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Chris, Auto Service Technician
Category: Car
Satisfied Customers: 13644
Experience:  43 years of automotive repair, Smog license
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I have a 2008 Ford F 350 with the 6.4L. I was towing a large

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I have a 2008 Ford F 350 with the 6.4L. I was towing a large 5th wheel last week in difficult circumstances and I reached an engine coolant temp of 220 degrees. Long story short I think I have an open thermostat. Where are they located and are they difficult to change? I think there are two of them? About how long will it take? Thanks

Hello and thank you for allowing for me to assist you. Yes there are 2 thermostats, and here is the procedure to replace them. It is about a 3 hour job.

I hope this helps, and let me know if you need further assistance with this.






NOTE: Removal of the vertical EGR cooler is not required to service the thermostats.

1. Remove the upper cooling fan shroud.
2. Remove the degas bottle.
3. Using a mirror, find the end of the upper radiator hose spring clip. Remove the spring clip, disconnect the upper radiator hose from the thermostat housing and position the upper radiator hose aside.
4. Remove and discard the nut and the vertical EGR cooler lower clamp.
5. Remove the bolt and the vertical EGR cooler lower bracket.

6. NOTE: The 6.4L diesel engine uses 2 thermostats.

Remove the bolts, the collar and the thermostat housing.
^ Lift the bottom of the collar up and rotate toward the engine to remove.

7. CAUTION: If the thermostats are contaminated with engine oil, new thermostats must be installed. Reusing a thermostat that has been exposed to engine oil may result in engine overheating.

Remove the thermostats and the gasket from the thermostat housing.
^ Discard the gasket.

1. Install a new gasket and the thermostats into the thermostat housing.
2. Install the thermostat housing, the collar and the bolts.
^ Tighten to 13 Nm (10 lb-ft).
3. Position the lower vertical EGR cooler bracket and loosely install the bolt.
4. Install a new vertical EGR cooler lower clamp. Tighten the clamp nut in 3 stages.
^ Stage 1: Tighten the nut to 10 Nm (89 lb-inch).
^ Stage 2: Loosen the nut 720 degrees (2 complete turns).
^ Stage 3: Tighten the nut to 8 Nm (71 lb-inch).
5. Tighten the lower EGR cooler bracket bolt.
^ Tighten to 62 Nm (46 lb-ft).
6. Connect the upper radiator hose to the thermostat housing. Install the spring clip.
^ Verify the spring clip is correctly seated.
7. Install the degas bottle.
8. Install the upper cooling fan shroud.






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Customer: replied 4 years ago.

Ok, Im down to the last two upper thermostat housing bolts. How or what assortment of tools do you use to get these two bolts out?? Thanks in advance. Doug.

I believe I use a 1/4 inch drive wobbly socket and a medium extension connected to a 1/4 inch ratchet wrench to get to those bolts.



Customer: replied 4 years ago.

Chris. I call B.S. (LOL) on getting the thermostat housing out with out moving the first EGR cooler. Job went well, thanks for your help. Doug.

I agree. I do not know why they mention that the cooler does not need to be removed. You are welcome Doug, and thank you for the positive rating!







Customer: replied 4 years ago.
Hey Chris, Doug here again with another F 350 6.4 question. Check engine light is on. Code says # XXXXX glow plug fault. Which side is #6 on? How many hrs? Can you provide me with instruction as last time as they were very helpful. Thanks, XXXXX XXXXX good week end. Doug.
Sure Doug as soon as I get home from work I will send you that info. I am on my Android phone at the moment.


Ok I am at home now and glow plug #6 is the 3rd one back on the left cylinder head.


Customer: replied 4 years ago.
About how long? Do you have any directions for removal?

It takes about 1 hour to do, and there is a special tool used to remove it.

LH side
4. Remove the LH fender splash shield.
5. Disconnect the 3 wiring harness in-line electrical connectors at the LH frame rail, detach the electrical connectors from the bracket and position the wiring harnesses aside.

Both sides
6. If necessary, detach the glow plug wiring harness retainer.

7. CAUTION: Do not disconnect the glow plug electrical connector before dislodging the seal from the valve cover or the wiring harness may be damaged.

NOTE: Use a tool such as a body bone or trim fork to dislodge the seal. Do not use a screwdriver.

Using an appropriate tool, dislodge the glow plug wiring harness seal from the valve cover.

8. Disconnect the glow plug electrical connector by pulling on the glow plug wiring harness tee above the seal.

Zoom and Print Options64_fm08fstrk2_30307b-007a.png

9. Install the special tool.
10. Remove the glow plug.

Here is a picture of the tool in use.


Customer: replied 4 years ago.

Morning Chris. For some reason I cant open any of the pictures you sent? Can I buy the tool from Ford(part#)? or can I get it from Snap On? Is the wiring harness part of the glow plug? Or does it just disconnect from the glow plug? Thanks

Hmmm, Not sure why the pictures did not show. You can get that tool from Snap On, and yes the harness will disconnect from the glow plug just grab hold of the Tee on the harness to disconnect it.



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Customer: replied 4 years ago.

Ok Thanks. Wont be till next week before I try. I will get parts and tool first. Thanks for now.

You are welcome Doug and thank you again!

Customer: replied 4 years ago.

Hey Chris, I talked to Snap On today and my dealer cant come up with anything? Can you give me the name of the tool and or maybe a part number? If you wouldnt mind could you try and send me those pictures again, so I can identify what the tool might look like. Thanks

Sure Doug, let me see what I can find,



Ok, I found this web site that will sell you the sleeve tool. Click on this link to check it out.







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