Porsche 928: Common Problems, Repair Costs & Specs

Written by Zach, an independent mechanic in the Pacific Northwest. Last reviewed September 2026. Spot a mistake? Tell me.

Common Issues

What goes wrong on the 928, how to spot it, and what it costs to fix.

Timing Belt Failure

Advanced

Symptoms: Engine won't start, catastrophic engine noise, bent valves, visible belt damage through inspection hole

The 928's V8 is an interference engine, and one long belt drives both camshafts and the water pump around a path of rollers and a tensioner. When it fails, the valves meet the pistons. The job is big and the parts list is long, but it's the difference between owning a 928 and owning a parts car.

Estimated Repair Costs

DIY $300–600

Shop $1,500–3,000

A major job. Replace the rollers, tensioner, and water pump too.

Common Fixes

Replace timing belt every 30,000-40,000 miles or 4 years
Replace all timing belt rollers and tensioner
Replace water pump at the same time
Replace front camshaft and crankshaft seals
Inspect and replace belt cover gaskets
Use only high-quality oem or premium belts
Budget 8-12 hours labor at a specialist shop

Common Parts

Part	Part Number	Typical price
Timing Belt	928.105.151.02	$80–150
Roller Set	Varies	$200–400
Water Pump	928.106.032.04	$150–250
Tensioner	928.105.240.06	$100–200

Sources: Rennlist, 928 Specialists

Cam Tower Gasket and Oil Leaks

Advanced

Symptoms: Oil leaks at top of engine, burning oil smell, oil on exhaust manifolds, low oil level, smoke from engine bay

Oil leaks are part of 928 life, and the cam covers are the main source. The gaskets on top of each bank harden with heat and age and leak onto the exhaust manifolds, which you'll smell before you see. Reseal them, and look at the other gaskets while you're in there.

Estimated Repair Costs

DIY $200–400

Shop $600–1,200

It all leaks eventually. Budget for a full reseal.

Common Fixes

Replace cam tower gaskets with updated Porsche gaskets
Replace valve cover gaskets at the same time
Inspect and replace cylinder head gaskets if leaking
Replace rear main seal if leaking (requires transmission removal)
Replace oil pan gasket if leaking
Replace all oil cooler lines and seals

Common Parts

Part	Part Number	Typical price
Cam Tower Gasket Set	928.105.195.03	$80–150
Valve Cover Gasket Set	928.105.933.00	$50–100

Sources: Rennlist, 928 International

Engine Wiring Harness Deterioration

Moderate

Symptoms: Random misfires, check engine light, running issues, no-start conditions, sensors not reading correctly

The engine harness runs through the heat in the valley of the V8, and its insulation goes brittle and cracks. That causes intermittent running faults that are hard to trace, especially on the S4 and later cars with more complex engine management. Rebuilt harnesses are available and often the real fix.

Estimated Repair Costs

DIY $200–800

Shop $1,000–3,000

Rebuilt harnesses are available.

Common Fixes

Inspect harness for cracked or brittle insulation
Rewrap harness with proper heat-resistant tape or conduit
Repair individual broken wires with proper soldering
Replace entire engine wiring harness (rebuilt available)
Add heat shielding to protect new harness
Clean and protect all electrical connectors

Common Parts

Part	Part Number	Typical price
Engine Harness (Rebuilt)	Varies	$500–1,500
Harness Repair Kit	Varies	$50–150

Sources: 928 Specialists, Rennlist

Automatic Transmission Issues

Advanced

Symptoms: Harsh shifting, slipping, delayed engagement, no movement in gear, fluid leaks, overheating warning

Most 928s were sold as automatics, using Mercedes-Benz sourced gearboxes: a three-speed in early cars and a four-speed after that. They're tough, but they need fluid and filter service, and 30-plus years brings worn bands, tired mounts, and harsh or slipping shifts.

Estimated Repair Costs

DIY $100–200

Shop $300–2,000+

Fluid and filter are DIY. Rebuilds are a shop job.

Common Fixes

Regular fluid and filter changes (every 30,000 miles)
Flush transmission cooler and lines
Replace transmission cooler if clogged or leaking
Rebuild or replace valve body for shift quality issues
Replace torque converter if shuddering
Full transmission rebuild for severe issues

Common Parts

Part	Part Number	Typical price
Transmission Fluid, Dexron VI (8L)	Varies	$60–100
Trans Filter	928.325.901.00	$30–60

Sources: Rennlist, 928 International

Cooling System Failures

Advanced

Symptoms: Overheating, coolant leaks, white smoke from tailpipe, heater not working, temperature gauge fluctuation

A 928 makes a lot of heat, and the cooling system has to keep up. The water pump is driven by the timing belt and should be replaced with it. Radiator end tanks crack with age, and a V8 this complex doesn't take overheating well.

