About the Nissan Navara D21

The D21 generation was the successor to the Datsun "720". The providers used the term "Datsun" from 1980-1981 after that renamed itself "Nissan" starting aided by the 1982 model year line of trucks and cars alike. However, the Nissan pickups continued to be marketed in the Japanese home market as the "Nissan Datsun". The D21 series happened to be unofficially called Nissan Hardbody within the United says.The truck's term, "Hardbody", pertains to its double-wall bed and overall styling. The Hardbody was released for the U.S. Market from 1986.5 until 1997, and were direct competition to the Toyota compact pickup. The move from the 720 to the D21 Nissan series body style updated mid-year 1986.5 so the new 'D21' 1986.5 and later Hardbody can easily be distinguished from the earlier 720 body style by its two large headlights rather than four smaller lights and a less boxy, more aggressive appearance. The Nissan Pathfinder was based from the Hardbody Truck and launched in the same model year with chassis code WD21.Within the US, the Hardbody taxi designs happened to be 'Standard' and 'King' (also recognized as 'Extended'). Sleep measures were 'standard' 6-foot (2 m) and 'long' seven feet. Global markets also received the 'Crew Cab' (4-door) variation with a brief four and a semi feet sleep.

4-cylinder and V6 engines were available, aided by the 2.4L 4-cylinder KA24E being a respectable-performance SOHC engine that replaced the Z24i for 1990–1997 with a new 3-valve-per-cylinder head. The 6-cylinder 3.0L VG30i (early years) or VG30E (further years) engine increased power and torque only modestly and was unavailable within the US starting with the 1996 unit spring because Nissan was not capable to meet up with in energy the needs of the new OBD-II emissions law.Five-speed, including overdrive, hands-on transmissions were one particular popular, but an automatic transmission was an available option. Both rear-wheel-drive (4x2) and four-wheel-drive (4x4) versions were made in quantity. A limited slip differential was traditional regarding the peak 'SE' trim 4WD variants.

Major options supplied air conditioning, heavier wheels/tires, sliding rear windows, stereo, and rear bumper. There were several trims available such as starting point, XE, and top of the line SE. The XE could be ordered with a 'value package' starting in 1994 which supplied air conditioning, power mirrors, alloy wheels, and chrome on body trim such as the mirrors and bumpers. The SE was healthier equipped and could be ordered with the "sport power package" with sunroof, power windows, locks, and mirrors, air conditioning and special "Robot" alloy rims.In 1993, Nissan had a strange model year crossover which got the dashboard of the 1986.5–1992 model years with a slightly refreshed body appearancan along with some little indoor changes and a revised instrument panel. In a first for the car business, this unit utilized the unique R134A air conditioning refrigerant.

1994 would be the last major refresh through 1997. A new ergonomic dashboard and much improved interior arrived.1995 was the first model to conform aided by the new US, Division of Transportation "high mount brake light" regulation necessitating all trucks to have a brake illumination within the center of the rear during the top of the taxi.In 1996, a driver's side airbag was added as really as compliance because of the new US OBD-II emissions law. Rear wheel ABS emerged with both 2WD and 4WD models start in 1991.

Versions sold in other countries came with a host of a lot more affordable engines, ranging from 1.6-litre gasoline fours up to a 2.7-litre diesel four-cylinder, including SD25 and TD25 diesel engines.Complete Bosch four-sensor (all-wheel) ABS would not feel available until the "new" 1998 D22 show, "Frontier" pickups were released to the general public.These low-cost, dependable Hardbody little pickup trucks sold very really internationally, and tend to be even often seen both on-road and off-road. These are typically well known for their reliability and endurance, because of the exception of figure panel and frame rust over time. Other stuff to search for are really a noisy timing company in the 1990–1997 KA24E (2.4) 4cyl engine in certain which had a issue with the stock timing chain guides and slippers deteriorating, breaking off and allowing the timing chain to damage the timing cover, seizing the chain to the engine and/or timing cover, along with damaging pistons and bending valves requiring serious engine work in extreme cases. This was remedied by buying aftermarket system timing parts, (particularly the chain manual, slipper and tensioner), and repairing immediately when noises became apparent. Alternatively, the KA24E was an excellent engine. The V6 engine had a timing belt that requires replacing every 60K miles. Exhaust manifold studs were well known to fail prematurely due to heat embrittlement from poor components high quality, on all years from 1986.5- 1995. In the US, starting in 1998, the new "D22" was officially called, "Frontier" and utilized a new DOHC 2.4 4cyl borrowed from the Nissan Altima. A recently modified "VG33" V6 was available in improvement to the new 2.4 4cyl beginning in 1999 and ending production in the US in 2004. The unique VG33E V6 had new, heavier, 10 mm exhaust manifold studs in an try to lower the risk of premature exhaust manifold stud failing, but still had limited success. The truck was used by Jeremy Clarkson on the top Gear for crossing the The english language Channel in 2007 with an outboard motor connected to the lower back.

