jdser92

Okay, so I find in my 99 si that the coolant lines are kinda weird. I got the diagram that shows where they all go. I found that on the intake manifold on transmission side there is 2 bungs for coolant. The smaller one was capped off with a cap, that was leaking. The bigger one went to where it was supposed to go, to the thermostat housing. Now looking at my diagram the smaller one is supposed to go the bottom of the throttle. But the bottom of throttle line was going to the bung on ther return neck for the coolant. But that bung on return neck is supposed to go to thermostat as well says the diagram. But my thermostat housing only has 2 bungs, and diagram shows 3. Pictures are better so here is the one bung capped.


Here are the the 2 bungs that I need help with, as of right now I have the small one on intake manifold going to bottom of throttle where it is supposed to go. The small on the return neck on the right by itself has nowhere to go so I capped it. But the manual says it should go to the thermostat housing, but I have no bung for it, seen in next pic.


Thermostat, has 2 bungs, one for heater hose, fine, the other big one is for intake manifold, fine, but doesnt have a 3rd one for the small one from return neck.


Anyone with a 99-00 si, or know about how my b16a2's lines should be, please let me know. Do I have the wrong thermostat housing on there? Is it okay to just leave the one on return neck capped? Just doesnt make sense to me. Thanks for any help.

jdser92

After looking at my manual more, is it possible that I have a D series thermostat housing on there. That is exactly what they look like, with 2 bungs. And the b16a2 has 3 bungs.

JeffBro

Just loop the lines and bypass the throttle body and idle air motor. ANd cap off the extra line.

jdser92

Well I capped off line on the return neck, or the small one farthest to right. I put the small one coming outta head or intake to the throttle like manual says too. Big on outta head is normal from beginning.