IsItAGoodCar
Reliability Guide

Common Problems with the
2003 MG ZT / ZT-T

2003 was the ZT's busiest year: the 1.8 120 and turbocharged 1.8T 160 arrived in July, and the rear-wheel-drive 260 V8 with a 4.6-litre Ford Modular engine followed in October.

What changed for 2003

  • •1.8 120 entry model and 1.8T 160 replacing the detuned V6
  • •ZT 260 with a 4.6-litre V8, rear-wheel drive and 260PS
  • •XPower diesel upgrade lifting the CDTi from 116PS to 131PS

Common MOT watch-outs

  • !Emissions failures on the 1.8T from a tired catalyst
  • !Corroded fuel and brake pipes on V8 cars stored off the road
  • !Worn rear subframe bushes on V8 models
5
Known Issues
3
Serious
1
Moderate
1
Minor

All Known Issues

ECU Flooding (Blocked Drains)

SeriousElectrics & Electronics

The plenum chamber drains block with leaves, causing water to rise and submerge the engine ECU.

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

Car cuts out, Refusal to start, Random electrical glitches

What to Inspect:
  • Reach into the plenum (below wipers) and feel for standing water or debris
  • Ensure the drain "rubbers" have been cleared or removed
Verified by IsItAGoodCar Research Team

K-Series Head Gasket Failure (1.8 Petrol)

SeriousEngine

The 1.8 K-Series petrol engine is prone to head gasket failure if the cooling system is neglected. Symptoms include overheating and oil/coolant mixing.

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

Overheating, Oil in coolant / Coolant in oil, Loss of heater performance

What to Inspect:
  • Check the oil filler cap and expansion tank for contamination
  • Verify the coolant level and condition
Verified by IsItAGoodCar Research Team

Brake Pipe Corrosion

SeriousBrakes

The brake pipes can corrode, particularly in areas where road salt is used. This is a serious safety concern and a common MOT failure point.

Est. Repair Cost: £100–£300
Warning Signs:

Spongy brake pedal, Brake fluid leak, MOT failure on corroded pipes

What to Inspect:
  • Inspect the brake pipes for rust and leaks
  • Check the MOT history for brake-related failures
Verified by IsItAGoodCar Research Team

Front Coil Spring Breakage

ModerateSuspension & Chassis

The front coil springs are prone to snapping due to fierce corrosion, particularly on UK roads with salt and potholes. This is a common MOT failure.

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

Clunking from the front end, Car sitting lower on one side, MOT failure on broken spring

What to Inspect:
  • Inspect the front springs for corrosion and cracks
  • Check the MOT history for spring-related failures
Verified by IsItAGoodCar Research Team

Electric Seat Motor Failure

MinorInterior & Trim

The electric seat adjustment motor is not hugely reliable and can fail, leaving the seat stuck in one position.

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

Seat adjustment motor not responding, Seat stuck in one position, Grinding noise from seat motor

What to Inspect:
  • Test the electric seat adjustment through its full range
Verified by IsItAGoodCar Research Team

Buying Tips for 2003 MG ZT / ZT-T

  • On the 260, listen for differential or drive shaft whine on the test drive
  • Verify the 1.8T has had its cambelt and head gasket attended to
  • Check that the XPower upgrade is documented on a 131PS CDTi
20022004
Check a 2003 MG ZT / ZT-T by Registration