Jen,
After you chill, go back and look at all the rubber junctions...wiggle them a bit and I'll bet you find one that's cracked.

FWIW, I keep the a few of the three and four junction ones 'in inventory' here at Area 51. Having two 20+ yo vechicles that rely on vacuum means I'm always sticking a new one on somewhere.

Next time you order parts add a few to the order.

__________________
Never a dull moment at Berry Hill Farm.