Engine: 2.5 dCi YD25 (DIQW25) Turbo model: GT2056V (Variable Geometry Turbo – VNT) The GT2056V turbocharger fitted to the Nissan 2.5 dCi YD25 engine is designed for high torque and 4WD performance. However, due to heavy towing, off-road use, high mileage, and EGR-related carbon buildup, turbocharger wear or failure may occur.
Common Symptoms of Turbocharger Failure
1. Loss of Engine Power
Sluggish acceleration
Weak or delayed boost pressure
Poor performance under load or towing
2. Excessive Exhaust Smoke
Blue smoke – oil leaking through worn turbo seals
Black smoke – insufficient air supply or boost leak
White smoke – oil entering exhaust side
3. Unusual Turbo Noises
High-pitched whistling or siren sound
Grinding or metallic noise (damaged bearings or shaft)
4. Increased Oil Consumption
Frequent oil top-ups required
Oil traces inside intercooler hoses
5. Boost Control Problems
Underboost or overboost fault codes
Check engine light
Limp mode activation
6. Variable Geometry (VNT) Issues
Sticking vanes due to soot buildup
Irregular or delayed turbo response
Inconsistent boost pressure
7. Excessive Shaft Play
Radial or axial movement of turbo shaft
Risk of turbine or compressor wheel contact with housing
Common Causes of Turbo Failure
Poor oil quality or extended oil change intervals
Blocked oil feed or return lines
Carbon buildup from EGR system
Heavy-duty driving (towing, off-road)
Improper engine shutdown after high load
Recommendation
If your Nissan NP300 Navara D40 or Pathfinder R51 2.5 dCi (171–174 HP) shows any of the above symptoms, immediate inspection of the turbocharger and lubrication system is recommended. Continued driving with a faulty turbo can lead to severe engine damage or complete turbo failure.