Estimated Repair Costs

DIY $300–600

Shop $800–1,500

Service the whole system.

Common Fixes

Replace water pump with every timing belt service
Replace thermostat with oem temperature rating
Replace radiator if plastic tanks cracking or leaking
Replace all coolant hoses (including heater hoses)
Flush cooling system and use proper coolant
Check and clean electric cooling fan operation

Common Parts

Part	Part Number	Typical price
Water Pump	928.106.032.04	$150–250
Thermostat	928.106.127.01	$40–80
Radiator	Varies	$300–600

Sources: Pelican Parts, Rennlist

Vacuum System Deterioration

Easy

Symptoms: Climate control not working, doors won't lock, cruise control failure, rough idle, brake booster issues

The 928 uses vacuum for the climate control, central locking, cruise control, and brake booster, and after decades the hoses crack. A car with odd HVAC behavior, locks that don't work, or a rough idle often has one leak causing all of it.

Estimated Repair Costs

DIY $100–300

Shop $300–700

Vacuum runs the HVAC, locks, and cruise. The lines crack with age.

Common Fixes

Replace all vacuum hoses throughout the car
Check and replace vacuum reservoir if cracked
Replace vacuum check valves
Test vacuum actuators in doors and HVAC system
Replace brake booster check valve if brakes feel hard

Common Parts

Part	Part Number	Typical price
Vacuum Hose Kit	Varies	$80–200
Vacuum Reservoir	928.571.121.01	$50–100

Sources: 928 Specialists, Rennlist

Weissach Axle Bushing Wear

Advanced

Symptoms: Rear-end wander, unpredictable handling at limit, clunking from rear, uneven rear tire wear

Every 928 uses the Weissach rear axle, which lets the rear wheels toe in slightly under braking and cornering loads to keep the car stable. It relies on a set of bushings and links, and when they wear the rear end feels loose and the passive steering effect disappears.

Estimated Repair Costs

DIY $300–600

Shop $800–1,500

Several bushings and links. Do them together.

Common Fixes

Inspect all Weissach axle bushings for wear
Replace control arm bushings (polyurethane or oem rubber)
Replace toe links and trailing arm bushings
Check wheel bearings for play
Rebuild or replace control arms if ball joints worn
Perform full rear alignment after suspension work

Common Parts

Part	Part Number	Typical price
Weissach Bushing Kit	Varies	$150–300
Toe Link	928.331.047.00	$80–150

Sources: 928 International, Rennlist

Pop-Up Headlight Failure

Moderate

Symptoms: Headlights stuck up or down, slow headlight operation, one headlight won't open, motor noise but no movement

The pop-up headlights are driven by electric motors through cables and linkages. Motors fail, cables stretch or break, and plastic linkage parts crack. Regular cleaning and lubrication prevent most of it.

Estimated Repair Costs

DIY $50–200

Shop $200–500

Lubrication prevents most failures.

Common Fixes

Lubricate headlight pivot points with white lithium grease
Replace headlight cables if stretched or frayed
Replace headlight motor if failed
Replace plastic linkage components if cracked
Adjust limit switches for proper open/close positions

Common Parts

Part	Part Number	Typical price
Headlight Motor	928.631.101.00	$150–300
Headlight Cable	928.631.203.00	$40–80

Sources: Rennlist, Pelican Parts

Instrument Cluster and Electronics

Easy

Symptoms: Dead or flickering gauges, inaccurate readings, warning lights stuck on, odometer failure, dim display

The cluster's circuit board develops cracked solder joints from heat cycling, capacitors fail, and the displays fade. Specialist rebuild services fix all of it.

Estimated Repair Costs

DIY $100–300

Shop $300–700

Rebuild services are available.

Common Fixes

Re-solder cracked connections on cluster circuit board
Replace failed capacitors
Replace lcd displays with new or nos units
Replace odometer gears (brass upgrade kits available)
Have cluster professionally rebuilt by 928 specialist

Common Parts

Part	Part Number	Typical price
Cluster Rebuild Service	Varies	$200–500
Odometer Gear Kit	Varies	$20–50

Sources: 928 Specialists, Rennlist

Air Conditioning System Failures

Moderate

Symptoms: No cold air, weak airflow, hot on one side and cold on the other, clicking from dashboard, refrigerant leaks

The automatic climate control was advanced in its day and is old now. Compressors, condensers, and evaporators wear out, and many R12 systems were converted to R134a badly. A proper conversion, or a correct R12 service where it's legal, makes a big difference.

