C Frank: Why did my 81 suburban developed a coolant leak when I changed it from green coolant to orange coolant?
Toxguard: Several different things could have contributed to your coolant leak.
First, you may have already had a leak but it was being blocked by mineral deposits. The lowered pH of the extended life coolant may have helped free the mineral deposits. Also certain types of extended life coolant have less surface tension allowing it to get into smaller places. Finally you have an 81 suburban how many miles are on that vehicle? Some of the parts of the old girl might just be getting old.