Common Issues
What goes wrong on the 924, how to spot it, and what it costs to fix.
Symptoms: Engine won't start, loud slapping noise, bent valves after failure, visible belt cracking or fraying
Every 924 drives its camshaft with a rubber belt, and the engines are interference designs, so a snapped belt means bent valves. Replace it every 30,000 to 40,000 miles or four years. The 924S uses the 944's 2.5L, which adds balance shaft belts that must be done at the same time. The 2.0L cars, including the Turbo, don't have balance shafts.
Estimated Repair Costs
DIY
$150–300
Shop
$500–900
Interference engine. Every 30,000–40,000 miles.
Common Fixes
- Replace timing belt every 30,000-40,000 miles or 4 years
- Replace water pump at the same time (driven by timing belt)
- Replace timing belt tensioner and idler rollers
- On 924S/Turbo: replace balance shaft belt simultaneously
- Inspect and replace front crankshaft and camshaft seals if leaking
- Use oem or high-quality belts (Gates, Continental)
Common Parts
| Part |
Part Number |
Typical price |
| Timing Belt |
951.105.151.90 |
$40–70 |
| Tensioner |
951.105.511.00 |
$50–100 |
| Water Pump |
951.106.011.00 |
$60–100 |
Symptoms: Hard starting (especially when cold or hot), rough idle, hesitation under acceleration, poor fuel economy, flooding, black smoke
The 2.0L cars use Bosch K-Jetronic (CIS) mechanical fuel injection. It's clever, durable, and completely dependent on correct fuel pressures, which drift as the warm-up regulator, fuel accumulator, and injectors age. Hard hot starts and rough warm-up are the classic symptoms. Test the pressures before replacing parts. The 924S uses the 944's electronic DME system instead.
Estimated Repair Costs
DIY
$100–400
Shop
$300–800
Test fuel pressures first. The warm-up regulator and accumulator are the usual culprits.
Common Fixes
- Test and set system pressures (control pressure, system pressure, residual pressure)
- Replace warm-up regulator (wur) if control pressure is incorrect
- Clean or replace fuel injectors (rebuild kits available)
- Replace fuel accumulator if car is hard to hot-start
- Check fuel pump delivery volume and pressure
- Inspect air flow sensor plate for smooth movement
- Replace all rubber fuel lines (ethanol degrades old rubber)
Common Parts
| Part |
Part Number |
Typical price |
| Warm-Up Regulator |
Bosch |
$200–400 |
| Fuel Accumulator |
Bosch |
$100–200 |
| Fuel Injector (each) |
Bosch |
$40–80 |
Symptoms: Heavy clutch pedal, clutch slipping, difficulty shifting, clutch pedal sticks down, grinding when shifting
The clutch is cable-operated, and the cable runs a long way through the central tunnel to the transaxle at the back. It stretches with age, and the guide tube wears, so the pedal gets heavy and the engagement point moves. Adjust it first; replace it if adjustment doesn't bring it back.
Estimated Repair Costs
DIY
$50–100
Shop
$150–300
Adjust first, then replace.
Common Fixes
- Adjust clutch cable to restore proper free play
- Replace clutch cable if stretched beyond adjustment or frayed
- Lubricate cable guide tube if pedal feel is poor
- When replacing clutch, always replace throwout bearing, pilot bearing, and clutch fork
- Consider upgraded clutch kits for spirited driving
Common Parts
| Part |
Part Number |
Typical price |
| Clutch Cable |
944.237.211.06 |
$40–80 |
Symptoms: Bubbling paint, visible rust holes, soft floors, leaking trunk or cabin, rusty battery box
Check the battery box first, because acid eats it. Then the front fenders behind the headlights and along the bottom edges, the door bottoms, the rockers, and the area around the rear hatch seal. Later cars are galvanized and hold up better, but 40 years finds every weak spot.
Estimated Repair Costs
DIY
$200–1,000
Shop
$1,000–5,000+
Battery box, fenders, and floors are the common spots.
