IsItAGoodCar
Reliability Guide

Common Problems with the
2003 Lexus RX (XU30)

UK launch of the second-generation RX in May 2003, featuring the 3.0-litre 1MZ-FE V6 petrol engine, a 5-speed automatic gearbox, and standard all-wheel drive. Available in SE and SE-L trims, the latter adding air suspension.

What changed for 2003

  • •UK launch of the XU30 body style with aerodynamic 0.35 Cd drag coefficient
  • •3.0-litre 1MZ-FE V6 petrol engine producing 201bhp with 5-speed automatic
  • •SE-L flagship trim introducing electronically controlled height-adjustable air suspension

Common MOT watch-outs

  • !Pitted and corroded rear brake discs due to road grit and under-use
  • !Worn front lower suspension control arm rear bushes causing steering play
  • !Leaking power steering rack seals flagged as fluid leaks
1
Known Issues
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Serious
1
Moderate
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Minor

All Known Issues

Radiator End-Tank Seam Splitting and Coolant Loss

ModerateCooling System

The original Denso radiators fitted to the XU30 series suffer from age-related embrittlement of the plastic side/bottom end tanks and crimped aluminium core seams. In the UK climate, repeated thermal cycling and road salt spray accelerate corrosion along the bottom core channel, leading to slow weeping of Toyota Super Long Life pink coolant. If left unnoticed, the gradual loss of coolant can cause severe engine overheating and cylinder head gasket failure on the 3.0, 3.3, and 3.5-litre V6 engines.

Est. Repair Cost: £350–£700
Warning Signs:

Sweet coolant smell noticeable from the front grille after driving, Gradual drop in engine coolant expansion tank level over several hundred miles, Pink crusted residue or wet staining along the lower radiator tank crimp, Engine temperature gauge creeping above midpoint under motorway load

What to Inspect:
  • Shine a torch through the lower front bumper aperture to inspect the bottom radiator tank for pink crusting
  • Check the coolant expansion tank cold level and verify fluid is clean translucent pink
  • Inspect the under-engine splash shield for dried pink coolant staining or active drips
Verified by IsItAGoodCar Research TeamUpdated

Buying Tips for 2003 Lexus RX (XU30)

  • Confirm the timing belt was replaced on schedule at 100,000 miles or 7 years
  • Check all power equipment including electric tailgate and sunroof operation
2004
Check a 2003 Lexus RX (XU30) by Registration