The 91 244 that I recently bought has a newer radiator in it. I thought that was great, but upon closer inspection, I am realizing that the radiator is a generic piece of crap, probably an autozone special or something like that.

Anyway, to my point. It wasn't leaking, but during my front seal/timing belt replacement, I somehow got it leaking. There is an approx. 1/2 inch hole on the passenger side, upper part of the tank. It has some kind of thumbscrew plug in it (the more you tighten it down, the more it expands?)Must be so it will fit other cars as well. I tightened it down some more, but it is still leaking.

Is there something better that I can use in that hole, so that I don't get any surprises on long trips. In other words, is there a more permanent better quality plug that won't fail or blow out under pressure?