IsItAGoodCar
Reliability Guide

Common Problems with the
1998 Porsche 911 (996)

The 1998 launch of the 996 marked the most radical change in the 911's history, moving from air-cooled to water-cooled engines to meet emissions standards. While dynamically brilliant, its 'fried egg' headlights and shared Boxster front-end were highly controversial.

What changed for 1998

  • •Introduction of the first water-cooled 911, featuring an all-new chassis.
  • •Debuted with the 3.4-litre M96 flat-six engine.

Common MOT watch-outs

  • !Emissions failures related to aging catalytic converters.
  • !Suspension component wear, particularly the lower 'coffin' arms.
3
Known Issues
1
Serious
2
Moderate
0
Minor

All Known Issues

IMS Bearing Failure

SeriousEngine

Early M96 engines can suffer intermediate shaft bearing failure, leading to major internal damage.

Est. Repair Cost: £1,500–£2,500 (preventative)
Warning Signs:

Metal debris in oil filter, Oil leak near rear main seal area, Sudden catastrophic engine failure

What to Inspect:
  • Ask if an IMS upgrade has been fitted
  • Inspect the oil filter at service
Verified by IsItAGoodCar Research Team

Rear Main Seal Oil Leak

ModerateEngine

The rear main seal between engine and gearbox degrades over time, causing oil to leak into the bellhousing area. Often mistaken for IMS failure.

Est. Repair Cost: £1,500–£2,500
Warning Signs:

Oil drip under car when parked, Oil residue between engine and gearbox, Burning oil smell

What to Inspect:
  • Inspect bellhousing area for oil residue
  • Check oil level between services
Verified by IsItAGoodCar Research Team

Coolant Pipe Failures

ModerateCooling System

The coolant crossover pipes and thermostat housing o-rings perish, causing coolant loss and potential overheating. Plastic degrades with heat cycles.

Est. Repair Cost: £400–£800
Warning Signs:

Sweet coolant smell, Low coolant warning, Coolant dripping under car

What to Inspect:
  • Check coolant level
  • Inspect crossover pipes for staining or corrosion
Verified by IsItAGoodCar Research Team

Buying Tips for 1998 Porsche 911 (996)

  • ✓The IMS (Intermediate Shaft) bearing is a notorious failure point; demand proof of an upgraded bearing or budget £1,500+ to do it immediately.
  • ✓Check the coolant header tank for cracks and leaks, a common issue as the plastic ages.
19971999–2001
Check a 1998 Porsche 911 (996) by Registration