Major leak causing Overheating
 

ok so thanks to those who responded i found out that the cracked part i have IS infact the bigger portion of the thermostat housing. so now i need to get it replaced and get my electric fan hooked up and i'll be up and running once again.

all i can say is...
 

i know that head gaskets are a common problem for supras because of factory torque settings being to low and head gaskets being cheap or old.

replace anything old - water pump/thermostat/head gaskets then try
again. if problem persists i read on another forum that the block may have to be checked. look for discolored oil and bubbles in the antifreeze. also make sure the fan shroud is still on.

anyway, hope this helps some, its the best i know. my supra overheated several years ago, i had no idea why, it was out of the blue, gaskets had went. i replaced them with steel reinforced gaskets and increased the torque settings.

ok cool thanks. i am in the process of getting the parts now.

also
 

i think the reason no one responded is because an overheating supra is like like saying why does it snow in winter, the cubs lose in the playoffs, or wheres the remote?. Everybody who owns a supra with over 100k miles (some less) is destined for a crash course in toyota cooling systems. You can also google "My 19## supra is overheating" to find fellow sufferers of BHG.

Toyota Service Manual
 

Cygnus X1 - Supra

here you'll need this manual too.

MK2 TSRM On-Line