Thermostat Problems

[1jzrhd]

So here's my problem. I'm driving down the highway when I notice my temp gauge jumps. I get out and see that my rad fluid is fine, but my engine coolant is bubbling. So I walk to the nearest farm and get some coolant for it. I get my car 5 km down the road to the nearest town with the coolant filled and it is bubbling again. So the dilemma is that either the thermostat is stuck closed or theres something else wrong. I know its not my rad or any engine troubles cause my car was running fine. Any advice or comments on what else it could be? Would a 2jz thermostat work in a 1jz without much modification?
Thanks in advance with this as I know you guys are very knowledgable.

 

[JonnyRedline]

1jz thermo = 2jz thermo

try replacing it and burb the system when finished to make sure its functioning properly...if it doesnt change anything, yer rad is shot

 

[JCP]

well depending on the temp in your area you can just take the thermo out until you get some money... thermo just restricts the coolant flow.. now if the general temp in your area is cold... or it gets cold @ night or is about to turn cold... then i wouldnt do it.. Anyway.. if its summer type temps 70-80F+ then it will actually cool better . its up to you though.. I am not a pro and take no responsibility for what ever may happen. GL!