Lower thermostat housing question...

[drewmar74]

I will preface this post by saying that I have looked everywhere for a definitive answer for my questions already both on this board and on the web in general. This isn't a lazy request for easily found information but a real request for help because I'm stumped!

I own a 2000 Ford Explorer Sport 4WD with the 4.0L SOHC. I have to replace the lower thermostat housing due to a massive coolant leak. I am about a third of the way through the project and at a dead stop.

I have moved the air intake hose, the throttle body, and the alternator cable so that I can easily see the housing. The upper housing has been removed already and I have managed to disconnect both sensors.....

My problems start here!

1) I have managed to remove the front most bolts from the lower thermostat housing. The third is a nightmare to reach. I've tried a swivel socket and can't reach it. I have an 8mm self ratcheting wrench but can't seem to budge it because an 8mm wrench is tiny (no leverage). Would a wobble extension help? After pulling the other two bolts off and seeing how long they are vice how far down the bolt the threads are, I have my doubts about soaking it in PB blaster as I doubt it would trickle down far enough...

2) Even when / if I manage to get that bolt out, the housing is in a nightmare spot. I have a vacuum line and the camshaft position sensor wiring to contend with. So let's make this a two part question....

2a) The vacuum line seems like it should be easier to deal with, at least in my mind. There is a T junction with one vacuum line running from the bottom of the T right directly where I need to be working. I started to force that vertical run of vacuum line off the T but stopped because I was moving a lot of stuff and, with the truck being so old, I didn't want to break anything due to old age / brittle plastic. Any thoughts on how to pop this line off or should I just work around it.

2b) The camshaft position sensor wiring..... It's in an nightmare spot because it is going to prevent me from lifting up on the housing to avoid breaking off my three plastic tabs on the bottom of the housing itself. I tried following it up but it gets lost under the intake manifold. I tried following it down but it hugs the front of the motor and disappears. Any thoughts on where / how I can disconnect this thing so that I can get some room?

3) I'm beginning to think that my best bet to tackling this might just be to take off the whole intake manifold. Is that just stupidity or does it have merit? I'm not a mechanic so keep that in mind.... Seems that is just 8 torx bolts that keep it together. How much of a mess am I setting myself up for if I do opt to the intake manifold off?

Thanks in advance!

Andrew

 

[Stick_man]

1. an 8mmm ratcheting wrench worked for me thank g-d. I can't remember if it's possible to apply heat and then try it. is your swivel socket a universal adapter with the 8mm socket on it? is yes forget it. also what size drive are you using? (you need the small one). I remember there was enough room to fit a swivel in there but not enough torque with that universal a I was using.

2a. you can work around it. make no mistake this is a pita repair.

2b. there are 3 sensors that wire harness goes to on the drivers side of the engine. the loom is held in place by a plastic fastener; that is close to those 3 sensors on that side. There is also the same type of plastic fastener on the passengers side. removing just the plastic fasteners gave me enough room but was still a hassle. I didn't bother removing the sensors for more leverage but maybe it would have made things easier.

3. I don't know how much work is really involved with that. Seems like a lot of work.

 

[BubbaFL]

3) I'm beginning to think that my best bet to tackling this might just be to take off the whole intake manifold. Is that just stupidity or does it have merit? I'm not a mechanic so keep that in mind.... Seems that is just 8 torx bolts that keep it together. How much of a mess am I setting myself up for if I do opt to the intake manifold off?

Thanks in advance!

Andrew

The intake manifold is pretty easy to take off. It's held on by a bunch of torx-headed wood screws. Fortunately coolant does not flow through the manifold, and taking it off does not expose the inside of the crank case, so you won't have a big mess to clean up when you take it apart (one of the few smart design decisions by an otherwise retarded engineering team).

Replace the intake manifold o-rings and pcv valve while you're in there.

 

[drdoom]

I removed the intake as well, had to loosen the main PCM harness in order to get the rear screws out. An inch/pounds torque wrench is good for reinstalling the intake. It's a lot of hoses too, I can see the benefits of leaving it in place, but heck I didn't know any better. As for the CKP harness, I took that off too, cleaned it up and replaced the loom & tape. First disconnect from the sensor, then pry the harness retainer off the engine, and very important remember the pathway, then pull it up and set it to the side.

 

[drewmar74]

Thanks for the responses so far....

Stick_Man - Yes, the 8mm socket was attached to a universal joint and, as you said, no - that won't work... Just upgraded the ratcheting socket and I will see if some sort of cheater is a possibility. Also, thanks for the tips on being able to work around the CPS and the vacuum line.

BubbaFL - duly noted re: rings and valve

DrDoom - you may be giving me more credit than I deserve!