90 NA Auto Supra.. Help Please!

[dcrusupra]

Whens the last time the car had an oil change? Drain the oil and see if it's milky or if it's bubbly coming out. If it's not, then do a compression test. Anything under 120 then you'll need a rebuild regardless of a BHG or not. If it is a BHG get a stock toyota gasket. Unless your going for high boost, in which you'll need to take the whole engine out of the car, send the block and head to a machine shop so they can machine them and lap the block.

If it's not a BHG and your compression is fine, then you may be losing coolant from a leaking hose, the hose at the back of the engine looooves to leak and is a biotch to get to. And if the needle is fluctuating, check the connection on the temp housing. It may be loose.