However, thanks to the regular service and high quality motor oil, its service life may increase to 180,000+ miles of mileage (250,000 km). Service life of QR25DE is about 120,000 miles of mileage (200,000 km) at general exploitation by common person. Also thermostat on QR25DE does not have long lifetime, and when it fails, the engine may overheat. It gave a lot of fuel, and burning down in catalytic converter, it promoted its quick destruction.

It happens because of lame soft ECU also. If the engine was produced till 2004, catalytic converter may fail often. Yet the spark plugs may be the reason, perhaps they have expired.Р В РІР‚СњР вЂ™Р’В«esides, QR25DE engine does not start at the temperature below -20 C. It mainly happens because of lame soft ECU, it must be changed. Fuel injectors and throttle body require cleaning.Р В РІР‚СњР СћРЎвЂ™. per 1500 miles (0,5L per 1000 km), then more likely your piston rings have got out of order. Upon changing it, everything will be all right.Р В РІР‚СњР В РІвЂљВ¬. You need to change timing chain and usually it solves the problem completely.Р В РІР‚СњР РЋРЎвЂє. It often happens on the very first generation of the engines. More likely your QR25DE timing chain has stretched. Nissan QR25DEР В РІР‚в„ўР вЂ™Р’В engine problems andР В РІР‚в„ўР вЂ™Р’В malfunctionsР В РІР‚СњР В Р вЂ№. All this has made the engine quite powerful, 250 HP at 5,600 RPM and torque 329 Nm at 3,600 RPM. Besides, 20 HP electro motor was installed on that engine. It uses new pistons and compression ratio is reduced to 9.1. Supercharged QR25DER engine has been produced since 2014. Its compression ratio was increased to 10.7. Specially for JDM Nissan Primera, QR25DD with direct injection system was created. Also camshafts were somewhat updated, redline was raised and some more insignificant novelties happened yet. Intake manifold and pistons were modified, connecting rods were reinforced, balancer shafts were somewhat moved. As it is peculiar to many large 4-cylinder engines, QR25 also has two balancer shafts, which let the engine working smoothly and diminish vibration. This engine does not use hydraulic tappets, so every 60,000 miles of mileage (90,000 km) you should regulate the valves to avoid appearing of irritable ticking noise.Р В РІР‚СњР В РІР‚С›lso QR25DE uses individual ignition coils and electronic throttle body. It is DOHC with 4 valves per cylinder and continuous variable valve timing system CVTC.

Cylinder block remained the same.Р В РІР‚СњР вЂ™Р’В¬ylinder head is also the same as on QR20DE.

All that let increasing engine displacement to 2.5L. Also the engine has 143 mm connections rods and pistons with dish, their compression height is 32 mm. It is the same as QR20DE, but new crankshaft with piston stroke 100 mm was installed into cylinder block. This engine was developed in 2001 and substituted KA24DE. Nissan QR25DE engine reliability, problems and repair Normal engine operating temperature, Р В Р вЂ Р вЂ™Р’ВР В Р вЂ° (F)

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