Reconditioned Turbo Alfa Romeo

1.9 JTD or 2.0 JTDM: two families of Alfa Romeo turbos that don't work the same way?

Yes, and confusing these two generations is the most common ordering mistake. The 1.9 JTD (codes 192, 937, 939) is fitted to the 147, 159 and early Giulietta models, while the 2.0 JTDM (codes 940) powers the more recent Giulietta and Giulia: the turbos used with each differ in geometry, actuator and manufacturer references, and are in no way interchangeable.

Identifying the right turbo: the engine code comes first

Across the range covered here — Giulietta, 147, MiTo, 159 and Giulia — there are more than twenty different engine codes, sometimes for identical engine capacities. A 1.9 JTD 105 hp (code 192A5000) does not take the same turbo as a 1.9 JTD 120 hp (code 937A3000), and a 2.0 JTDM 136 hp (code 939 B3.000) differs from the 2.0 JTDM 170 hp (code 940A4000). The manufacturer reference stamped on the centre housing rotating assembly (CHRA) remains the only reliable starting point; the equivalent references listed in the file (series 71724xxx, 71795xxx, 71796xxx, 55229xxx…) allow you to cross-check several part numbers for the same turbo.

The catalogue also covers petrol engines: 1.4 TB (105, 116 and 120 hp) and 1.4 Turbo MultiAir 135 hp fitted to the MiTo and Giulietta, as well as the 1.3 MultiJet (80, 84 and 95 hp) found on entry-level versions. These fixed-geometry petrol turbos with a wastegate share nothing with the variable-geometry diesel turbos of the JTD and JTDM engines: bearings, sealing and actuator are specific to each family.

Common failure causes on these engines

On high-mileage 1.9 JTD engines, deteriorating lubrication is the primary cause of CHRA failure: dirty oil or overdue oil-change intervals attack the bearings and compromise turbine seal integrity. On the 2.0 JTDM, deposits caused by the EGR circuit and diesel particulate filter build up around the variable-geometry actuator, leading to black smoke, whistling or the engine entering limp mode. Always address the root cause before fitting a new turbo — oil circuit, EGR, DPF — to avoid destroying the replacement part. All turbos listed here are new.