That seems to be a common problem - my radiator did exactly the same thing about 18 months ago.
I had a spare radiator to swap in - but depending on where the crack is and how long it is, there may be some kind of sealant that you can apply to it. Being plastic however, I am not sure how well this would work.
As far as I know, the SVX radiator is unique - and I was once quoted over $1500 by Subaru for a new one!!!!
I have seen several SVXs with custom radiators with a metal top tank - as that seems to be the location where the plastic ones will crack.
My radiator cracked on the top tank, directly in front of the radiator cap.
For a permanent fix, you will probably need to source a spare radiator, or get a custom one made up.
Jason.
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1992 Charcoal Grey SVX - 165,000km
1992 Ruby Red SVX - 165,000km
....now with sequential VIN numbers!
1986 Holden (Isuzu) Piazza Turbo - 225,000km
1993 Mercedes W140 S500 Coupe - 153,000km
1990 Mercedes W124 300D - 313,000km
EG33 + 4EAT + VTD AWD = SVX
