: 1978 Coupe Deville Climate Control Hissing

PS Coupe Deville
08-11-09, 04:36 PM
This is my first post to the forum. I have a 78 coupe deville with 19K miles that i picked up in May. Ever since i got her, there has been a hissing noise from the climate control panel no matter if position is off or on one of the ac modes. Today, i took off the center panel and removed radio to see if there was a vacuum hose leak. The noise is coming from the vacuum connection where the group of vacuum hoses connect to the ecc. I assume that one should not hear a hissing noise especially when climate control is off. Does anyone know if it is a problem with the control panel itself or is there too much vacumm? Should there be a gasket between the vacuum lines and control? This is my first Caddy so learning as i go along....thanks.

08-11-09, 04:49 PM
You've done everything right so far! No gasket that I can think of. The rubber lines should just seal on their own. The ends of one of those lines might be brittle and not making a good seal. I would take them off one at a time and see what you find, then re-seat them. If the leak persists, it must be internal...