993 Faq Frequently Asked Questions about the Porsche 1994-1997 993


Defective A/C ballast resitor

Filed under: Air Conditioning — Jeff 993TT @ 7:34 pm

Both the oil cooler and A/C condensor use the same resistor that has been found defective in recent TSB. A symptom of a defective A/C resistor would be speed fan that would cycle on and off at 15 to 20 second increments when you have the A/C turned on.

To check for the proper operation of both the oil cooler and A/C resistors, refer to this page: 964/993 Oil Cooler Fan Operation & Troubleshooting

Here is more information on changing the resistor: Subject: AC Ballast Resistor Replacement

The replacement resistor can be ordered from the usual online sources.


How much HP does the A/C system use?

Filed under: Air Conditioning — Jeff 993TT @ 7:25 pm

Based on dyno tests, a 10-12 HP loss when the compressor clutch is engaged is noticed. Belt tension accounts for some variations here.

The ECU doesn’t change timing or fueling when the compressor is running, only hot idle speed.



How much does weight can I save by removing the A/C?

Filed under: Air Conditioning — Jeff 993TT @ 9:41 am

The compressor in the engine compartment alone was 15 – 20 pounds. In addition, I removed all the lines, a tank on the inside wheel well and the condenser that is located between the two front fans. I estimated about 5 pounds for the coolant.


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