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Manufacturing, design, and assembly flaws
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1 a, K+ [5 r0 ^7 i- BThe QR25DE sold in the United States has been subject to a significant number of problems in its short lifetime. A variety of mechanical flaws have led to numerous technical service bulletins, recalls, repairs, and outright engine replacements.
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* Vehicles with the QR25DE may ingest material from a damaged pre-catalyst resulting in increased oil consumption.[7]6 i) J8 a4 M k0 [
* Power valve screws in the intake manifold may become loose and result in unstable idling or power loss.[8]2 `5 f$ ?$ H7 {$ |8 z g
* In June 2006, it came to Nissan's attention that approximately 85,000 Altimas and 2,000 Sentra SE-Rs equipped with the QR25DE and built between January and May 2006 may experience unusually high oil consumption. This can lead to premature engine failure and possibly a fire. While Nissan investigates the problem, owners of the affected vehicles are being advised to check their oil frequently (every 700 mi (1,100 km) [1127 km]), and dealers have been instructed to place the affected vehicles on sales hold.[9]. Y8 Y. Z. F4 z3 y* P
- R5 a, \% p% X0 k[edit] Stated versus observed power5 l) G% } m# y" b8 F# V/ a H& y
4 t$ ?4 r' z( O3 g/ \( [In addition to the physical problems suffered by the QR25DE, Nissan's official stated power and torque numbers seem to disconnect from power measurements taken by the general public. Though rated for 177 hp (132 kW) and 172 ft·lbf (233 N·m) of torque in the Nissan Altima and Sentra SE-R, the actual power of the engine may be significantly lower. Multiple dynamometer readings performed by a range of people in an assortment of cars over several years have shown that the engine more than likely produces ~160 hp and ~170 ft·lbf of torque. Parasitic loss alone seems an unlikely candidate for the discrepancy as automatic transmission loss would be approximately 28% and manual transmission loss 19%.[10][11]
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However, engine dyno tests performed by Brian Crower, a respected aftermarket parts supplier, shows this engine does indeed perform very close to the advertised numbers. The high weight of the Helical Limited Slip differential which is in many models with this engine, and the very heavy dual mass flywheel likely account for the losses on traditional chassis dynos. |
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