Estimated Repair Costs

DIY $200–500

Shop $600–1,500

Many conversions to R134a were done poorly.

Common Fixes

Properly convert R12 systems to R134a
Replace compressor if failed or worn
Replace condenser and receiver/drier if system was open
Repair or replace evaporator if leaking
Replace blend door servo motors
Check vacuum supply to HVAC system

Common Parts

Part	Part Number	Typical price
AC Compressor	Varies	$300–600
R134a Conversion Kit	Varies	$100–200

Sources: Rennlist, 928 International

Restoration Guides

The bigger jobs: step-by-step, with parts lists, tools, and the mistakes to avoid.

Complete Suspension Refresh

Intermediate to Advanced 14-20 hours $800-2,000

Every joint and bushing, including the Weissach rear axle every 928 uses. A fresh 928 chassis rides and handles far better than most people expect.

Interval Every 60,000-80,000 miles or when handling degrades

Cost (DIY) $800-2,000

Labor 12-18 hours shop time

Parts List

Part	OEM part #	Aftermarket	Typical cost
Front Strut (Each)	92834301502	Bilstein B4, Koni	$150-300
Rear Shock Absorber (Each)	92833030301	Bilstein B4, Koni	$150-280
Front Control Arm Bushing Set	92834199101	URO, Elephant Racing	$80-160
Front Strut Mount (Each)	92834302701	URO, aftermarket	$60-120
Front Ball Joint (Each)	92834153201	Lemforder, Meyle	$50-100
Tie Rod End (Each)	92834703301	Lemforder, Meyle	$50-90
Weissach Bushing Kit (S4/GTS)	Various	Elephant Racing, URO	$150-300
Rear Toe Link (Each)	92833104700	Lemforder, URO	$80-150
Rear Trailing Arm Bushing (Each)	92833114102	URO, aftermarket	$50-100
Sway Bar End Link (Front, Each)	92834306902	URO, aftermarket	$35-70

Tools

Floor jack and jack stands rated for vehicle weight
19mm socket for lug bolts
18mm, 19mm, 21mm, 24mm sockets and wrenches
Pickle fork or ball joint separator
Spring compressor (front struts)
Torque wrench (ft-lbs range)
Bushing press or hydraulic press
Penetrating oil (PB Blaster)
Alignment tool set (optional)
Breaker bar for stubborn fasteners
Large pry bar for control arm manipulation

Step by step

Raise vehicle and support securely on jack stands under reinforced jacking points.
Remove all four wheels and set aside.
Document current ride height and alignment settings before disassembly.
Begin with front suspension—disconnect sway bar end links.
Remove tie rod ends from steering knuckle using pickle fork.
Remove front ball joints from control arms.
Support the strut assembly before removing top mount bolts.
From inside the hood, remove the three strut top mount nuts.
Remove strut assembly and use spring compressor to disassemble.
Replace strut cartridge, mount, and bearing as needed.
Reassemble strut and install in vehicle.
Replace front control arm bushings using press.
For rear suspension, identify if car has standard or Weissach axle.
Weissach axle (S4/GT/gts) has multiple control arms and links.
Remove upper control arms—note any shim washers for alignment.
Remove lower control arms and toe links.
Replace all Weissach bushings—they affect handling significantly.
Replace rear shock absorbers—access through wheel well.
For non-Weissach models, replace trailing arm bushings.
Reassemble in reverse order, torquing all fasteners to spec.
Front control arm bolts: 63 ft-lbs (85 Nm).
Weissach control arm bolts: 74 ft-lbs (100 Nm).
Strut top mount: 44 ft-lbs (60 Nm).
Install wheels and torque lug bolts to 96 ft-lbs (130 Nm).
Get a professional alignment afterward. The 928 has a lot of adjustment points.

Tips

The 928's Weissach rear axle provides passive rear steering for stability.
Worn Weissach bushings cause unpredictable handling at the limit.
Elephant Racing offers excellent polyurethane bushing kits.
Bilstein B4 or Koni adjustables are popular shock upgrades.
The 928 is heavy (3,400+ lbs)—ensure proper support during work.
Check wheel bearings while suspension is disassembled.
Consider lowering springs (H&R, Eibach) if updating for performance.

Watch out

The 928 is heavy—use appropriately rated jack stands.
Spring compressors are dangerous—ensure proper safety.
The Weissach axle is complex—take photos and label everything.
Worn Weissach components can cause dangerous handling at speed.
Always tighten suspension fasteners with weight on wheels.
Professional alignment is required after rear suspension work.

References

Rust Prevention and Repair

Intermediate to Advanced 8-40+ hours depending on severity $200-3,000+

Rockers, floors, rear quarters, and the battery area. The body is galvanized, but water still finds its way in.

