1999 Porsche 911 Cabriolet Part List: Essential Components for Maintenance and Restoration

Whether you're restoring a 1999 Porsche 911 Cabriolet (996 chassis) or simply keeping it on the road, having a reliable part list is critical. This generation marked a major shift with water-cooled engines, and many components are unique to the 996. Below you'll find a categorized breakdown of essential parts, common failure points, and practical advice for sourcing replacements.

Engine Components

The 1999 911 Cabriolet uses the M96.01 or M96.02 engine (3.4L flat-six). Key parts include:

Cylinder Head and Valvetrain

• Cylinder head gaskets: MLS (multi-layer steel) are preferred for longevity.
• Valve cover gaskets: Often leak; replace with OEM Elring or Victor Reinz.
• Timing chain tensioners: Weak point on early 996 engines. Upgrade to IMS-solution chain tensioners.
• IMS bearing: The infamous intermediate shaft bearing. A retrofit kit from LN Engineering or Pelican Parts is highly recommended.

Oil System

• Oil cooler seals: Leak commonly; replace with updated Viton seals.
• Oil pressure switch: Prone to failure; OEM part # 964.606.184.00.
• Oil pan gasket: Use a reusable silicone gasket.

Fuel and Ignition

• Fuel injectors: Bosch EV14 injectors are a direct upgrade.
• Spark plugs: NGK BKR6EQUP (or double-platinum equivalent).
• Ignition coils: Often crack; OEM Bosch or Beru recommended.

Transmission and Drivetrain

The 1999 Cabriolet came with a 6-speed manual (G96) or 5-speed Tiptronic. Parts include:

Manual Transmission

• Clutch kit: Sachs OEM kit (including pressure plate, disc, throwout bearing).
• Flywheel: Dual-mass; replace with a lightweight single-mass if desired.
• Shifter cables: Often wear; buy OEM from Porsche Classic.

Tiptronic Transmission

• Valve body gasket: Use only ZF transmission fluid.
• Transmission mount: Stiffen with a 964 Turbo mount for better feel.

Axles and Differential

• CV joint boots: Many aftermarket options (GKN, EMPI).
• Differential oil: Mobil 1 75W-90 GL-5.

Suspension and Steering

The 996 uses a McPherson strut front and multi-link rear. Common parts:

Struts and Shocks

• Front struts: Bilstein HD (B6) or B8 if lowerd.
• Rear shocks: Same recommendation; you can also get OEM Sachs.
• Springs: Moog or OEM replacement. For lowering, H&R or Eibach.

Control Arms and Bushings

• Front lower control arms: Often have worn ball joints. Replace with OEM Lemförder.
• Rear trailing arms: Bushings are a known weak spot; install polyurethane or monoball.
• Sway bar links: Use adjustable Moog end links.

Steering

• Tie rod ends: OEM from TRW or Lemförder.
• Steering rack: Rebuild kits available; look for leaks at the pinion seal.

Brakes

1999 models had 4-piston calipers (black or red). Parts:

• Brake pads: Pagid RS4-2 street pads; for track use, Pagid RS29.
• Rotors: OEM-style Zimmermann coated; slotted options from StopTech.
• Brake lines: Upgrade to stainless braided (e.g., Goodridge).
• Master cylinder: Often fail internally; use ATE or Bosch.

Exterior and Interior

Body and Trim

• Convertible top motor: Weak point; replace with OEM Pierburg.
• Top hydraulic cylinders: Leak; rebuild kits from Top Hydraulics.
• Door latch: Often sticks; lubricate or replace with OEM VDO.
• Headlight assemblies: Use Valeo or OEM units; avoid cheap aftermarket.

Interior

• Seat recliners: Gear often breaks; replacement from Classic 9 Leather.
• Glove box latch: Known to break; 3D printed replacements available.
• Climate control buttons: Use electronic contact cleaner first; replace if needed.

Electrical System

• Alternator: Bosch 140A or 180A upgrade.
• Starter: Remanufactured Bosch SR441X.
• Battery: AGM style (Odyssey PC680 or equivalent).
• ECU: Often water damaged; seal with silicone after replacement.

Cooling and HVAC

The 996 water cooling system is complex. Key parts:

• Radiators: Often develop leaks at the plastic tanks; use CSF or OEM Valeo.
• Water pump: Replace every 60k miles; use Geba or OEM.
• Expansion tank: Cracks around the neck; upgrade to aluminum (e.g., Fabspeed).
• Heater core: Difficult to replace; flush first.

Exhaust System

• Catalytic converters: 1999 models have two pre-cats and two main cats. Often clog; replace with high-flow cats (e.g., 200-cell).
• Muffler: Rear muffler is known to rust; use OEM or Fabspeed.
• Oxygen sensors: Bosch 13641 for pre-cat; 13642 for post-cat.

Maintenance and Wear Items

• Oil filter: Mann W940/25 or Mahle OC331.
• Air filter: Mann C 39 107/1.
• Cabin filter: Bosch 0 986 306 125.
• Serpentine belt: ContiTech 6PK1780.

Practical Recommendation Section

For a 1999 Porsche 911 Cabriolet, prioritize the IMS bearing and cooling system. Use OEM or high-quality aftermarket parts for critical components like the water pump, radiator, and timing chain tensioners. For suspension, Bilstein shocks and Lemförder control arms offer reliable performance. When sourcing parts, cross-reference part numbers with the original Porsche catalog (available online). Keep a maintenance log and replace fluids annually. If you plan to modify, consider upgrades that address common failure points rather than chasing power. This part list should guide you through most repairs and restorations, helping you enjoy your 996 Cabriolet for years to come.