Hi there, i own a 1973 XJ6 Series 1, and i'm afraid i'm not too mechanically inclined. Just recently she has developed a vacuum/air sound that seems to be coming from right behind the radio (?) of all things, a constant noise as if a tire is leaking air. When i step on the throttle, the sounds subsides, but when i get up to speed, it comes back. When i shut off the motor, it sounds as if "the tire" has run out of air and fizzles out. (Sorry i can't describe this any better!). If anyone knows what this may be, i would greatly appreciate it! Cheers!

 

It's a vacuum leak no doubt. The Series 3 cars had a vacuum tank on the otherside of the firewall, but same area. I don't think the Series 1 had those. Get under the dash and start chasing vacuum lines.

 

Cheers, Ken, will do. Thanks for your help!