Okay so I'm taking apart my engine to replace my two knock sensors and I got where I needed to be. However, I found water sitting on top of the engine block under the lower intake manifold. If anyone could help explain why this is here that be great! 1999 Toyota 4Runner V6 3.4L

 

Here's a zoomed out image also

 

Check that water bypass tube. Sometimes they get pin holes but most often the sealant where it attaches to the block fails. There is no gasket there, just a small bead of FIPG/RTV.

You are placing the knock sensor wire too? They get very brittle with heat. What leads you to replacing the knock sensors?

 

Well my check engine light came on sometime ago and I'm finally get to it. But yeah I've got two new sensors, harness, and gaskets to replace them. But the water bypass tube. Is that the metal rod running in between the valves?

 

Also found water in these ports. I don't know if that changes from where the water is coming from.

 

Yes, it's the tube between the heads.

 

So came upon another issue. I got everything back together and found out that a leak was coming from my fuel injector. And I found this piece laying around my engine. So I tried fitting it in their assuming this would be the cause of the leak and it wasn't fitting very well. So if anyone knows what this goes to please let me know!