Coolant gone, no leak visible??

First try to identify exactly where the leak is. With the upper 2 sections of the intake off there should be more room back there. There is a hose connected to the tube, it could also be the source. Only a couple inches between the two. Feel around, use a mirror, dislocate your wrist, what ever it takes. Or take the approach that you are this far in, so might as well pull the lower intake and replace the short knock sensor harness. Not kidding about the deterioration of that harness.
At your stage of the game, to get to the bypass tube just pull the lower intake. No need to remove the t-belt.

Coolant will first be seen at the bottom of the plate seen just below the exhaust crossover. Of course the pic also shows a leaking core/freeze plug.

 

I just realized there's a hose back there, from examining the FSM. I will look at that hose real hard. The weird thing is the guy pressure-tested it twice. I dunno why he didn't already find it. ??

So, you can get the lower intake off without removing the timing belt? Glad you told me that; I was probably gonna throw in the towel if "special tools" and timing belt removal were gonna be involved...

Thanks, man. I'll report back.

 

Yes. Someone else mentioned that there is no o-ring and it just uses Toyota RTV Black. I used the generic high temp black RTV and it worked fine.
Unfortunately the whole intake manifold has to come off to get at it.

 

I'm seeing that.

The leak does not appear to be coming from the hose at the aft end of the pipe.

 

this is what i am concerned is happening on my 4Runner, thought i had it whipped when i replaced the coolant hoses at the heater control valve ( original on a 20 yo truck) they were leaking from the ends and dripping down onto the exhaust crossover which it just under by about 8"

i can only smell coolant after truck has been driven and back window is open. or after its been parked after driving and hot. Nothing in exhaust, no puffs of smells on start up, though i did do head gaskets 3 years ago. loosing coolant slowly, less so now that its cooler outside.

 

Sorry if I miss quoted having to take the timing belt off I have owned alot if Toyota's over the years so must be 3.0 u have to do that.
But yes get a new knock sensor harness.

 

I would bet that timing belt removal is "recommended", or even directed in the FSM.

 

Just went through this myself, '06, 4.0

Mine was a tiny crack in the thermostat housing, expanded
and contracted, leak... No leak.

Not a constant, never saw anything on the ground.

Pressure test showed it

 

So, moving on with intake removal, to repair the leaking water bypass pipe and replace the knock sensor harness, as recommended.

Question: How to release this plug, at the rear of the lower intake? View is from the driver's side.

 

Disregard; it just pulls off, as opposed to separating.

 

Definitely wet there in the valley.

 

Question for anyone listening: What exactly is the purpose of the water bypass pipe, anyway? (Aside from the obvious, "to bypass water"!) Does it have to do with the heater?

 

Allows heated coolant to circulate thru heater core so you get heat before T-stat opens

 

Okay then. Thanks.

It sure makes a mess when the sealant fails...

 

NOW I have a leak visible. Now that I've resealed the water bypass pipe, replaced the intake gaskets, rebuilt the valve covers with their multiple gaskets, and buttoned every thing back up. NOW, my driver's side upper end has seepage of coolant as seen below...

Help, Tacoma World.

 

That looks like oil.
If u think it's coming out of the valve cover it is oil

 

I'll look harder. I know that coolant cannot come out of the valve cover. Also, looking more at the photo, I see what looks like new motor oil around the valve cover bolt on the right, at about 7 o'clock from the bolt.