Coolant Line Leak - Help Identifying Part #

With the car parked and cooled down, there should be no difficulty. You won't even loose much coolant from that particular hose, which is only used for circulating bubbles back to the top of the reservoir to keep them out of circulation.

I noticed in your photos that there is a hose clamp on each of the two hoses coming to that fitting from amidships, but no clamp on the hose that leads from it to the reservoir.

That's confirmed in the diagram: there isn't a clamp used there. That's because the little Y fitting and that last leg of hose are sold as a single part (16264D in the picture). They probably permanently stick that hose on that end of the fitting. Maybe somebody took yours off for some reason?



For some reason, the US catalog shows two different part numbers possible for 16264D:


1626437060 - Hose, water by-pass, no. 2. Engine - Genuine Toyota Part


1626437080 - Hose, water by-pass, no. 2. Engine - Genuine Toyota Part


I can't see any indication of how one is different from the other, but one is six dollars more.

I am not sure if the part numbers would be identical in "UTC" though.

 

Yeah a few years back there was some (inconclusive) discussion about why there's no clamp there. You might be right, that there's a bonding agent of some sort in the connection.