Top right corner corner of radiator leaks small amouts of coolant that run down the side of the radiator and drip down to the ground after driving my 2001 kia rio. i thought it was the cap so i repla

SOURCE: Where is 2003 Ford Focus ZTW radiator cap?

If your resevoir cap is a screw on cap it is probably the only cap you have most cars nowadays pressurize the resevoir and this is where you add coolant and dont have a rad cap

SOURCE: coolant leak on 2004 grand cherokee 4.0

might be the thermostat housing to as its right above the water pump. the best bet would be to pressure test the cooling system and inspect to see where its coming from

SOURCE: leaking radiator in '96 Ford Explorer

Usually once a radaitor starts leaking you should replace it since it is a pressurized system and could cause overheating.

SOURCE: I have a small leak of coolant at the top of the

Is the plastic part of the radiator? The radiator builds pressure so sealer may only work temporarily at best. Or are you talking about the (yellow) plastic surge tank that also holds coolant? SOME of these are also under pressure.

If you need to drive somewhere and your seal fails, you will get stuck, and it might also damage your engine.

Get a new radiator or surge tank or weld your plastic (yes, plastic can be welded!) if you care about getting stuck.

Hope this helps.

SOURCE: coolant leak --redoing my former question---!

I think you are trying to say that the plastic side tank is leaking. Likely on the seam where it joins the metal part of the radiator? I haven't seen too many sealers that work on those, but the old "standby" two tablespoons of black pepper (no kidding) sometimes will, unless the leak is a large one. There are some sealers on the market that claim they can plug just about any leak, but I have never tried them. (just too many)
The best way to do that repair is by changing the radiator, either with one from a scrapyard or new.
I used pepper in my own two years ago and am still waiting for it to begin leaking. (and heat works fine) Just make sure to drive five or ten miles after adding it or it will clump up and not help at all.

Good luck..