Common Fixes
- Inspect battery box regularly and neutralize acid
- Check and clear all drain holes (doors, rocker panels, floor plugs)
- Replace front fenders if rust is extensive (reproduction available)
- Weld in repair panels for floor pan rust
- Apply rust prevention coating (por-15, Eastwood)
- Treat cavity areas with rust prevention spray
Common Parts
| Part |
Part Number |
Typical price |
| Fender (Repro) |
Varies |
$150–300 |
| Battery Box Repair |
Varies |
$80–150 |
Symptoms: Intermittent no-start, dead gauges, flickering lights, non-functional windows/mirrors, fuel pump runs constantly
Forty-plus years of heat and vibration take a toll. Corroded grounds, tired wiring insulation, and a failing fuel pump relay cause most problems, and the combination relay on the fuse panel runs several functions and fails often. On a 924S, add the DME relay to the list.
Estimated Repair Costs
DIY
$50–200
Shop
$150–400
Relays and grounds. Carry a spare fuel pump relay.
Common Fixes
- Replace DME/fuel pump relay with new oem unit
- Clean and tighten all ground connections
- Inspect and repair wiring under the hood (heat damage common)
- Replace combination relay if multiple electrical functions affected
- Repair or replace instrument cluster circuit board
- Replace ignition switch if experiencing intermittent starting issues
Common Parts
| Part |
Part Number |
Typical price |
| DME/Fuel Pump Relay |
928.615.301.20 |
$30–60 |
| Combination Relay |
Varies |
$40–80 |
Symptoms: Overheating, coolant leaks, heater not working, temperature gauge fluctuation, steam from engine bay
The water pump is driven by the timing belt, so replace it with every belt job. Radiator plastic end tanks go brittle with age. The Turbo runs hotter and is less forgiving of a tired cooling system.
Estimated Repair Costs
DIY
$150–300
Shop
$400–700
Refresh the whole system on a car this age.
Common Fixes
- Replace water pump with every timing belt service
- Replace thermostat (use oem temperature rating)
- Upgrade to aluminum or modern radiator if plastic tanks cracking
- Replace all coolant hoses (including heater hoses)
- Flush cooling system and use proper coolant
- On turbo models: inspect turbo coolant lines and oil cooler
Common Parts
| Part |
Part Number |
Typical price |
| Water Pump |
951.106.011.00 |
$60–100 |
| Thermostat |
Varies |
$20–40 |
| Radiator |
Varies |
$150–300 |
Symptoms: Grinding when shifting, popping out of gear, whining noise from rear, difficulty engaging reverse, oil leaks
The gearbox and differential sit together at the back in a transaxle. Second-gear synchros wear, the shift linkage gets sloppy over its long run, and a tired transaxle mount makes shifting vague. Use the correct GL-4 gear oil, not GL-5, to protect the synchros.
Estimated Repair Costs
DIY
$100–300
Shop
$400–1,500
Use GL-4 gear oil.
Common Fixes
- Change transaxle fluid regularly with correct GL-4 gear oil
- Replace transaxle mount (donut) if shift quality is poor
- Rebuild or replace shift linkage bushings
- For synchro wear: rebuild transaxle or find quality replacement
- Replace output shaft seals if leaking
Common Parts
| Part |
Part Number |
Typical price |
| Trans Mount (Donut) |
944.333.235.00 |
$30–60 |
| Shift Bushing Kit |
Varies |
$40–80 |
| GL-4 Gear Oil |
Varies |
$30–50 |
Symptoms: Clunking over bumps, vague steering, uneven tire wear, wandering at highway speed, squeaking from front end
Nearly every 924 needs suspension work by now: strut mounts, control arm bushings, tie rod ends, and ball joints. The steering rack can also develop play or leak.
Estimated Repair Costs
DIY
$200–400
Shop
$500–900
Bushings and strut mounts are due on every car this age.
Common Fixes
- Replace strut mounts (bearing and rubber mount)
- Install new shocks/struts (Bilstein, Koni, KW available)
- Replace all control arm bushings
- Replace tie rod ends and check steering rack for play
- Rebuild or replace steering rack if leaking or worn
- Perform full alignment after suspension work
Common Parts
| Part |
Part Number |
Typical price |
| Strut Mount |
Varies |
$40–80 |
| Control Arm Bushing Set |
Varies |
$60–120 |