Knock sensors and harness question

I'm doing a knock sensor and harness replacement and have questions about the thermostat housing or whatever that cast aluminum piece is at the front end of the coolant pipe that you have to remove to pull the coolant pipe out. Does anyone have a picture of that piece removed so I can see the bolt pattern? Also does it have a gasket that needs replacing or do you use some kind of form-a-gasket compound for it? I've searched the forum high and low and can't find any specific info for removing and replacing that piece.

 

Looks like it just uses O-Rings, you might run into it having some gray FIPG on it, replace it with FIPG-103 if so.

 

Thank you very much! Excellent information right here!

 

The 4.0 is also used on the FJ.
A little Google-fu turned up This

Hope it helps.

 

Careful I know some years (if not all) of the FJ use the dual VVT-i motor not everything is the same or even compatible.

 

That is true. But I doubt there is a difference in the water by pass.

I believe the 09+ FJ was Dual VVTI

 

I just check my manual.
The only difference is that the Tacoma manual says connect the the hoses to the oil cooler is applicable.
Where as the FJ manual doesn’t say anything about it.

 

Oh man this is exactly what I needed! Much appreciated! Shows that there are 3 more bolts underneath that I can't even see from up top

 

That bypass pipe between the heads is not coming out unless a cylinder head is removed. Looks simple on the parts diagram there but it is bolted down in the rear passenger side cylinder head.

 

This is correct. The FSM and corresponding service pricing has the head(s) come off to do this service, hence the reason the dealer quotes between $2300-4000 for this service.

I just successfully replaced the harness on my buddy's 2006. The driver side connector wires were chewed completely through. I bear-hugged the top of the motor for the better part of an afternoon playing Pick Up Sticks with an assortment of pointy things including picks, screw drivers and bamboo chopsticks (no joke) but was able to successfully remove the entire harness and replace with a new one. Not a fun process but better than removing the heads!

Good luck!

 

I've got it broke down to this point but had to quit tonight because my work lamp burned out. The larger pipe will definitely come out. It has some play in it and it moves around enough to know that it will slide out of that rear casting. Going to get some curved jaw vice grips tomorrow to get a better hold on it.

 

I'm super interested to see what you come up with, so please keep us posted.

After working on Toyota trucks my whole adult life and usually always being impressed with the thoughtful engineering towards ease of maintenance, I couldn't believe Toyota would design the crossover pipe not more easily removed. The crossover pipe in my 5VZ-FE needed resealing as it aged, which was a common problem, so figured they did away with the coolant pipe unions there forgoing ease of maintenance for long-term reliability. Definitely interested to see what you come up with.

 

Just revisiting the diagram. How easy are these three bolts to remove? I don't remember having easy access to them.

 

You have to saw cut the front one and I believe the rear two are attached only to the smaller diameter pipe. I am following a YouTube tutorial video and I believe that's correct. I'll post the vid later today.

 

Here is the video. The pertinent part starts around 14 minutes in.

Watch "How to replace Knock Sensor 2003-2009 Toyota 4Runner" on YouTube
https://youtu.be/hwVcU7mkap4

 

^^^^Man. Wish I had found this video before taking this on. That would have saved some time, although I don't think my buddy would have approved of the bracket cut method. Thanks for posting, though, Partychief.

Regarding the video, and for posterity, I didn't bother unbolting and moving the fuel rails or even disconnecting the fuel lines from the manifold. Plenty of slack in the fuel lines to just swing it all out of the way.

On another note, anyone else pucker before he stuffed towels into the intake ports while unbolting those 10mm crossover pipe bolts?

 

I finally got it out. The hardest part was pulling the cab end of the pipe out of that cast housing in the back of the block. I had to rig up a homemade puller out of a twisted rope and a couple of pieces of stiff rebar braced against the frame.

 

Bumping to ask for additional info. The knock sensor harness runs down the valley and bends down into the gap between the firewall and back of the block. I'm looking for the connector to unclip the old harness and attach the new one. I've looked from above, through the fender well and crawled underneath and looked up looking for that clip and can't see it. Does it go through a hole in the firewall?

 

In that diagram are those Toyota part numbers? I've tried googling a few of them and also searching Amazon to order some new ones and coming up empty handed.