Alfa Romeo 2.4 JTDM · Wagon
The 2.4-litre JTDM five-cylinder in the 159, Brera and Spider — 200–210 hp in the strongest version, the most powerful diesel in the Alfa range of its era. 400 Nm of torque pushes the heavy 159 or the Brera Q4 forward with authority. The five-cylinder sound is odd and unmistakeable — neither the clatter of a four nor the smoothness of a six, but something in between. In the Spider with Q4 all-wheel drive, an unusual but practical all-round combination.
Best Diesel Estate
200 hp five-cylinder diesel in the Sportwagon: strong pull, pleasant sound, good chassis. The 159 JTDM Sportwagon is the estate for high-mileage drivers.
Engine Weaknesses 6
The dual-mass flywheel on the 2.4 JTDM wears at high mileage and with short-trip driving.
Symptoms: Vibrations when pulling away, rattling when declutching, rough idle
Soot deposits from EGR coke up the intake manifold. The high-output version of the 2.4 JTDM (210 hp) is also affected.
Symptoms: Power loss, black smoke, swirl flap risk
DPF clogs with predominantly urban driving. Regular motorway runs are required for regeneration.
Symptoms: Engine warning light, power loss, elevated fuel consumption, limp mode
Identical design issue to 939B1: the O-ring gasket between oil pump and oil sump flange hardens thermally. Brief oil pressure drop after cold start. Known at Alfa but not officially communicated. Aluminium O-ring as permanent fix.
Symptoms: Brief oil pressure warning tone after cold start (approx. 3 seconds), then normal operation
The swirl flap system of the 2.0 JTDm 939A9 shares the structural problem of all JTDm variants. EGR soot deposits cause flaps to stick; linkage bushes wear out. Blanking kit or revised manifold as permanent solution.
Symptoms: Engine warning light, power loss, stumbling in the lower rev range
The alternator on the 2.0 JTDm shows bearing wear and freewheel failure at higher mileages. Documented in Alfisti Forum for the 2.0 JTDm Brera/159. Replacement is labour-intensive due to tight packaging.
Symptoms: Whistling at certain rev ranges, battery drain while driving, battery or alternator warning light
Vehicle Weaknesses 12
Front and rear subframes rust without adequate corrosion protection. Rust on front wings and sills is an exclusion criterion when buying. Front and rear subframes can show significant rust that is expensive to repair.
The M32 gearbox (Fiat/GM design) develops bearing noise in 5th and 6th gear from around 100,000 km due to excessive bearing preload. The small bearing behind 6th gear wears preferentially. Gearbox overhaul without removal costs approximately 1,100 €.
Front and rear subframes rust through due to inadequate factory underbody sealing. The plastic undertray traps moisture. After 6–10 years structural corrosion is often found on the subframes and ECU brackets.
The M32 six-speed gearbox (shared with Opel/Fiat) has undersized bearings in the cover for 5th and 6th gear. From approx. 80,000–110,000 km the gearbox howls at motorway speeds. Without repair, total failure is likely.
The steering rack on early Brera models (up to 2007) leaks and produces knocking and squealing noises. Front upper and lower wishbone joints wear early and announce themselves with creaking. Revised from the 2008 model year.
The 939 Spider boot takes on water after prolonged rain. A leaking hood compartment seal and porous rear seals allow ingress. Boot wiring loom can be damaged by moisture.
On the Brera 939 the air conditioning compressor develops a loud circular-saw noise from the engine bay when the compressor bearing wears. Refrigerant leaks accelerate bearing wear. Compressor replacement including system flush for metal swarf is required: 600–1,200 €.
On the Brera 939 rear springs can break, especially on vehicles driven heavily on poor roads. In addition, front upper and lower wishbones wear. Broken springs are a safety hazard and result in immediate MOT failure.
The Brera's tail lights take on moisture, leading to short circuits and bulb failure. Expensive to replace at approximately 450 € per unit. Checking the seals when buying a used example is advisable.
Rear lights on the 939 Spider draw in moisture through hairline cracks in the seal between the outer lens and housing. Condensation collects inside the light unit and causes corrosion of the sockets and short circuits.
The electric seat adjustment on the Brera 939 fails. The seat adjustment motor or drive mechanism wears out. Spare parts are hard to find for this discontinued model. Repair by specialists or used parts is recommended.
The brake discs on the Brera 939 (especially rarely driven examples) rust quickly and develop deep scoring from embedded rust. Ventilated sport discs rust particularly badly on their flanks. Typical on used cars with low usage.
Reports & Tests
The Brera shares its platform and many weak points with the 159. Rust on the front crossmember due to dirt accumulation between the seal and the component is a known issue, as are electrical failures and steering rack leaks on early build years up to 2007.
