It's embarrassing to admit I made this mistake but I thought I would post about it to help people like me. My radiator was leaking so I bought an aftermarket all aluminum radiator. It didn't come with any screws or rubber grommets so I used my old ones. Three of the screws that hold the fan shroud to the radiator were too long. In my hurry to get finished I didn't notice and tried to put them in. At least one screw went in too far and made a hole in the new radiator. I bought new shorter screws and put sealant on them. I hope this works.
Also if you pull hard enough on the old drain petcock it will come all the way out and coolant will pour out. It worked better if I just turned it about 200 degrees counter clockwise and didn't pull. I had several buckets and aluminum pans so very little got on the driveway and I soaked it up with extra large doggy pee pads. I will take the old coolant to a recycling center that accepts hazardous items.

 

Find a good welder and have him Tig that aluminum... save yourself some heartache later.

That really stinks. I've kinda been there. Also, I don't use the petcock, I just pull the lower hose. Makes life a little easier, even if it's a little messier.