IsItAGoodCar
Reliability Guide

Common Problems with the
2017–2018 Porsche 911 (991)

We've identified 3 known issues that can affect the 2017–2018 Porsche 911 (991). None are considered critical, but they're worth knowing about before you buy.

3
Known Issues
0
Serious
3
Moderate
0
Minor

All Known Issues

Dynamic Engine Mount (PADM) Failure

ModerateSuspension & Chassis

The electromagnetically controlled engine mounts fail internally, triggering a dashboard warning.

Est. Repair Cost: £1,000–£1,400 per side
Warning Signs:

PADM Fault message, Increased vibration at idle

What to Inspect:
  • Check for active fault codes
  • Listen for engine movement during gear changes
Verified by IsItAGoodCar Research Team

Water Pump Failure

ModerateCooling System

The water pump bearing or impeller can fail, causing coolant loss and overheating. The 991.2 has an extended warranty from Porsche for this issue.

Est. Repair Cost: £600–£1,000
Warning Signs:

Coolant leak, Overheating warning, Grinding noise from engine bay

What to Inspect:
  • Check for coolant residue around pump area
  • Inspect water pump pulley for play
Verified by IsItAGoodCar Research Team

Cracked Ignition Coil Packs

ModerateEngine

Coil packs can crack and fail, causing misfires. Common across all 991 variants and relatively inexpensive to fix.

Est. Repair Cost: £200–£400
Warning Signs:

Engine misfire, Check engine light, Rough idle

What to Inspect:
  • Scan for misfire codes
  • Visually inspect coil packs
Verified by IsItAGoodCar Research Team

Buying Tips for 2017–2018 Porsche 911 (991)

  • Check for "PADM Fault" messages; the active engine mounts are a frequent failure point.
  • Inspect the door panels for warping; the trim can lift away from the window line.
  • Ensure the radiator fans are silent; they can become noisy if debris is trapped.
20162019
Check a 2017–2018 Porsche 911 (991) by Registration