i have a '66 coupe, 302 and a rebuilt c4 (10k miles on it or so). everything runs great, however, if i don't drive the car for 10-14 days (i work from home so not uncommon) the c4 will dump fluid on the driveway. this is ONLY when the car hasn't been driven or moved in about ~2 weeks. what would cause this? it never leaks a single drop when it's driven regularly, and i've crawled under to double check. any thoughts?