IsItAGoodCar
Reliability Guide

Common Problems with the
2004 MG Rover Rover 25 / MG ZR

The 2004 facelift by Peter Stevens introduced smooth aerodynamic bumpers, clear one-piece headlamps, a push-button boot release, circular interior vents and updated Pektron security electronics.

What changed for 2004

  • •Restyled front bumper with single-piece headlamp units, updated grille, and smoothed rear tailgate with remote release
  • •Completely redesigned dashboard featuring circular chrome-ringed air vents and refreshed console switchgear
  • •Adoption of the Pektron Security Control Unit (SCU) with round key fobs replacing the older Lucas 5AS system
  • •Revised Trophy and Trophy SE equipment grades with distinctive half-leather seats and updated alloy wheel designs

Common MOT watch-outs

  • !Pektron SCU internal relay failure leading to non-functional windscreen wipers, washers, horn, or front indicators
  • !Corrosion of rear arch seams, rear floor pans, and jacking points after years of winter road salt
  • !Inoperative rear number plate lamps and central locking failure from fractured boot hinge wiring harnesses
4
Known Issues
1
Serious
3
Moderate
0
Minor

All Known Issues

K-Series Head Gasket Failure

SeriousEngine

The standard gasket can fail due to plastic dowels and overheating.

Est. Repair Cost: £500–£800
Warning Signs:

Oil/Coolant mixing, Overheating

What to Inspect:
  • Expansion tank and oil cap
Verified by IsItAGoodCar Research Team

SCU / BCU Relay Failure (Pektron)

ModerateElectrics & Electronics

Models from 2003 onwards use a Pektron Security Control Unit. The internal relays fail, affecting windows, wipers, central locking, and alarm.

Est. Repair Cost: £150–£300
Warning Signs:

Intermittent wipers, Central locking not working, Horn failure, Fobs not responding

What to Inspect:
  • Test every electrical switch and the key fobs multiple times
Verified by IsItAGoodCar Research Team

Rusting Rear Arches

ModerateBodywork & Rust

Water gets trapped behind the lip of the rear wheel arches, causing rust to rot through from the inside. This is a common MOT advisory.

Est. Repair Cost: £300–£600
Warning Signs:

Bubbling paint on the rear arch edges, Visible corrosion, MOT advisory on arches

What to Inspect:
  • Feel the inner lip of the rear arches for crusty rust
Verified by IsItAGoodCar Research Team

Sunroof and Tailgate Leaks

ModerateBodywork & Rust

The sunroof drains and tailgate seals are known to leak, causing damp carpets and a musty smell in the cabin. Water can also affect electrical components.

Est. Repair Cost: £50–£200
Warning Signs:

Wet carpets, Damp smell in the cabin, Water pooling in the boot

What to Inspect:
  • Check the carpets for dampness
  • Inspect the sunroof drains and tailgate seals
Verified by IsItAGoodCar Research Team

Buying Tips for 2004 MG Rover Rover 25 / MG ZR

  • Test every electrical function operated by the Pektron SCU, including all windows, wipers, horn and door lock fobs
  • Verify the electronic boot release switch operates reliably from both the dashboard button and key fob
  • Check coolant level and look for signs of coolant leaks from the plastic intake manifold gasket and thermostat housing
20032005
Check a 2004 MG Rover Rover 25 / MG ZR by Registration