Interval Annual inspection, repair as needed

Cost (DIY) $200-3,000+

Labor Varies significantly by extent of rust

Parts List

Part	OEM part #	Aftermarket	Typical cost
Rocker Panel (Left)	92850349100	Reproduction available	$400-800
Rocker Panel (Right)	92850349200	Reproduction available	$400-800
Floor Pan Repair Section	Various	Fabricated panels	$200-500
Rear Quarter Repair Panel	Various	Reproduction	$300-700
Battery Tray	92861213100	Fabricated	$100-250
Door Skin (If needed)	Various	Reproduction limited	$400-900
POR-15 Rust Preventive Coating	N/A	POR-15	$40-80
3M Underseal Rubberized Coating	N/A	3M	$15-25
Weld-Through Primer	N/A	Eastwood, 3M	$15-30
Body Seam Sealer	N/A	3M, Eastwood	$20-40

Tools

Wire brush and wire wheel attachments
Angle grinder with cutting and grinding discs
MIG welder (minimum 140A recommended)
Body panel clamps and magnets
Aviation snips for sheet metal
Sandblaster or chemical rust remover
Seam sealer applicator gun
Body filler and spreaders
DA sander with various grit discs
Spray gun for primer and underseal
Safety equipment: welding helmet, gloves, respirator

Step by step

Thoroughly clean undercarriage with pressure washer to expose rust areas.
Raise vehicle and inspect all common rust locations systematically.
The 928 has galvanized body panels but still develops rust over time.
Check rocker panels by pressing firmly—soft spots indicate internal rust.
Inspect battery tray area for acid damage and corrosion.
Examine floor pans from inside with carpet removed and from below.
Check rear quarters near wheel wells for stone damage and rust.
Inspect door bottoms and under side moldings.
Check suspension mounting points for structural rust.
For surface rust: sand to bare metal, treat with rust converter, prime and seal.
For perforation rust: cut out affected area 1 inch beyond visible rust.
The 928's galvanizing makes welding more challenging—clean thoroughly.
Fabricate or purchase repair panels to fit openings.
Apply weld-through primer to mating surfaces.
Tack weld panels in place, checking fit frequently.
Finish weld using stitch welding to prevent warpage.
Grind welds smooth and apply seam sealer to all joints.
Treat interior surfaces with rust preventive (por-15 or equivalent).
Apply rubberized underseal to exterior underbody surfaces.
Prime and paint repaired areas to match existing finish.
Apply cavity wax to all hollow sections for ongoing protection.

Tips

The 928 has galvanized body panels—less rust-prone than other cars of the era.
Rust often starts where galvanizing was damaged by stone chips or scratches.
Battery acid damage is common even with relocated batteries (spills during service).
Door bottoms and rocker panels are most vulnerable to water intrusion.
Reproduction panels are limited—fabrication may be necessary.
Consider professional inspection before purchasing to assess rust severity.
The 928's value is increasing—quality repairs are worthwhile.

Watch out

Extensive rust repair can still exceed the vehicle's value on early cars.
Welding galvanized metal produces toxic fumes—work outdoors or with excellent ventilation.
Welding near fuel lines and tank requires proper safety precautions.
Improper structural repairs can affect crash safety.
Rust preventive coatings require proper ventilation and safety equipment.
Disconnect battery and fuel system before any welding operations.

References

Electrical System Restoration

Intermediate to Advanced 8-24 hours depending on scope $200-1,500

The engine harness, DME, vacuum-operated accessories, pop-up headlights, and the cluster. The 928 has more electrical systems than anything else Porsche built in its day.

Interval Inspect every 2-3 years, service as needed

Cost (DIY) $200-1,500

Labor 6-20 hours shop time

Parts List

Part	OEM part #	Aftermarket	Typical cost
Engine Wiring Harness (Rebuilt)	Various by year	Specialist rebuilt	$500-1,500
Harness Repair Kit	N/A	Various suppliers	$50-150
DME Relay	92861510100	Bosch	$40-80
Fuel Pump Relay	92861510101	Bosch	$35-70
Alternator (Rebuilt)	92860301502	Bosch rebuilt	$250-500
Headlight Motor	92863110100	Rebuilt available	$150-300
Headlight Cable	92863120300	Aftermarket	$40-80
Instrument Cluster Capacitor Kit	N/A	Various	$30-70
Odometer Gear Kit (Brass)	N/A	Various	$20-50
Ground Wire Kit	Various	Custom fabrication	$50-120

