Lot 404: 2004 Porsche 911 Carrera 4S

The 2004 Porsche 996 Carrera 4S has several well-documented engine and transmission issues that potential buyers should be aware of:

ENGINE ISSUES:

1. IMS (Intermediate Shaft) Bearing Failure - This is the most notorious and expensive issue. The IMS bearing can fail catastrophically without warning, typically requiring a complete engine replacement ($15,000-25,000). This affects 996 models from 1997-2005. Many owners proactively replace the IMS bearing as preventive maintenance ($2,500-4,000).

2. Air-Oil Separator (AOS) Failure - Very common issue where the AOS fails and allows oil to enter the intake manifold, causing rough idling, misfires, reduced power, and oil leaks. Replacement cost is typically $800-1,200.

3. Rear Main Seal (RMS) Leaks - Common oil leak from the rear main seal, usually requiring transmission removal to repair ($1,000-2,000).

4. Oil Cooler Issues - As Porsche’s first water-cooled 911, the 996 can experience oil cooler problems leading to oil/coolant mixing.

TRANSMISSION ISSUES:

1. Second Gear Pop-Out - The G96 manual transmission commonly experiences second gear pop-out due to incorrect factory shimming. This causes the shift sleeve’s teeth to wear prematurely. Repair requires transmission rebuild ($3,000-5,000).

2. Synchro Wear - High-performance manual transmission that can experience synchro wear, especially if not properly maintained with regular fluid changes.

GOOD NEWS: Looking at this specific vehicle’s service records, I can see the rear main seal was already replaced and transmission fluid was serviced, which addresses two of these concerns proactively. The 27 service records suggest meticulous maintenance, which is crucial for 996 reliability.

Bottom Line: While these issues sound scary, well-maintained 996s can be reliable. The key is finding one with documented maintenance history (like this one) and budgeting for preventive IMS bearing replacement if it hasn’t been done yet.

Would you like me to help you find similar 996 Carrera 4S vehicles, or do you have questions about any specific maintenance items on this car?