The exact same thing happened to my 940. I have read that you cannot expect much longer than 8 to 10 years from these radiators. I got closer to 15 years. If you have time & money, just replace it. There is no good fix for this plastic even if you get it repaired somehow- it will leak in 3 or 4 months. The replacement rad can be had for about $150... shop around prices vary. Get the cheap plastic tank radiator and spend a couple of extra bucks to replace hoses if you need to. under $200 for the whole job including coolant. 1 hour in the driveway maybe 2. replacement is good for 10 years and then no head gasket blown because of overheating.