How to: Replace a thermostat on a 1996 4.0L OHV V6.

[duggyd123]

update wanted to say it was my rubber seal around the thermostat causeing it

 

[jrp267]

You got air stuck in there. Maybe otherwise it is stuck open.

 

[duggyd123]

did you rtplace the rubber seal bud

 

[ben0123]

Thanks a million for the write up and photos! I'll be replacing my thermostat tomorrow!

 

[rickyfB]

GREAT write up and many thanks. Im new here and new to the x. my 96 temp gauge climbs to red about a min or 2 after starting and stays there..will replacing the t stat fix this? ac works fine and heat works fine and truck runs good

 

[RickOTR]

Thought I would add this video on how to change tghermostat on the 4.0 OHV engine.
http://www.youtube.com/watch?v=ozwgznxGeNA

 

[SoNic67]

I just replaced the T-stat but I cannot make it seal - keeps leaking.
On a V8, does anybody know if the t-stat goes in the housing first and then the paper gasket towards the engine block? In the housing it is a little indent that the t-stat sits in but at this time cannot think right...
Is the "sealant" rally necessary? I have tried with and without - still leaks.

 

[123qwerty]

Well, after replacing my thermostat I decided to do a write up on it. If you are needing to replace your thermostat, I highly recommend doing it yourself. It is easy to do, and very cheap.

Note: This is for the 4.0 OHV, not SOHC

First, a general disclaimer: I am not a Ford engineer, and do not work for Ford. Anything that you do, you do at your own risk.

Now to start. It should take about an hour to complete this, but giving yourself plenty of time is the first step. The tools I used are very common, and can be found just about anywhere.

Before you start, drain all of your coolant out of the car. This will make your life a lot easier down the road.

Tools used:
3/8" Drive ratchet
3/8" 2" drive extender
3/8" to 1/4" drive reducer
1/4" drive ratchet
10mm socket
8mm socket
Flathead screwdriver (not pictured)

Parts needed: Thermostat
New coolant

Now, where is the thermostat located?

It is on the end of the hose going to both the engine block and the radiator. It is where the hose bolts onto the block.

First off: The intake needs to go. Take off the latch for the filter, unplug the 2 plugs in the intake, and pull the vacuum line out. Now, unscrew the hose clamp with the flathead screwdriver, and remove intake.

Now there is that throttle cable cover there. That needs to be removed. Take you 8mm socket, and remove the 2 bolts holding that on.

After that is removed, remove the 3 bolts holding the hose on. These use the 10mm socket. It will take some experimentation with the different extenders/ratchets I have listed, but it can be done with just that. When you are loosening up the bolts and removing the hose, be prepared for coolant to leak from there. Have something underneath the front of the truck to catch it, Either an oil change pan or just some old towels.
Once removed, you will see this:

Please note that the thermostat shown in this picture is actually the new one, yours will not look that nice. It will also be wedged in there solid, and take some wiggling to remove.

When you place in the new one, be sure it is aligned the same way, and rotated the same way as the last one.

Now, put the hose back, and tighten in the 3 bolts. Then re-attach the throttle cable cover. Now put the intake back on. Be sure to re-attach both sensor plugs, and also the vacuum line.

Now, refill the coolant and burp the system.

You have now successfully changed your thermostat. Take it for a drive, then check for any leaks.

This is the old thermostat. Note how the gasket around it is worn and chipping.
Just remember, replacing your thermostat is easy to do yourself, and a lot cheaper too. Just take your time, and everything should go fine! If I have left anything out that you think should be added, be sure to add it or let me know!

thanks many!!!!!
followed your steps and did it in 1.5 hours

 

[clamb]

I recently changed my thermostat. I didn't get the OEM Ford T-stat with the air bleed hole on the top, replaced with a Stant 195. To ensure that the system was purged of air I removed the top temperature sending unit, & topped off the rad until I could see the coolant coming up into the hole. I had problems in the past with getting it to circulate. If it is airlocked the Tstat won't be exposed to the hot water, & the engine can get quite hot before it will open & allow the coolant to circulate.

 

[wow97]

i have a 1997 ford explorer limited 4.0 L OHV Cologne SOHC V6.
with 5-speed automatic with 4wd 4x4auto 4x4high 4x4low how many horsepower and torque thank you

 

[sr acalito]

When i open my thermostat housing to change the old one because my gauge is not moving, i was shocked, no thermostat in there. I'm using this car for two years already... I know this reply is so late.. I just wanna share, maybe somebody read this also.. Thanks!

 

[lhbailey]

Charlie and crew,

Thanks for your excellent instructions and photos. Up to now, I've let the men in my life work on my cars... Since there are currently no men in my life, I decided that $200 was too much to pay to a mechanic to install a new t-stat. Egad! I know a guy's got to make a living but $200 to install a $7 part? A full SAE and metric socket and wrench set has been languishing in my garage so I figured it was time to make them useful and today, I did it! I feel so GOOD! No leaks, temp stays in the "normal" range... Yee!

Next is the power steering pump... oh, boy...

 

[moexplorer97]

Glad to have this thread. Need to replace my thermostat, as it is stuck open.

 

[O.G.]

Nice write-up, good pics.

 

[TallGuy]

Thank you soooo much for this thread, just replaced my lady friend's thermostat in her 96 explorer, this thread was picture perfect, literally.

 

[AP9]

When you place in the new one, be sure it is aligned the same way, and rotated the same way as the last one.

This isn't necessary if the new thermostat doesn't have an air bleeder hole, is it? I was under the impression that the rotation of the thermostat only matters so that the air bleeder hole is at the top and thus more effective.

edit: By the way, thanks so much for posting this.

 

[jazzkeys]

Stubborn small leak at thermostat housing

Howdy, y'all,

Coupla years ago when I replaced the leaking radiator in our 1996 XLT (4.0l OHV), also replaced the thermostat as the temperature gauge pointer was hardly moving regardless of engine temperature. I noticed that there wasn't a gasket under the thermostat housing, which seemed strange. I assumed that the flange surfaces were sufficiently-well machined that a gasket wasn't part of the assembly. Of course, the leak continues.

I looked for an exploded-view diagram at fordparts.com, but it only shows the V-8. Can't tell if a thermostat housing gasket is part of the assembly.

Is there a gasket missing? Gotta replace the leaking lower rad hose, so wanna fix all leaks now.

Thanks much.

 

[BrooklynBay]

It needs a gasket. Some performance housings use an O ring.

 

[darknite500]

I drive 20 mins. to work and in that time my temp. gauge is constantly fluctuating from very low to very high and back, also the heater has been blowing out cool air while the setting is on high. Is this due to a bad t-stat?

Also, when you go to put the screws back in, how tight do them need to be?

 

[BrooklynBay]

Welcome to this forum! Don't replace the thermostat until you check the coolant level.