Tools

Digital multimeter with amp clamp
12V test light
Wire crimping tool set
Soldering iron and electronics solder
Heat shrink tubing assortment
Dielectric grease
Battery terminal cleaner
Small picks and probes for connectors
Wire strippers
Electrical contact cleaner
Heat-resistant wire loom and tape
Torx and Phillips screwdrivers

Step by step

Disconnect battery before any electrical work—negative terminal first.
Test battery condition—load test and check voltage (should be 12.6V resting).
Clean and tighten all battery connections with terminal cleaner.
Test alternator output—should be 13.8-14.4V at idle.
The 928 engine harness is a common failure point—inspect thoroughly.
Look for cracked, brittle, or heat-damaged insulation in the engine bay.
If harness is damaged, consider professional rebuild or replacement.
For minor damage, wrap affected areas with heat-resistant loom.
Locate the fuse/relay panel—test DME and fuel pump relays.
Check and clean all ground connections throughout the vehicle.
Main engine ground connections should be cleaned to bare metal.
Test and service pop-up headlight motors and cables.
Lubricate headlight pivot points with white lithium grease.
Replace stretched or frayed headlight cables.
For instrument cluster issues, remove and inspect circuit board.
Resolder cold solder joints and replace failed capacitors.
Replace odometer gears with brass upgrade kit if stuck.
Test all vacuum-operated electrical components (locks, HVAC).
Inspect and clean all multi-pin connectors.
Apply dielectric grease to all cleaned connections.
Add heat shielding to protect harness from exhaust heat.
Reconnect battery and test all systems.

Tips

The 928's engine harness deteriorates from heat—this is the #1 electrical issue.
Rebuilt harnesses are available from 928 specialists and are worthwhile.
The instrument cluster has known issues—capacitor and solder joint repair is common.
Pop-up headlights require regular lubrication for reliable operation.
The 928 uses vacuum for door locks, HVAC, and cruise—check vacuum lines too.
Good grounds matter—clean and protect them.
Document any wiring changes with photographs for future reference.

Watch out

Always disconnect battery before working on electrical systems.
The 928 may have airbags (later models)—wait 10 minutes after disconnecting battery.
Engine harness work near hot exhaust requires care—engine must be cold.
Incorrect relay replacement can damage the DME computer.
Static electricity can damage electronic components—ground yourself.
Some 928 electrical components are expensive and hard to find—test before replacing.

References

Interior Restoration

Intermediate 16-40 hours for complete restoration $600-3,500+

Leather, carpet, door panels, dash, and HVAC. A 928 cabin is a nice place to be when it's sorted.

Interval As needed based on condition

Cost (DIY) $600-3,500+

Labor 12-30 hours shop time

Parts List

Part	OEM part #	Aftermarket	Typical cost
Leather Seat Cover Kit (Per Seat)	Various by color	Leatherique, Alea Leather	$400-1,000
Carpet Set	Various by color	Autoloc, aftermarket	$400-900
Door Panel Set	Various	Used or refurbished	$300-700
Seat Foam Cushion	Various	Various	$150-350
Leather Conditioner/Dye Kit	N/A	Leatherique, Connolly	$60-140
Door Seal Kit (Complete)	Various	German OEM suppliers	$300-700
Shift Boot (Auto/Manual)	Various	Aftermarket leather	$60-130
Sun Visor Set	Various	Used or refurbished	$100-250
Dashboard (If cracked)	Used only	Very limited	$500-1,500
HVAC Blend Door Servo	Various	Rebuilt	$100-250

Tools

Trim panel removal tools (plastic pry bars)
Torx driver set (T20, T25, T30)
Hog ring pliers and hog rings
Heat gun for leather work
Leather cleaning brushes
Interior detailing brushes
Spray bottle for cleaning solutions
Seam roller for carpet installation
Steam cleaner (optional but helpful)
Rivet gun for door panels
Upholstery adhesive

Step by step

Remove seats by unbolting from floor (4 bolts per seat, 13mm).
Disconnect electrical connectors for power seats and heated seats.
The 928 has excellent leather seats that respond well to conditioning.
Clean seats thoroughly with quality leather cleaner.
For worn leather: apply Leatherique or similar conditioner system.
For cracked/torn leather: professional reupholstery or cover kit.
Remove hog rings to separate leather from foam if recovering.
Replace foam cushions if compressed—common on driver's side.
Install new covers using hog rings at attachment points.
Remove door panels by removing screws and popping clips.
The 928 door panels are well-made but clips become brittle.
Clean or replace door panel leather/vinyl as needed.
Remove old carpet by removing sill plates, console, and seat bases.
Clean and treat floor pan with rust preventive if any bare metal.
Install new carpet kit, starting from rear and working forward.
The 928 dashboard can crack—prevent with dashboard pad.
If dashboard is cracked, used replacement is only option.
Clean dashboard with appropriate cleaner—avoid silicone products.
Service HVAC system—test blend door servos and vacuum operation.
Replace blend door servos if clicking or not responding.
Replace blower motor if noisy or weak airflow.
Test all interior functions before final assembly.

