Theo's 928 S4 - GT - GTS website

928 S4/GT/GTS Service List

Here is the official list of required maintenance items for the 928 GTS. The S4 and GT are very similar.

Required annually

Engine: visual inspection for leaks.

Diagnose system: read out fault memory.

Check free travel handbrake lever.

Brake system: visual inspection of brake pads and disks for wear.

Check brake fluid level.

Steering gear visual inspection of bellows for damage.

Track rod points: Check play and dust caps.

Axle joints: visual inspection of dust caps for damage.

Drive shafts: visual inspection of cup seals for leaks and damage.

Exhaust system: visual inspection for leaks and damage, check attachment.

Tires: check condition and pressure (with system tester for RDK equipped cars).

Seals for doors, compartment lids and roof: remove abraded rubber. Apply suitable lubricant.

Check operation of lighting system.

Windshield washer, headlight washer: check fluid level and nozzle setting. In the winter months top up with anti-freeze if necessary.

Battery: check electrolyte and density (for old style open batteries).

All other electrical equipment as well as indicators and warning lights: check operation.

File status report for long term warranty... (after the first 2 years)

Required every 12,000 miles (20.000 km)

Diagnose system: read out fault memory.

Change engine oil and oil filter.

V.belt or Polyrib belt: Check condition and tension.

Toothed belt for camshafts: Check condition and tension
Toothed belt for power steering: Check condition

Toothed belt tensioner: Check oil level.

Change spark plugs (only on vehicles without catalytic converter)

Visual inspection for leaks. Oils and fluids.
Coolant hoses: Check condition.
Radiator: Visual inspection for external fouling.
Coolant: Check level and anti.freeze content.
Air filter: Replace filter element.
Crankcase ventilation: Check tightness of hose connections.
Fuel system: Visual inspection for damage, correct position and tightness of connections.
Intake air system: Check hoses, lines and connections for tightness.
Handbrake: Check free travel of handbrake lever
Brake system: visual inspection of brake pads and disks for wear.

Brake hoses and lines: Visual inspection for damage, correct position and corrosion.

Check brake fluid level.

For 928 with RDK: Visual Inspection of components for Tire Pressure Monitoring System.

Clutch: Check play or final position of pedal.
Throttle valve actuation: Check for ease of movement and full throttle position.
Resonance flap: Check operation.
Steering gear. Visual check of bellows for damage.
Track rod links: Check play and dust caps.
Power steering: Check fluid level.
Axle joints: Visual inspection of dust caps for damage.
Screw connections of suspension adjustment system: Check for tightness front and rear.
Front wheel-bearings Check play.
Manual transmission: axle/drives: Check oil level.
Automatic transmission: Check fluid level.
Drive shafts: Visual inspection of sleeves for leaks and damage.
Exhaust system: Visual inspection for leaks and damage. Check attachment.
Tires: Check condition and pressure (928 with RDK use system taster).
Door hinges: Lubricate.
Check door: lid locks and safety hooks on front lid for tightness and operation.
Hinges for rear lid: Lubricate.
Safety belts: check operation and condition.

Seals for doors, hood and roof: remove abraded rubber, apply suitable lubricant.

Check operation of vehicle fighting.
All headlights: Check setting
Horn: Check operation.
Popup headlights: Lubricate hinges.
Windshield washer, headlight washer: Check fluid level and nozzle settings; In the winter months top up with anti-freeze as necessary.
All other electrical equipment as well as indicator and warning lights: Check operation

Additionally Required every 25.000 miles (40.000 km)

Automatic transmission: change ATF and ATF filter, clean ATF strainer.

Replace fuel filter.

Auxiliary air pump: Replace filter element.

Change spark plugs (only on vehicles with catalytic converter)

Additionally Required every 48.000 miles (80.000 km)

Manual transmission/axle drives: change oil.

Automatic transmission: change oil in axle drive. (differential)

Additionally Required every 60.000 miles (100.000 km)

Replace toothed belt for cam shafts (check tension after 3000-4000 km (2000-2500 miles).

(Theo: it does not mention coolant pump and tensioner/idle rollers. Consensus is that the belt needs replacing every 6 years regardless of mileage)

Required every 2 years

Change brake fluid (also in PSD).
Change cooling.

after 4, 8 and 10 years, thereafter every 2 years

Check airbag system.

Maintenance schedule 1985-95 928.pdf