2001 Malibu fuse and collant question

My Malibu keeps blowing the 20 fuse under the hood which powers the lighter and the powerpoint. I've replaced it about five times now, and it seems to only last a week or so... is there a bigger problem that needs to be fixed?

The intake manifold has a leak again... which we already got replaced for around $400 about two years ago so this time i'm just keeping an eye on the coolant. I've added water twice(there seems to be a small quantity of antifreeze still in it). I bought some dex-cool, but wondered if there is a certian ratio of antifreeze to water that should be in it??

Thanks in advance for any and all advice :)

really depends on where you're at for the mix...but i usually stick to a 50/50 mix. as for the fuse, remove ashtray and see if there is a coin or something bouncing around in there, or any other metal object. do you use the lighter a fair amount, or use the plug for a cell phone charger? if so, try not using for a week or 2 and see if fuse lasts longer. otherwise would warrant checking out more if it realy bothers you.