Re: Leaking coolant unusual gasket part number 1990 JDM MR2 Turbo?
Those surfaces may be a little eroded when it's dismantled but usually perfectly salvageable.
Just carefully clean them and then use a sensor safe silicone such as Loctite SI 5699 or equivalent.
For many years I've used Permatex Aviation Gasket goop successfully.
Torque the two bolts evenly and don't over torque them.
Same with the upper housing of that coolant tree. It is one of the worst pieces of design I have seen.
It contains an "O" ring that is available from Toyota dealers.
I use Aviation Gasket goo as well as a new "O" ring any time it's disturbed. Disgraceful design.
Do Not Over Torque !!!