In general however, the VG30E and VG33E V6's were both amazingly legitimate engines.The D22 is truly still being made in South Africa and elsewhere in the world.The D21 design was however available new in some Latin American countries, created in Mexico until the 2008 model year. In its current home country a number of four basic variations of the D21 are sold together as the Nissan Camiones (literally "Nissan Trucks").Nissan Mexicana completed production of the Camiones on March 15, 2008 after 15 a very long time of manufacturing in the Cuernavaca plant.The Nissan Hardbody is nevertheless staying sold in Venezuela as the D21.

Nissan Navara D21 ute/truck engine factory workshop and repair manual 1986-1997 Download

### Leaf Spring Replacement on a Nissan Navara D21 (1997)

#### Tools Required

- **Jack and Jack Stands**
- **Usage**: To lift the vehicle safely and securely. The jack raises the vehicle, while jack stands provide support to prevent it from falling.
- **How to Use**:
- Position the jack under the vehicle's frame.
- Pump the jack handle to lift the vehicle.
- Once raised, place jack stands under the frame and lower the vehicle onto them.

- **Socket Set**
- **Usage**: To remove and tighten bolts and nuts. Usually, a 10mm, 12mm, and possibly larger sizes are needed.
- **How to Use**:
- Select the correct size socket for the bolts.
- Attach the socket to the ratchet handle.
- Turn counter-clockwise to loosen and clockwise to tighten.

- **Wrench Set**
- **Usage**: To access bolts that are hard to reach with a socket.
- **How to Use**:
- Choose the appropriate wrench size.
- Fit it over the nut and turn counter-clockwise to loosen.

- **Pry Bar**
- **Usage**: To help remove leaf springs from hangers or to pry components apart.
- **How to Use**:
- Insert the pry bar between the leaf spring and the mounting point.
- Apply pressure to lift or separate components.

- **Rubber Mallet**
- **Usage**: To gently tap components without damaging them.
- **How to Use**:
- Use the mallet to lightly tap on bolts or parts that are stuck.

- **Torque Wrench**
- **Usage**: To ensure bolts are tightened to the manufacturer's specifications.
- **How to Use**:
- Set the torque wrench to the specified torque.
- Use it like a regular ratchet, but stop when you hear a click indicating the correct torque is reached.

- **Safety Glasses and Gloves**
- **Usage**: To protect your eyes and hands during the replacement process.
- **How to Use**:
- Wear them at all times while working on the vehicle.

#### Parts Required

- **New Leaf Springs**
- **Why Replacement is Required**: Old or damaged leaf springs can affect the vehicle's ride height, handling, and load-carrying capacity.
- **What to Look For**: Inspect for cracks, rust, or sagging. If any damage is found, new leaf springs are necessary.

- **Bushings**
- **Why Replacement is Required**: Worn bushings can lead to excessive movement and noise. Replacing them ensures a snug fit and smoother operation.
- **What to Look For**: Check for cracks or wear on the rubber bushings.

- **U-bolts**
- **Why Replacement is Required**: Old U-bolts may corrode or stretch, compromising safety. New U-bolts ensure a secure attachment of the leaf springs.
- **What to Look For**: Inspect for rust or deformation.

#### Steps to Replace Leaf Springs

- **Preparation**
- Park the vehicle on a flat surface and engage the parking brake.
- Gather all tools and replacement parts.

