Overheating....head gasket i believe

[cre]

It's fine at 75+

[Killa B]

"If you had both block and head cut then it's unlikely that the issue is that they weren't flat... at least not flat enough for a composite HG. For one reason or another a coolant jacket AND a bore jacket are not sealing... This is a bit much for a defect to be the culprit. I think that you're most likely dealing with a head that isn't all the way down. There are a couple reasons this could happen; The most common is that the lower, rear timing plate which bolts to the block was not attached to the block when it was machined. These need to be together when machined ad the HG and head lie on top of BOTH. If the timing plate isn't cut the head sits high there, you loose oil out the sides at the very front (how soon this starts happening depends on the offset) and you get coolant passages that are open enough to expel coolant and allow combustion gases in. If the timing plate is cut more than the block you'll find oil leaking into the timing belt area. Also, if you forgot to put the RTV in the specified locations before placing the HG on top of the block you'll get an oil leak out the front sides too."

where are the specified locations i used ALLDATA to do my rebuild and dont recall it saying anything about RTV i thought you werent supposed to use RTV on a HG? What kind should i use just regular gasket maker?

[cre]

I don't have ALLDATA any more so I'll assume it's incomplete... It's not the first time. No, you don't use RTV as a HG dressing. It may be required to seal unions if specified. In this case it's placed at the union of the rear, lower timing belt housing the block and the HG.

http://www.cygnusx1.net/Supra/Librar...aspx?S=EM&P=55

I don't know why, but there is sufficient pressure there to ensure it will leak sooner or later if the RTV/packing isn't used (ask me how I know).

It's also supposed to be applied here: http://www.cygnusx1.net/Supra/Librar...aspx?S=EM&P=52