Volvo XC90

The GM automatic gearbox used in the XC90 T6 was not originally designed for the full torque of the B6294T. Gearbox failures on early 2003–2005 models are documented.

Symptoms: Shifting problems, gearbox slips, gear selection refused, gearbox oil leak, harsh jerking when changing gear.

Camshaft adjusters frequently leak oil. Timing belt should be changed every 100,000 km. A break causes costly valve damage. Combination of a leaking adjuster and an old belt is common.

Symptoms: Oil patch at top of engine, camshaft fault code, rough engine running, check engine light.

The B6294T water pump is driven via an auxiliary drive shared with the power steering pump. The bearing can fail at high mileage, causing coolant loss. Repair time approximately 3 labour hours.

Symptoms: Squealing or grinding from engine block, coolant loss, rising engine temperature

The oil feed strainer to the B6294T turbocharger can block, interrupting oil supply to the turbo shaft. Without sufficient oil, the shaft runs dry and the turbocharger is irreparably damaged in a short time.

Symptoms: Loud screaming or rattling from turbo, power loss, blue smoke, metal particles in oil

Water pump and cooling fan control are prone to failure. The six-cylinder runs hot and tolerates overheating poorly — head gasket damage is a risk.

Symptoms: Coolant temperature rises, fan runs continuously or fails, coolant loss, heater delivers cold air.

The B6294T PCV diaphragm tears with age and allows oil mist to escape into the intake tract. Besides elevated oil consumption, catalytic converter clogging is a risk. Repair: membrane alone takes approx. 15 min; replacing the whole box is preferred.

Symptoms: Hissing noise on cold start warm-up, elevated oil consumption, oil in air filter housing

The Aisin Warner AW55-50/51SN gearbox in the XC90 I is regarded as its biggest weakness: from 100,000 km it shifts harshly and with unusually long gear-change intervals. Valve body faults often require a complete transmission overhaul.

The Haldex all-wheel drive system on early XC90 models (pre-2007) shows wear at the coupling and differential. If the damage is not corrected, the entire drivetrain can fail.

The optional air suspension compressor on the XC90 I overheats or freezes in sub-zero temperatures. Moisture in the compressor and pipes freezes at around -5°C and blows the fuse. Repair at the dealer around €1,600.

On the XC90 I, tie rod ends (especially outer), ball joints and control arms at the front axle wear out. This leads to wheel misalignment and heavy one-sided tyre wear. Replace early to avoid consequential damage.

The front subframe behind the radiator is known for corrosion, especially on vehicles from road-salt regions. Visible rust on the subframe requires treatment and sealing (€600+).