- **Lifting the Vehicle**
- Use the jack to lift the rear of the vehicle and place jack stands for safety.

- **Removing the Old Leaf Springs**
- Remove the rear shackle bolts using the socket set or wrench.
- Remove the U-bolts using a socket.
- Use the pry bar to help detach the leaf spring from the front mount and the shackle.
- Carefully lower and remove the old leaf spring.

- **Installing New Leaf Springs**
- Position the new leaf spring in place.
- Attach the front mount first, then the rear shackle.
- Insert and tighten the new U-bolts over the leaf spring and axle.

- **Final Checks**
- Use the torque wrench to ensure all bolts are tightened to the manufacturer’s specifications.
- Double-check that everything is secure.

- **Lowering the Vehicle**
- Carefully remove the jack stands and lower the vehicle using the jack.

- **Test Drive**
- Take a short drive to ensure everything is functioning correctly and listen for any unusual noises.

#### Additional Tips
- **Consult the Vehicle Manual**: For specific torque specifications and part numbers.
- **Work Slowly and Carefully**: Take your time to avoid mistakes and ensure safety.
rteeqp73

Tools / materials (minimal list)
- Basic mechanic’s tools, jack stands, engine support or hoist, torque wrench
- Drill, spot-weld cutter or grinder, cutting disc, body saw
- MIG or TIG welder, wire brush, grinding discs
- Replacement strut tower patch panels or steel plate (3–4 mm), plug-weld plugs
- Primer, seam sealer, underbody coating, rust inhibitor
- New fasteners / strut top nuts, new strut mount bearing if worn
- Protective gear (welding helmet, gloves, respirator)

Safety note (brief): support vehicle securely, disconnect battery before welding, relieve suspension load before removing strut.

Ordered procedure with theory (each step explains why and how it fixes the fault)

1) Diagnose and map the damage
- What to do: Inspect the strut tower visually from engine bay and wheel well; look for cracks, rust-through, delamination of metal, stretched bolt holes, and distortion of the tower flange. Tap with a hammer to find thin metal. Check alignment symptoms and strut top play.
- Theory: The strut tower is a load path that takes suspension vertical loads into the body. Corrosion or cracking breaks that load path and allows the top of the strut to move relative to the body, causing noise, misalignment and accelerated wear. Mapping shows the true extent of structural loss so you restore full load-bearing metal, not just cosmetic rust.

2) Prepare vehicle and relieve loads
- What to do: Support vehicle on stands, remove wheel, support lower suspension arm and/or use spring compressor if strut will be disassembled. Support engine/accessories if needed for access.
- Theory: You must remove or neutralize loads so the strut and body don’t shift while you remove, cut, and weld. Welding or clamping distorted metal without correct support will produce incorrect geometry and weak joints.

3) Remove strut assembly and surrounding components
- What to do: Remove the upper strut nuts, detach brake lines, ABS sensors, swaybar links etc. Take out the strut (or at least remove strut top mount/insulator) so you can access tower.
- Theory: The strut must be out (or free) to weld safely and to allow measurement and final reassembly. Removing the assembly prevents heat damage to internals and ensures you can re-seat the strut mount precisely onto solid metal.

4) Cut out all unsound metal
- What to do: Cut back to solid, clean steel; remove rusted, crazed, or thin sections including around bolt holes and any crack tips. Remove spot welds where an inner reinforcement panel is compromised.
- Theory: Welding new steel to contaminated or thin metal creates weak overlaps and hidden corrosion pockets. Proper repair removes compromised material so the new patch carries the load directly into healthy structure.

5) Prepare and fit replacement patch / reinforcement
- What to do: Fabricate or fit OE-style patch panels or a double-skin reinforcement plate that matches the original contours and bolt flange. Make sure bolt holes align or are reamed to correct size. Fit inner and outer layers as required with tight gaps for plug welding.
- Theory: The tower must recreate the original geometry and stiffness. A patch that reproduces the original thickness and mounting flange restores the correct load path and distributes suspension loads into the surrounding body structure. Reinforcing plates restore stiffness and prevent local deformation under load.

