The rad. i picked up at the yard has some rust in it and it was reccomended to me to put some CLR in the rad and fill it with water and let it sit. good or bad idea??

I've never had any great success using a flushing product of any kind. Except for taking it in to a radiator shop, back-flushing with pure water does the best job of removing rust and scale. I just cleaned the radiator on my truck by turning it upside down and running a high pressure stream of water through it. Lots and lots of junk came out.

CLR is very mild compared to some products designed to clean radiators.

thanks man

I'll give my secret away, get a "miracle grow" garden sprayer for fertilizer, unscrew and discard the nozzle, you now have the ability to attach a common garden hose (found a 4ft. one at my h/store), which attaches to your flushing tee. Other inlet attaches via common garden hose to your water source. Go to a paint store and get some TSP (tri-sodium-phosphate), do not get the crap sold at the grocery or drug store. Load the container, start the flow, fire the motor up-turn on your heater also and have at it, refill with TSP as needed. When done fill/flush with baking soda to nutralize the TSP. Do not try CLR, I did once and it unsoldered the top tank! Have used this method for over 15 years now, including one flushing session which took over 5 hrs before the h20 ran clear!

_________________
Troops on the battlefield have a far better view of the battle then the generals who lead them