IsItAGoodCar
Reliability Guide

Common Problems with the
1998 Smart Fortwo (450)

The original Fortwo arrived in the UK in 1998 with a tiny 600cc turbocharged three-cylinder engine. These earliest cars are now the most fragile — the 600cc engine has a limited lifespan due to piston ring wear, and water ingress into the SAM unit can cause catastrophic electrical failure. Only buy if a documented engine rebuild has been performed above 60,000 miles.

What changed for 1998

  • •UK launch
  • •600cc turbocharged three-cylinder engine
  • •Automated manual gearbox
  • •SAM (Signal Acquisition and Management) unit introduced
  • •Revolutionary compact design

Common MOT watch-outs

  • !Engine oil consumption and piston ring wear — 600cc engines rarely last beyond 80k miles
  • !SAM unit water damage from windscreen seal leaks
  • !Three bars of death — gearbox fault display
  • !Cracked ABS reluctor rings from UK salt roads
3
Known Issues
2
Serious
1
Moderate
0
Minor

All Known Issues

Engine Longevity and Oil Consumption

SeriousEngine

The 600cc (pre-2003) and 700cc (post-2003) engines have a limited lifespan. Piston rings wear prematurely, leading to oil burning, fouled plugs, and burnt valves.

Est. Repair Cost: £800–£1,800
Warning Signs:

Blue smoke on acceleration, Misfiring under load, High oil consumption (more than 1L per 1000 miles)

What to Inspect:
  • Check for smoke after the car has idled for 5 minutes
  • Look for oily residue in the TIK pipe (turbo inlet)
  • Ask for compression test results if possible
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Three Bars of Death (Gearbox Fault)

SeriousGearbox & Transmission

A generic error on the dash indicating the gearbox cannot find a gear. Usually caused by a failed actuator, chafed wiring harness, or a worn clutch.

Est. Repair Cost: £200–£700
Warning Signs:

Three horizontal bars on the gear display, Car stuck in neutral, Harsh "clunking" when trying to select gear

What to Inspect:
  • Inspect the wiring harness leading to the gearbox for chafing
  • Check the clutch actuator for free movement
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Cracked ABS Reluctor Rings

ModerateBrakes

The metal rings on the rear driveshafts rust, expand, and snap. This confuses the ABS system.

Est. Repair Cost: £100–£250
Warning Signs:

ABS kicking in at very low speeds on dry roads, ABS light illuminated

What to Inspect:
  • Visually inspect the rings through the rear wheels for cracks or missing teeth
Verified by IsItAGoodCar Research Team

Buying Tips for 1998 Smart Fortwo (450)

  • ✓Prioritise cars with documented engine rebuilds if over 60,000 miles
  • ✓Pull back the carpets to check for moisture near the SAM unit
  • ✓Check that all six spark plugs have been changed, not just the top three
1999–2002
Check a 1998 Smart Fortwo (450) by Registration