what is the deal with this tube? it connects the inlet and outlet....but why? also it's not very tight....it just pulls right out.

That is the thermostat bypass pipe and you need 2 new o-rings on it.

You need the tube to circulate the coolant before the thermostat fully opens. There should be an O-ring on both ends of the tube. Replace the O-rings and then coat both ends with RTV just before installing the head. Dave W

ok thanks guys.....i hope it will seal good enough to withstand the pressures of the water system.....

these are still available new from toyota. the pipe with o rings

davew7 wrote:You need the tube to circulate the coolant before the thermostat fully opens. There should be an O-ring on both ends of the tube. Replace the O-rings and then coat both ends with RTV just before installing the head. Dave W

If the tube and female receivers are cleaned up shouldn't the O rings be enough?

I honestly do not know! The first 4AGE that I rebuilt about 13 yrs ago showed signs of leaking at the o-ring. Who knows how old the O-rings where. Cheap insurance to add a little RTV to the joint [plus O-rings]. I've incorporated the RTV in the last 3 rebuilds. The way I look at it, It's easier to take 2 minutes to seal the joint, Vs pulling the front of the engine to fix a leak after the fact. Dave W