SOHC 4.0 thermostat housing upgrade

[morsetaper2]

The intake manifold is a real PIA! I have a Craftsman deep well socket for the tensioner and it hits the bottom of the manifold before getting to the "bolt" part of the tensioner. I was able to use a 27 mil combo wrench on it but can't get the room to crank it down.

That is why I took off my intake. I understand someone was able to modify a socket to get the tensioner out without having to remove the intake. I don't remember who it was or what Ranger site it was on. Probably TRS.

I was able to get the front tensioner off & I installed the new one this weekend. I'm in the middle of doing a thermostat housing replacement and with all that stuff out of the way I was able to get a deep 1-1/6 socket on it for removal. And a torque wrench on it for the install. Just needed a 3" and a 1" socket extension IIRC.

The Ford tensioners, which I purchased, already come with the sealing gasket in place BTW. I didn't know that when I ordered my tensioners and I ordered gaskets at same time. Was able to return gaskets though.

 

[DILLARD000]

I'm the one who modified the socket to get the Tensioner OUT+IN without removing the Manifold,
just used a grinder to narrow down the drive end of the socket; detailed pics on my SportTrac page
https://2001fordexplorersporttrac.fandom.com/Engine_Oil_Pressurized_TimingTensioners

Can't believe I'm still routinely driving this 25+ year old 2001 SportTrac
(same drivetrain\frame\wheelbase as that years ExtendedCab Ranger);;
it continues to be a reliable and practical vehicle, even with all its original design quirks.
It will happen sooner or later, but I truely dread the day I loose this "old friend".

 

[morsetaper2]

Helpful Hints For Parts (Sensor Clips & Sensor O-rings) When Replacing Thermostat Housing on 4.0 sohc...

The sensor retaining clips from my local Ford dealer are listed at $27.00 each!
Whenever I ask for a discount, the parts guys will apply one. They sold me one for $17.55 - still very pricey for one - but grateful for the discount.

Then afterwards I uncover that Doorman offers a replacement. It is stocked at Rock Auto for $4.52, and at Advance Auto for $10.99 - picture shows two clips, so it may or may not be a pair? Don't know. Doorman p/n 800-019.

Doorman p/n 800-019 @ Rock Auto

Doorman p/n 800-019 @ Advance Auto

And for the sensor O-ring, over on Ford Tech Makuloco's youtube channel he states that the sensor o-ring (not sold separately by Ford, only comes on a new sensor) is a metric o-ring with dimensions of 9mm ID X 2.5mm thickness. I measured the sensor o-ring that came w/ my Simmonz replacement thermostat housing and it was a match.

You can buy 10 of those o-rings in viton (resists ethylene glycol, petroleum products, and other chemicals, good to 400*F at Mcmaster-Carr for about $5+$10 shipping for 10 pcs.

9mm ID x 2.5mm Thk Viton O-ring @ McMaster-Carr

Or I imagine call Simmonz up and they'd sell you one or two.

Also saw in the youtube comments this o-ring at Advance Auto (p/n 24628 & T24628) in some sort of green rubber used in the A/C system. No idea what the o-ring material is though. Don't know if it is suitable for use with ethylene glycol & petroleum products?

Green O-ring p/n 24628 & T24628 @ Advance Auto

 

[morsetaper2]

Back in late Dec 2025 & early Jan 2026, when it was cold as F**k ... My 2011 4.0-sohc thermostat housing was leaking. Look back in this thread (and other threads) to late Dec 2025 & Jan 2026 and you will find some of my drivel about that. I changed the front tensioner while I had the thermostat housing out for the Simmons alum housing replacement I did back then.

I finally got around to replacing the pass side rear tensioner today. Bought both tensioners back in Dec '25. Removed pass side front tire, then the splash guard from the wheel well and it's almost a straight shot in w/ a socket wrench w/ extensions & a U-joint. You'll need a 1-1/16 socket.

While I was in there w/ splash guard off, I changed plugs. Lots of cursing ensued. Seems like you need every option for u-joints, short & long extensions, swivel head ratchets, in 1/4 & 1/2 drive, and on and on. Plugs had 75k miles on them. Was surprised that the gap had opened up well past spec in that time. Color of plugs was normal.

Spark plug change on driver side bank is EZ.

Installed a new air filter as well. Seems to start a little snappier. Throttle response seems a little improved, which I credit mostly to a new air filter.

You gotta love OEM parts. On the pass side, getting to spark plugs is a PIA for this shade-tree mechanic. My hands are chafed and cut up from the tight fit of everything. Getting the plug boots on & off the spark plugs in that tight space would have been difficult if not for the Ford engineers putting features on the OEM plug boots that allow you to grab and hold to pull them off, and push them on. I don't have spark plug boot pliers, but didn't need them. to the Ford engineers on the OEM plug cables and their design!

I'm at 195,000 miles. And this 4.0 sohc still purrs like a happy tabby cat. Even on cold startup.