The other day, the air conditioning on our air-cooled Porsche 911 (964 model) stopped working, and my husband wrote an article about it. Please take a look if you’re interested.

Air Conditioning on the Air-Cooled Porsche

Lately, I’ve been rotating through the Porsches, switching which one I drive each week.

As summer approached and the temperatures rose significantly, I decided to take the 964 out for a spin after a while.
Starting the engine in the parking lot, it fired up quickly and smoothly. Thanks to the Megalife battery, the engine wakes up instantly.

As usual, I switched the air conditioner ON, and I could faintly hear the compressor’s “shoo” sound. I expected cool air to start blowing, but the “shoo” sound never stopped, and only lukewarm air came out. This is the third year since I bought it, and the AC had been relatively effective, so I immediately noticed something was wrong.

After driving for a while, sometimes the air felt a bit cooler than the outside temperature, but it was never cold enough to cool the cabin properly. Most likely, the air conditioning gas is running low, which is a common issue with air-cooled Porsches.

Refilling the Air Conditioning Gas

I promptly contacted our trusted mechanic, Beeforce, and scheduled an AC inspection along with an oil change.

From our conversation, I learned that for Porsches of this era, even if there’s no obvious leak, the AC gas will inevitably decrease little by little over time. A common leak point is often around the evaporator piping.

To find out whether there was an actual leak or just natural depletion, we decided to refill the AC gas and add a fluorescent dye to pinpoint any leak locations.

So this summer, I’ll keep an eye on it and keep driving as is. If the AC gas runs out quickly again, we’ll use the dye to identify the leak.

How Does the Air Conditioning Perform After Refilling?

After also having the oil and filter changed, the engine felt even smoother when I started driving. The last oil change was in November, so it had been about 4,000 km and 8 months since the previous one. Modern cars don’t show much difference after an oil change, but with older cars, the effect is much more noticeable.

After driving for a bit, the “shoo” sound quickly stopped, and cool air properly blew from the vents. It can comfortably cool the cabin up to around 30°C. This is very comfortable.

By the way, many people don’t really understand how to use the AC levers on this model. Moving the upper lever to the right maximizes airflow from the gap between the front windshield and dashboard, while moving it to the left directs airflow from the dashboard vents. The lower lever controls footwell airflow—left is minimum, right is maximum.

So, basically, it’s best to keep both levers to the left during summer driving.

Lately, I rarely see air-cooled Porsches around the neighborhood. Perhaps because it’s summer and prices have surged, more owners are carefully storing them away. But I don’t care about that—I want to drive mine hard and often. Now that the AC is working well again, I’m going to enjoy the luxury of using my air-cooled Porsche as a daily driver.