The GTM Supercar Build Log

AC is Functional!

After putting 1700 miles on the odometer I figured it was time to see if I could fix the AC leak before summer was over. I took the GTM to the local shop that tried charging the AC in my garage last summer with the hope that they could use their ‘sniffer’ tool to find out where the AC leak(s) were. Fortunately, the tech was able to locate the leak in less than 5 minutes. The leak was at the low side service port connector to the AC accumulator/dryer. I had my fingers crossed that this would be where the leak would be, as many other builders that have had AC leaks had their leaks at the same connector.

The cause of the leak was an insufficient o-ring. The o-ring supplied with the vintage air kit is one size too small. Any builders out there that haven’t gotten this far yet – make sure to check that o-ring. With the new o-ring in place the system held vacuum and charged successfully. I got in the GTM and cranked the AC and was greeted to a faceful of 2 years worth of dust, but it worked! This was a great relief, seeing the AC fire up and work properly.

When I was tuning my motor last year to get it running properly I had set my “AC target idle RPM” to 1100 and the car seems very happy at that RPM with the AC running. Took it out for a 35 mile drive in 80 degree weather and the car never got any warmer than it would have when the AC was not working. At stops it actually runs/idles smoother with the AC on.

Cliffs: AC works great and keeps the car nice and cool. Check your accumulator low-side service port connector o-ring!

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