Tips

The 928 has luxury interior—often cleaning and conditioning is sufficient.
Leatherique can revive very dried and cracked leather.
The 928 dashboard is prone to cracking—used replacements are very expensive.
Prevent dashboard cracks with quality dashboard pad and window tinting.
Door panel clips are fragile—have extras on hand before removal.
The 928's HVAC uses vacuum servos—check vacuum system too.
Power seat tracks should be lubricated while seats are out.
The 928's carpets are complex—take photos before removal.

Watch out

Later 928s have airbags—disconnect battery and wait 10 minutes before working near steering wheel.
Power seat motors carry significant current—disconnect battery first.
Leather dyes can stain surrounding surfaces—mask carefully.
Silicone-based products leave residue that interferes with future repairs.
Dashboard replacement is a major undertaking—consider professional help.
Heat gun can damage leather if held too close—keep moving.

References

Timing Belt and Water Pump (928 V8)

Advanced 10-16 hours $500-1,000

The 928's belt drives both camshaft banks and the water pump on an interference V8. It's a long job with a long list of parts, and skipping it is how 928s end up as parts cars.

Cost (DIY) $500-1,000

Parts List

Part	OEM part #	Aftermarket	Typical cost
Timing belt	—	Contitech	$60-120
Tensioner rebuild parts and rollers	—	—	$150-300
Water pump and gasket	—	—	$150-300
Cam and crank seals	—	—	$40-80
Coolant	—	—	$40-60

Tools

928 belt tension gauge (or a specialist-recommended alternative)
Crank holding tool
Metric sockets and wrenches
Torque wrench
Drain pan

Step by step

Disconnect the battery and drain the coolant.
Remove the fan shroud, accessory belts, and the timing covers.
Set the engine to TDC and confirm the marks on both cam sprockets and the crank.
Inspect the tensioner, rollers, and water pump for play or leaks before removing the belt.
Relieve the tensioner and remove the belt.
Replace the water pump, rollers, and tensioner parts, and the front seals if they're weeping.
Fit the new belt with all marks aligned.
Set the tension with the gauge per the workshop manual.
Rotate the engine two full turns by hand, recheck the marks, and recheck tension.
Reassemble, refill, and bleed the cooling system. Recheck tension after the first few hundred miles if the manual calls for it.

Tips

The tensioner's condition matters as much as the belt. A worn tensioner will ruin a new belt.
The 928 specialists sell complete kits. They're worth it.

Watch out

Incorrect tension is a common cause of 928 belt failures.
Never turn the engine backward with the belt fitted.

References

DIY Maintenance

The routine work you can do on a Saturday with hand tools and jack stands.

Oil Change

Easy 45 min $60-90

Oil and filter on the V8. Allow a bit longer than you'd think.

Interval Every 5,000-7,500 miles

Cost (DIY) $60-90

Tools

19mm socket for drain plug
Oil filter wrench
Drain pan (2 gallon capacity)
Funnel
Jack and jack stands or ramps

Step by step

Warm the engine for 2-3 minutes to thin the oil.
Raise the front of the car safely or drive onto ramps.
Locate the oil drain plug on the oil pan—passenger side.
Position the drain pan and remove the 19mm drain plug.
Allow oil to drain completely—at least 15 minutes for the V8.
The spin-on oil filter is on the passenger side of the engine, accessible from below.
Using the oil filter wrench, remove the old filter.
Apply a thin film of fresh oil to the new filter's gasket.
Thread the new filter on by hand until seated, then 3/4 turn more.
Replace the crush washer on the drain plug.
Reinstall drain plug and torque to 22 ft-lbs (30 Nm).
Lower the car and add 8-9 quarts of 15W-50 or 20W-50 oil.
Start engine and check for leaks at drain plug and filter.
Shut off, wait 3 minutes for oil to settle, check level and top off.

Tips

The 928 V8 holds 8-9 quarts depending on model year and oil cooler.
Use quality synthetic 15W-50 for hot climates or track use.
Check for oil leaks at cam tower gaskets while under the hood.

Pop-Up Headlight Lubrication

Easy 30 min $10-20

Pop-up headlights stick when their mechanisms dry out. Clean and lube them before the motors or gears fail.

