'01 Ranger 4.0L SOHC Thermostat Housing Replacement

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2001 Ford Ranger 4.0L SOHC 150k miles Replacing the thermostat housing as it's leaking profusely. The "center" bolt will not budge. The two on the "outer" came out relatively easily. I've sprayed with penetrating oil multiple times & have let it soak for hours. I'm not very experienced with getting out bolts that are this stubborn. We don't have salt here! smile Since heating it would destroy the housing but it's garbage anyway so don't see where that would hurt. Heating the top would seem to be a waste so would have to heat near the bottom where the threads are located. The head is getting rounded now so not much more to try. I'm trying to replace w/o removing the intake manifold & perhaps that's hindering me more than it should. I had assumed that I could remove the other "sensor" as I'm pulling out the housing. Perhaps not though. Thank you. [Linked Image]
 
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I'd say that outside flange on the head of the bolt is causing extra friction. Does it move as you are trying to turn the bolt head? If not, you might try cutting off a portion or all of it with a dremel tool. This will also allow the socket to get a better grip on the bolt head. I've had good luck using a drill to remove the head entirely. It looks like the shaft (body) of the bolt is long, and will be accessible with vice grips once the housing comes off. Can't tell for sure looking at the picture. Anyway, make sure penetrating oil is getting to all the parts that might be stuck including the threads at that bottom end of the bolt.
 

benjamming

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A swivel joint is required to access with a socket which eventually results in rotating off of the bolt head. A open/closed end wrench doesn't have enough room to access. I've tried a ratcheting wrench that's short but torque is too high for it. I've tried an extractor socket that uses a wrench to turn but the socket rotates off the bolt head. All of which has lead me to believe that the intake manifold has to be removed.
 

benjamming

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No the bolt flange doesn't spin. The concern with cutting anything is getting (small) pieces into the engine. I was trying to avoid that, but perhaps that would be better than removing the intake manifold & all the other stuff as I might have to cut stuff anyway.
 
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Quote
The concern with cutting anything is getting (small) pieces into the engine. I was trying to avoid that, but perhaps that would be better than removing the intake manifold & all the other stuff as I might have to cut stuff anyway.
Cover things and stuff rags in the openings. You'll be OK.
 
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Here's a good thread. One poster mentioned that he had to do this job twice and even with practice he removed the plenum for the second go round. Go here: https://www.ranger-forums.com/4-0l-ohv-sohc-v6-tech-33/thermostat-housing-took-dump-138282/ I also have the source and p/n for a metal replacement many use with success. I just bought one of these vehicles ('05 Range FX4) and the PO replaced it. I still live in fear of the "eventual" splitting of the replacement. It sure seems removal of the air intake (manifold / upper plenum / lower plenum?) is what people do. edit: I found this in my "Ranger Notes": Metal replacement t-stat housing: simmonsautosportz.com p/n SA9, ~$140 Standard replacement "How to": http://bengrosser.com/howto/fordthermostat/ Metal replacement "How to": https://2001fordexplorersporttrac.fandom.com/wiki/Coolant_ThermoStat_Housing Good luck
 

benjamming

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Thanks for the links Kira! I don't plan on buying a metal replacement. If the new Ford plastic part lasts half as long as the original, then that will be 225k miles. I can't see me keeping the vehicle that long.
 
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