4.0 head removal question

[2016 4Runner SR5]

OK so noob to the 4.0 Picked up a 2005 with a broken timing chain and I plan to pull the heads for rebuild. Coolant passage is kicking my ass. On the back side of each head, there is a U shaped pipe that connects the 2 heads together. I removed the 4 10MM bolts, 2 on each side without an issue. There is 1 more bolt on each side, I cant see it and I can't figure out WTF it is. Anyone have any idea what type of bolt it is?

 

[waypoint]

I haven't worked back there, but it looks like a pair of triangular assemblies as shown below.

Check page 11 of the shop manual posted here and you'll see them:

http://www.customtacos.com/tech.old/files/05FSM/data/ileaf/06toyrm/06toypdf/06rmsrc/rm2006ta/007017.pdf

The gaskets may give an idea of the 3rd bolt location:

https://www.rockauto.com/en/catalog/toyota,2005,4runner,4.0l+v6,1431016,cooling+system,thermostat+/+thermostat+housing+/+water+outlet+seal,2136

 

[2016 4Runner SR5]

I'm able to find and feel the bolt location, just nothing fits it. No socket, no allen socket, no torx socket. I'm literally ready to pull this engine out and do with work on an engine stand lol. Would make life so much easier since i'm going so deep into it anyway. May just do that and drop the oil pan also. Swap the rear main seal, new oil pan gasket, clean the pan out well even though it looks spotless already. Then I questions myself as to why not just have the whole engine rebuilt...………..

 

[AuSeeker]

I'm able to find and feel the bolt location, just nothing fits it. No socket, no allen socket, no torx socket. I'm literally ready to pull this engine out and do with work on an engine stand lol. Would make life so much easier since i'm going so deep into it anyway. May just do that and drop the oil pan also. Swap the rear main seal, new oil pan gasket, clean the pan out well even though it looks spotless already. Then I questions myself as to why not just have the whole engine rebuilt...………..

Are you not able to stick a mechanic's mirror or any mirror, or even maybe your phone camera back there to see better/take a photo what you're up against?

 

[2016 4Runner SR5]

Unfortunately no because it's so close to the firewall that a phone cam picture would not show it clearly. I tried a mirror but failed lol i'll try that method again. There's barely room to get your hand in there let alone anything else.