Interval Every 6 months or annually

Cost (DIY) $10-20

Tools

White lithium grease spray
Clean rags
Flashlight
Small brush

Step by step

Turn on the headlights to raise them to the up position.
Turn off the engine and headlights, leaving them raised.
Open the hood for access to the headlight mechanisms.
Locate the headlight pivot points on each side.
Clean old grease and debris from the pivot points and linkages.
Apply white lithium grease to all pivot points.
Lubricate the cable pulleys and guide tracks.
Apply grease to the motor output shaft area (accessible with brush).
Operate the headlights up and down several times to distribute grease.
Wipe away any excess grease that could attract dirt.
Check that both headlights operate at the same speed.
If one is slower, inspect cable tension and motor condition.

Tips

Slow or uneven headlight operation usually means it's time for lubrication.
Don't use WD-40—it's not a lubricant and attracts dust.
If headlights still operate slowly after lubrication, check motor brushes.
Stretched or frayed cables should be replaced, not just lubricated.

Brake Pad Replacement

Easy 1-2 hours $100-180

Front and rear pads with a rotor check.

Interval Every 25,000-40,000 miles

Cost (DIY) $100-180

Tools

19mm socket for lug bolts
7mm Allen socket for caliper pins
C-clamp or brake piston tool
Wire brush
Brake cleaner
Brake grease
Jack and jack stands

Step by step

Loosen lug bolts while the car is on the ground.
Raise and support the car safely on jack stands.
Remove wheel to access the caliper.
Remove the two caliper guide pin bolts (7mm Allen on most).
Swing the caliper up and support it—never let it hang by the hose.
Remove the old pads from the caliper bracket.
Inspect rotor for scoring, cracks, or thickness below minimum.
Clean the pad contact surfaces with wire brush.
Open brake fluid reservoir, then compress caliper piston.
Apply brake grease to pad backing plate edges.
Install new pads in the bracket.
Swing caliper back over pads and reinstall guide pin bolts.
Torque caliper bolts to 63 ft-lbs (85 Nm).
Reinstall wheel and torque lug bolts to 96 ft-lbs (130 Nm).
Repeat for all corners.
Pump brake pedal until firm before driving.

Tips

The 928 uses large brakes with good pad life.
Bed in new pads with moderate stops—avoid panic stops for 100 miles.
Consider upgrading to ceramic or performance pads for less dust.

Vacuum System Inspection

Easy 1 hour $30-80 for replacement hoses

Cracked vacuum lines cause a surprising list of 928 faults, from HVAC to idle. How to find the leaks.

Interval Annually or when systems malfunction

Cost (DIY) $30-80 for replacement hoses

Tools

Flashlight
Inspection mirror
Vacuum line kit (various sizes)
Vacuum gauge (optional)
Carburetor cleaner for leak detection

Step by step

Start with the engine cool and off.
Open the hood and locate the main vacuum reservoir and distribution block.
Visually inspect all visible vacuum lines for cracks, hardening, or collapse.
Check the lines running to HVAC controls (often behind the dashboard).
Inspect vacuum lines to the cruise control system.
Check vacuum lines to the door lock actuators.
Look for lines connected to the brake booster.
With engine running, listen for hissing (vacuum leaks).
Spray carburetor cleaner near suspect areas—idle change indicates leak.
Replace any cracked or hardened lines with proper size vacuum tubing.
Mark replaced lines with tape or tie for future reference.
Test affected systems after repairs (HVAC, locks, cruise, brakes).

Tips

The 928 uses vacuum for HVAC, door locks, cruise control, and brake booster.
Original vacuum lines become brittle after 25+ years.
A failed vacuum system can cause multiple seemingly unrelated failures.
Consider replacing all vacuum lines as preventive maintenance.

Torque Specs

Values for common service jobs. Check the source listed for each table, and your own manual, before you torque anything critical.

Where these numbers come from

Engine

Component	Torque Spec	Notes
Cylinder Head Bolts (S4/GTS)	Torque-to-yield sequence	See manual for multi-stage procedure
Timing Belt Tensioner	33 ft-lbs (45 Nm)	-
Timing Belt Rollers	33 ft-lbs (45 Nm)	-
Spark Plugs	22 ft-lbs (30 Nm)	-
Cam Tower Bolts	7 ft-lbs (10 Nm)	Tighten evenly in pattern
Oil Drain Plug	22 ft-lbs (30 Nm)	Replace washer
Water Pump Bolts	15 ft-lbs (20 Nm)	-
Intake Manifold Bolts	7 ft-lbs (10 Nm)	-

Suspension

Component	Torque Spec	Notes
Wheel Lug Bolts (M14)	96 ft-lbs (130 Nm)	Tighten in star pattern
Front Control Arm Bolts	63 ft-lbs (85 Nm)	-
Weissach Axle Control Arms	74 ft-lbs (100 Nm)	S4/GTS only
Tie Rod Ends	33 ft-lbs (45 Nm)	Use new cotter pin
Strut Top Mount	44 ft-lbs (60 Nm)	-

Brakes

Component	Torque Spec	Notes
Caliper Bolts	63 ft-lbs (85 Nm)	-
Brake Line Fittings	11 ft-lbs (15 Nm)	Do not overtighten

Parts & Suppliers

Where I'd shop for 928 parts: genuine, performance, used, and the specialists.

