Installed new radiator in 98 SC2, started leaking after two months. Installed another, everything was fine for about 1 1/2 months and that also began to leak. Radiator shop says I probably have a bad head gasket. There was no loss of coolant until it began to leak externally. I have let it run for 1/2 hr with no signs of bubbling back through the reserve tank. Any ideas?

 

Are you you're buying el-cheapo radiators? The el-cheapo replacement for these cars is known for exactly what you describe. Also, not installing them correctly (incorrect mounting + vibrations = cracks in side reservoirs).

What are you using for coolant (pink/orange or green?)

Call a local saturn dealer's part's dept and ask them what brand they recommend -- besides the saturn oem......

Why anyone would tell you you have a bad head gasket when your coolant is not disappearing is beyond me. The only exception to this is if the coolant and oil are mixing, making your coolant look like a milkshake. I suppose such a mix could quickly damage the inside of your radiator......

 

+1 on possibly the cheap radiator. the other thing maybe is if its an auto trans and the TAM mount is bad enough could also be causing it if around the tranny lines