Hyundai Trajet
Tough two-litre NA from the Sirius family. Simple tech, trouble-free as long as the oil gets changed on schedule.
Reliable workhorse, full stop
The Trajet moves families from A to B without fuss. That is the entire pitch.
Engine Weaknesses 7
The Sirius G4JS engine uses interference timing belt drive. Change interval: 90,000 km. Many used vehicles are on the road with an overdue belt.
Symptoms: Engine suddenly no longer starts; no compression; possible crunching on failure.
The G4JS Sirius II is an interference engine — if the timing belt fails, pistons contact valves and bend them. One documented case showed belt failure after 34,000 km of a newly installed belt, with 8 bent valves.
Symptoms: Sudden engine stop without warning, then no restart, no compression in affected cylinders
Older Sigma/Delta V6 engine tends to oil leaks at valve cover gaskets and camshaft seals at high mileage. Labour-intensive disassembly due to the tight V6 packaging.
Symptoms: Oil stains under the vehicle, oil smell, dropping oil level.
Older Sirius engines develop increased oil consumption from piston ring wear from around 130,000 km. Coked oil control rings are typical with extended change intervals.
Symptoms: Oil level drops 1–2 L per 5,000 km; light blue smoke; oil smell in the engine bay.
The belt-driven water pump in the G4JS can fail before the timing belt. Simultaneous replacement of both components is mandatory to avoid duplicate labour costs.
Symptoms: Coolant loss; elevated engine temperature; squealing from the belt area.
After a timing belt failure and valve damage on the G4JS, oil consumption frequently rises from damaged piston rings or a poorly executed engine rebuild — sometimes 3–4 litres per 1,000 km.
Symptoms: Blue smoke from the exhaust, dropping oil level after timing belt repair, reduced compression pressure
The G4JS valve cover gasket ages and leaks. Oil then drips onto the timing belt and significantly accelerates its degradation — an often-overlooked connection that leads to premature belt failure.
Symptoms: Oil stains under the vehicle in the engine bay, burning smell after driving, oil visible on timing belt cover
Vehicle Weaknesses 4
Critical weakness: rear axle rusts precisely at the spring seat. Control arms and trailing arms cost around 500 € per side. In Germany partially covered by Hyundai recall/goodwill.
The diesel manual gearbox suffers from worn synchroniser rings, leading to stiff or crunching gear changes in certain gears. A gearbox overhaul becomes necessary.
ABS sensor rings on the axles corrode and break. Broken segments migrate and trigger severe pedal kickback and ABS activation just before standstill.
Front strut top mounts wear prematurely on the Trajet — up to three replacements may be needed by 127,000 km. Components are undersized for the vehicle weight.