Nissan 5.6 V8 VK56DE Engine Reliability, Specs And Problems

The Nissan VK engine (previously called the ZH) is a V8 piston motor, featuring an aluminum dual overhead camshaft with four valves.

Actually, VK56 was built on the framework of the brand’s VQ V6 motor but not VH V8, applied for Q45/Cima vehicles. Among the main differences are a variable intake manifold of polymer, restyled heads, and a better drive of the wire throttle chamber. Intake manifold routes air in different directions depending on the engine speed. It helps to enhance low-end torque or high-end horsepower.

Nissan 5.6 V8 VK56DE Specs

The breakdown of the engine code is as follows:

• VK – Engine Family
• 56 – 5.6 Liter Displacement
• D – DOHC (Dual Overhead Camshafts)
• E – Multi-Point Fuel Injection

The manufacture VK56DE was launched in 2003 as the power unit for the Nissan Armada car, sold in the United States. Being an American product, this 5.6L motor has more compact modifications, VK45DE and VK50VE.

Though VK56DE has much in common with VK45DE, they differ in some aspects. Thus, the height of the cylinder block rose to 232 mm while the bore became 98 mm (in comparison with 93 mm in the original version).

The motor keeps connecting rods of 154.2 mm along with fresh pistons able to diminish the compression index to 9.8. Consequently, the engine turned out to be a more classically torquey V8 and became a great option for pickups, SUVs, and some other big vehicles.

With aluminum cylinder heads, featuring 4 valves per cylinder and 2 camshafts, this motor keeps an intake camshaft with a Continuous Variable Valve Timing Control system (shortly CVTCS). While the engine is provided with hydraulic lifters, timing chains remain on its blind side.

VK56VD is another modification of the motor. It features more advanced technologies, using a direct injection fuel system, a variable valve timing system on two camshafts along with Variable Valve Event and Lift system.

Nissan VK56DE Engine Oil Capacity

The Nissan 5.6 VK56DE engine requires 6.9 quarts of 5W-30 oil with a filter replacement.

What Cars Have A VK56DE?

• Infiniti M56/Q70
• Infiniti QX56/QX80
• Nissan Pathfinder
• Nissan Patrol
• Nissan Armada
• Nissan NV
• Nissan Titan

VK56DE Cylinder Head

Durable but light aluminum alloy, the cylinder head is made of, provides it with great cooling efficiency. While the original motor lacked valve timing control system, the intake camshafts of its new variation feature Continuous Variable Valve Timing Control, which permits variable valve timing to respond to motor redline and throttle opening.

Meanwhile, the advanced control and the lowered system friction contribute to better reaction and advanced torque specifications. Two chains control the camshafts.

The timing chain conveys the rotating movement from the crankshaft to the intake and exhaust camshafts.

The diameter of the intake valve is 37.0 mm (1.45 inches) while the exhaust valve is 31.2 mm (1.22 inches). The intake duration for the motor without CVTC is 230 degrees and 232 degrees for the one featuring it. The exhaust duration for CVTC is 244 degrees while it’s 232 degrees for the engine without it. VK56DE isn’t equipped with hydraulic tappets and, consequently, the valve clearance is regulated by specific valve lifters.

Nissan 5.6 V8 VK56DE Problems And Reliability

1. Motor uproar. It is usually caused by the stretched timing chain. It’s important to take care of it as such trouble may emerge even if the vehicle hasn’t run too much. If you face this problem, replace the timing chain plus the high-pressure fuel pump in order to avoid the emergence of any malfunctions in the future. Be ready that this procedure will be pretty pricy as in order to replace the timing chain, it’s necessary to disassemble the car’s front.
2. Rough idle and decreased output. Like in VQ35, this trouble is caused by worn-out catalytic converters due to fuel of low quality. Consequently, the motor absorbs the dust, which abrades the cylinder walls and later reaches the oil system before spreading all over the motor. Bad news: the only way out is to acquire a brand new engine. However, in countries, which have poor quality gasoline, the problem is resolved by mounting high flow catalytic converter plus ECU reflash.
3. Decreased efficiency and bad dynamics. The basic reason is the dysfunction of the fuel pump. And if the situation deteriorates, it’s the right time to buy a fresh pump.

The first VK56DE motors featured unreliable AC condenser radiator cooling fan, which could jam and lead to overheating. Moreover, it’s crucial to wash the radiator every year as the clean one is less prone to overheating, which leads to cylinder head gaskets destruction. Furthermore, it’s advisable to replace the high-pressure fuel pump after 50,000-60,000 miles (80,000-90,000 kilometers) are run as it’s not very durable.

You may also face the deformation of filter bodies, which results in dust and other small litter getting stuck in the motor and causing its malfunction.

Having faced the erratic idling speed trouble, cleaning of the throttle body may help to get rid of it. It’s advisable to do that every 60,000-70,000 miles (100,000-120,000 kilometers). Be ready that radiator leakage may happen after 120,000 miles (200,000 kilometers) are run.

In order to avoid these troubles, try to use the fuel and engine oil only of high quality. Moreover, it’s advisable to replace oil on a regular basis and serve the vehicle on time.

The information provided in this article is for general informational purposes only. The author and publisher make no representations or warranties of any kind, express or implied, regarding the accuracy, adequacy, validity, reliability, availability, or completeness of any information presented. The reader is advised to consult a qualified professional, such as a mechanic or dealership, before making any decisions related to their vehicle's engine oil or maintenance.