Alfa Romeo 1.9 JTDM
The 1.9-litre JTDM with 120 hp is the entry diesel in the 159 — underpowered for the heavy car, but frugal. Torque is sufficient for relaxed cruising; for brisk overtaking manoeuvres the reserves fall short. Multijet injection for smooth running, DPF issues with mainly short-trip use.
Entry-Level Diesel in the Heavy 159
120 hp 1.9 JTDM in the heavyweight 159 — feels underpowered. Economical yes, but the 159's chassis deserves more power under the bonnet.
Engine Weaknesses 6
EGR recirculation cokes up the intake manifold. Swirl flap breakage can lead to engine damage. Particularly problematic with short-trip driving.
Symptoms: Power loss, black smoke, limp mode, possible swirl flap failure
VTG turbocharger clogs with soot deposits from short-trip driving. Vane ring jams, unstable boost pressure and engine warning light.
Symptoms: Power loss, unstable boost pressure, engine warning light
The dual-mass flywheel wears especially with frequent short-trip driving. Typical cost for clutch and flywheel: 1,000–2,000 €.
Symptoms: Vibrations when pulling away, rattling when declutching
The actuator linkage bushes on the 1.9 JTDm 16V swirl flap system wear out. Flaps can drop into the cylinders. EGR coking accelerates wear. Blanking kit as permanent solution; revised manifold (55210201) as an upgrade.
Symptoms: Engine warning light P2279/P2075, power loss, stumbling, elevated fuel consumption
The 1.9 JTDm 16V EGR cooler leaks internally and allows coolant into the exhaust duct. Problem identical to 939A4/939A. A bypass pipe test is possible before an expensive replacement.
Symptoms: White smoke briefly after cold start, coolant loss without oil-water mix
The glow plug relay on the 1.9 JTDM fails at high temperatures or through aging. Cold-start problems in winter result. Relay replacement is inexpensive and can easily be done as a DIY job, provided no glow plugs are simultaneously affected.
Symptoms: Difficult cold start in winter, long pre-glow cycle without success, engine warning light, rough running after cold start
Vehicle Weaknesses 8
The front subframe (engine cradle), rear axle carrier and sills rust without adequate factory protection. Particularly on TI models, areas behind trim panels corrode unnoticed. Subframe replacement costs approximately 1,000 € plus fitment.
The M32 gearbox (fitted to 1.9 JTDM and 1.9 JTS) develops bearing noise from around 100,000–190,000 km. Gearbox overhaul without removal costs approximately 1,100 €. Conversion to the more robust F40 gearbox is possible.
On the 159 and Brera 939, multiple electronic components can fail simultaneously: windows, air conditioning, Bose audio, xenon, door control units. A faulty body computer is the frequent cause. Replacement 800–2,000 €.
Control arm bushes and joints on the 159 front axle wear noticeably. A visual inspection at the time of purchase is recommended. At the end of their service life, pronounced knocking is clearly audible. Plan for renewal every 100,000–150,000 km.
The steering rack on 159 models up to 2007 tends to leak with squeaking and clicking noises when turning. A revised steering rack was fitted from the 2008 model year. A leaking rack puts stress on the hydraulic power steering.
The 159 cooling system (especially the 2.4 JTD) tends to develop air pockets, especially after repairs. Several bleed points must be observed. Symptoms: coolant boils over, heating only works at higher revs.
The 159's air conditioning regularly loses refrigerant through stone chip damage to the condenser or leaking connections. Correct fill quantity is 550 g — frequently only 490 g is added. Leaks are only visible via UV tracer after several days.
The brake discs on the 159 (especially the Spider variant) rust heavily after just 4 days of standing. Grinding and juddering occur when pulling away. After approximately 10 km the braking feel normalises, but disc wear remains elevated.
Reports & Tests
Only around 58.5 percent of seven-year-old Alfa 159s pass their MOT at the first attempt — a noticeably worse result than comparable German rivals. Diesel engines in particular cause significant problems up to and including total engine failure. Brake discs and suspension wear above average.