Ok, I got the green puddles under the front of my Blazer and the driver side of the core has coolant on the plastic side fins.

I know the metal core of the radiator can be repaired if the leak is in that area. What about the sides where the plastic side pieces are crimped on? If my leak is in this area is the radiator fixable?

 

You have a '98 with regular coolant? Or did you park on an alien?
If you can locate the origin of the leak, drain the rad below that level. Then gob some epoxy or something on there.

 

try a couple of pepper packets from McDonalds or stop leak to see if that fixes your problem. If so, go with it until it gets worse.

Verify its your radiator and not a hose or fitting.

 

I noticed the same thing on my 95. I thought the new drivers side upper hose had worked itself a tiny bit loose after it got hot and cold enough times and was letting a little bit of coolant out. Unfortunately, I checked mine today and its still leaking from the same place, just a pinhole size leak. Ive heard that stop leak can all end up in your heat core and clog it, is this true?

 

I don't know if that is true or not.

I do know that pepper works. A buddy of mine and his family were going on vacation with me and my family. We were about an hour out of town when I noticed his temp gauge was way up there. Not normal, so we stopped in teh nearest town. Grabbd a bite to eat and where talking about it at teh nearest gas station. This elderly gentlemen overhears our conversation and offers up th pepper trick. We figure what the heck do we have to lose, besides the kids had some McDonalds pepper packets left over form lunch. We poured two in the radiator, and sure enough the pepper found the hole, and plugged it. Pepper swells when it gets wet. We topped of the radiator and grabbed two gallons of water and two gallons of anti-freeze just in case. We drove 900 miles round trip on vacation. Then he drove it all summer before his nerves got the best of hima dn he got the radiator fixed. Once it was fixed, he used the water and anti-freeze to fill it up.