I lost my air bleeder cap so I plugged it with the bottom of a lightbulb (the brass threaded part) since I figured my car was rendered useless untill I magically found an air bleeder cap somewhere in maine. Anyway today I installed the DIY BOV and I was driving it hard in the dark. (I had driven it many times before this without any ill effects) The "add coolant" light kept coming on then going off when I accelerated. When I stopped I noticed a shitload of smoke coming from under the hood. I opened er up and the make-shift cap had blown off and boiling coolant was shooting all over my air filter and engine bay. What can I use to plug this? Do you think I can just buy a brass or steel threaded plug like 1/4" or so that will fit in there? or do I need to get an OEM one?

 

You can get a replacement plug from your local Mazda dealer, Mazdatrix.com , or at your local generic auto parts store (Autozone, Discount Auto Parts, etc.). If you can, get the wing-nut type of plug instead of the phillips head type. Note that the bleeder plug and drain plug can be interchanged, so you can also ask for a "dran plug" if the store is out of "bleeder plugs".