OEM Featured

Porsche Classic

Factory parts program for classic Porsches - 928 parts availability continues to improve

Factory Original Genuine Porsche

Genuine OEM

OEM Featured

Pelican Parts

Deep 928 parts catalog with detailed diagrams and tech articles

OEM Parts Tech Articles 928 Coverage

Free over $99

OEM

Sunset Porsche Parts

Porsche dealer parts with competitive pricing on genuine parts

OEM Dealer New Genuine Parts

Fast shipping

Performance Featured

928 Motorsports

Performance upgrades specifically designed for the 928 platform

Engine Upgrades Suspension Performance

Performance

Devek

928 performance specialist known for engine and transmission work

Engine Builds Transmissions

Performance

Elephant Racing

Premium suspension upgrades - 928 kits available

Suspension Handling Kits

General

AutohausAZ

Large selection of replacement parts at competitive prices

Replacement Parts Maintenance Items

Free over $99

General

FCP Euro

Lifetime replacement guarantee on everything they sell

Lifetime Warranty OE Quality

Free over $49 Lifetime

Specialist Featured

928 International

Long-time 928 specialist with a deep inventory, including the hard-to-find parts

928 Exclusive Rare Parts Expertise

Specialist Featured

928 Specialists

Decades of 928 experience—parts, service, and restoration

928 Exclusive Full Service Restoration

Specialist

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928-only specialists with parts and technical support

928 Exclusive Technical Support

Specialist

928s R Us

UK-based 928 specialist with international shipping

European Parts 928 Exclusive

International

Used/NOS Featured

928 Forum Classifieds

Dedicated 928 community marketplace—the first place to look for used parts

928 Exclusive Community Vetted

Used/NOS

Rennlist 928 Classifieds

Large Porsche community with active 928 section

Forum Marketplace Wide Selection

Used/NOS

eBay Motors

Global marketplace for used and NOS 928 parts

Used Parts NOS Global Sellers

Used/NOS

Car-Part.com

Search nationwide salvage yard inventory - 928s are getting rare

Salvage Parts Low Cost

Useful references

928 Spec Database Detailed 928 specifications, production numbers, and technical data Porsche Parts Diagrams Pelican's parts diagrams help identify correct part numbers by year 928 International Tech Library Extensive DIY guides and technical articles specific to the 928

Community Resources

Where 928 owners hang out: forums, YouTube channels, and clubs worth your time.

Own a 928?

Track it in My Garage

Add your car and you get a 928 service schedule with intervals already filled in, a restoration tracker organized by system, and a log of every job and what it cost. It's free, and it's the same on your phone and your laptop.

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Porsche 928

Common Issues

Timing Belt Failure

Estimated Repair Costs

Common Fixes

Common Parts

Same problem on other cars

Cam Tower Gasket and Oil Leaks

Estimated Repair Costs

Common Fixes

Common Parts

Engine Wiring Harness Deterioration

Estimated Repair Costs

Common Fixes

Common Parts

Automatic Transmission Issues

Estimated Repair Costs

Common Fixes

Common Parts

Cooling System Failures

Estimated Repair Costs

Common Fixes

Common Parts

Vacuum System Deterioration

Estimated Repair Costs

Common Fixes

Common Parts

Weissach Axle Bushing Wear

Estimated Repair Costs

Common Fixes

Common Parts

Pop-Up Headlight Failure

Estimated Repair Costs

Common Fixes

Common Parts

Instrument Cluster and Electronics

Estimated Repair Costs

Common Fixes

Common Parts

Air Conditioning System Failures

Estimated Repair Costs

Common Fixes

Common Parts

Restoration Guides

Complete Suspension Refresh

Parts List

Tools

Step by step

Tips

Watch out

References

Rust Prevention and Repair

Parts List

Tools

Step by step

Tips

Watch out

References

Electrical System Restoration

Parts List

Tools

Step by step

Tips

Watch out

References

Interior Restoration

Parts List

Tools

Step by step

Tips

Watch out

References

Timing Belt and Water Pump (928 V8)

Parts List

Tools

Step by step

Tips

Watch out

References

DIY Maintenance