POLL: 3.8L engines with Retro/Classic Auto Air a/c

I’ve begun the process of installing a Classic Auto Air (formerly RetroAir) a/c system on my 1964 3.8L E-Type FHC, and I have a couple of questions about other 3.8L owners’ experiences with the drive belt(s). I would think that the purely performance-related aspects of the kit should be the same across all 3.8L engines, thus my query here (as well as on the E-Type and Saloon forums).

  1. Did you do a 1-belt installation or a 2-belt installation?
  2. How many miles have you gone since installing the a/c system?
  3. Have you experienced any belt issues?

I’m running this poll because I’ve been told by a certified Jaguar oracle (who shall remain nameless here) that RetroAir’s 1-belt solution is flawed because the belt runs backside down over an idler and he’s seen more than one example of the belt failing at under 1500 miles. I want to see if that is a widely-shared experience. This should be useful to future 3.8L owners considering how to proceed.

Thanks in advance for sharing your experience.


If we’re talking about a V-belt with a 3L, 4L or 5L shape, then take it from a degreed licensed professional engineer with my full name, that it is indeed a dumb idea to run a v-belt backside down over an idler.

Backside idlers are used with flat belts. They sometimes have ribs on both sides. This is from a 2000 S-Type which has an idler.