Vauxhall Astra Astra H 1.7 CDTi 100bhp — Dual Mass Flywheel Failure
DMF wear on the Astra H 1.7 CDTi is a high-mileage inevitability. The flywheel's internal dampers lose effectiveness, causing vibration and judder that makes the car unpleasant to drive.
Severity
ModerateDIY Difficulty
Professional Only
Est. Cost
£650–£1000
OBD Codes
None
Flywheel
Typical layout and location for the Flywheel assembly.
Symptoms
- Juddering on pull-away from standstill
- Rattling at idle that disappears when clutch pedal is pressed
- Vibration through gear lever
- Clunking when changing gear
Root Cause
Internal spring dampers in the flywheel lose their effectiveness with mileage and the heavy vibration of a diesel engine. Towing and hill driving accelerate wear.
How To Fix
- Always replace DMF and clutch together — never a new clutch on a worn DMF
- LuK or Sachs kits recommended
- Solid flywheel conversion is a cost-effective long-term solution
- Labour: 4-5 hours. Total: £650-1,000
Estimated Repair Costs
| Repair Option | Est. Cost (GBP) |
|---|---|
| DIY (parts only) | £260–£400 |
| Independent Garage | £650–£1000 |
| Main Dealership | £1040–£1600 |
Other Faults on This Variant
EGR Valve Failure
ModerateThe Isuzu-sourced Z17DTH and Z17DTJ engines in the Astra H have a well-documented EGR valve failure. Carbon deposits cause the valve to stick, resulting in power loss and increased emissions.
DPF Blockage
ModerateDPF-equipped Astra H 1.7 CDTi models (post-2007) suffer from the same DPF blockage issues as most diesel Vauxhalls of this era. Urban use is the root cause.
Injector Failure and Hard Starting
SevereInjector failure on the Z17DTH engine causes misfires, rough running and in advanced cases prevents starting. The solenoid-type injectors used in this engine respond well to professional cleaning.
Disclaimer: Repair cost estimates are indicative and based on community data. Always get a quote from a qualified mechanic before proceeding with any repair.