoners to spec., restore whatever was taken off, and run the engine to look for oil leaks. When I did mine, the passenger side was good go. The driver's side, however, was not. For whatever reason, the crush washer on that one was being stubborn. It took a couple more tweaks with a box end wrench in order to get it to stop.

Then I mopped up what oil I could and hosed the valley down with brake cleaner as best as I could.

That's pretty much it. I have small hands, so just removing the rubber intake hose and throttle body was fine for me. Not everyone has that luxury.

 

[sgtsandman]

I was wondering about that and was going to ask which way to go with that.



I was going to call BS on that as I swear, that I thought that was what it WASN"T going to do. But sure enough, before posting and making an (ass) out of myself, I better try it first and see.

I'll be damned! All it did was crank, and no fire! Having owned this truck since 2011, I had no idea!

Any other tips for replacing the tensioners?

Ford isn't the only one who does that. The Hondas I had before these did that too. It might be an industry standard but I don't know that for sure

 

[ekrampitzjr]

There are two different tensioners. The longer one goes on the front of the engine by the thermostat housing. The shorter one goes on the back on the passenger-side head. You will need the metal rings (gaskets) to seal the tensioners, and from Ford these rings are separate parts. Anyone know why Ford made one tensioner longer than the other? Here are the Motorcraft part numbers:

Driver's side (LH, long): 6L2Z-6K254-B
Passenger's side (RH, short): 6L2Z-6K254-A
Gaskets (2 total required): XU2Z-6M252-AA

If you haven't gotten your aluminum thermostat housing yet, I highly recommend the Simmons Autosportz version.