6) Tack and weld in sequence to control distortion
- What to do: Clamp patches in place, tack weld, then stitch or plug weld around the panel in a balanced pattern (opposite sides alternated) to avoid drawing the metal. Use short welds and allow cooling; grind welds flush if necessary. Restore any internal seam welds.
- Theory: Welding heats steel and causes shrinkage; an uncontrolled continuous weld will pull and deform the tower, changing suspension geometry. Balanced short welds restore continuity while minimizing distortion. Plug welds recreate original spot-weld points that transfer shear loads through the layers.

7) Rebuild mounting face and bolt holes
- What to do: Re-drill/ream the strut top bolt holes to the correct position and diameter. If the flange is replaced, ensure the strut top sits flat on the flange—use shims or weld fillets to recreate original seating plane.
- Theory: Accurate bolt-hole location and a flat seating face are critical so the strut’s bearing and mount transmit loads evenly. Off-centre or angled seating reintroduces preload, noise, and misalignment.

8) Corrosion protection and sealing
- What to do: Clean welds, coat bare metal with etch primer, seam-seal welded joints, undercoat and rustproof inside cavities if possible. Recreate rain/engine-bay flashings.
- Theory: The original failure was likely driven by corrosion. Proper sealing and protection prevent moisture intrusion and halt recurrence. Seam sealer restores the moisture barrier between panels.

9) Reinstall strut assembly, torque and preload correctly
- What to do: Refit the strut and mount, replace worn top mount bearing or nuts, torque upper nuts and other fasteners to factory specs, reattach lines and sensors. If the strut was compressed, verify spring preload and orientation.
- Theory: Correct torque and proper preload ensure the strut and mount behave as intended; loose or over-tightened tops can cause bearing failure, noise, or altered suspension geometry. Replacing worn components prevents immediate re-failure at the repair site.

10) Final checks: alignment, test drive, inspect for leaks/noise
- What to do: Do a full wheel alignment, road-test for clunks, measure toe/camber, and re-inspect welds and sealant after first heat cycles.
- Theory: Alignment verifies that the repair restored the original geometry and that load paths are correct. Test driving under real loads reveals any residual issues missed in static inspection.

How the repair fixes the fault (concise theory)
- Restores continuous load path: Replacing rusted/cut steel and welding in new panels restores the structural route that carries suspension loads from the strut into the body. Without that continuous metal, loads concentrate at small areas causing deformation and noise.
- Recreates stiffness and geometry: A properly fitted and welded patch reproduces the tower’s original stiffness so the suspension operates with the designed kinematics; this prevents abnormal camber/toe and uneven tire wear.
- Prevents recurrence: Removing all corroded metal and sealing welded seams eliminates the corrosion source and moisture traps that started the failure.
- Replaces compromised fastenings: Re-making the flange and bolt holes and using new mount hardware prevents slop and re-cracking at the interface.

Common pitfalls to avoid (short)
- Welding over thin/rusted metal — creates hidden weak joints.
- Not re-establishing the exact seating plane — causes bearing preload and geometry errors.
- Full continuous welding without sequence control — warps tower.
- Skipping corrosion protection — guarantees repeat failure.

Done.
rteeqp73

### Engine Diagnostics on a Nissan Navara D21 (1997)

#### Overview of Engine Diagnostics
Engine diagnostics involves checking the engine's performance to identify issues. It helps ensure the engine runs efficiently, meets emissions standards, and prevents expensive repairs.

#### Components of Engine Diagnostics

1. **OBD-I System (On-Board Diagnostics)**
- **Purpose**: Monitors engine performance and emissions.
- **Components**:
- **ECU (Engine Control Unit)**: The brain of the engine, it processes data from various sensors and controls engine functions.
- **Sensors**: Collect data about engine conditions (e.g., temperature, air/fuel mixture).
- **MAF (Mass Air Flow) Sensor**: Measures air entering the engine.
- **O2 (Oxygen) Sensors**: Monitor exhaust gases to optimize fuel mixture.
- **Coolant Temperature Sensor**: Indicates engine temperature for proper fuel management.

2. **Diagnostic Connector**
- **Purpose**: Connects to diagnostic tools to read codes.
- **Location**: Usually found under the dashboard near the steering column.

3. **Diagnostic Tools**
- **OBD-I Scanner**: Reads codes and provides data from the ECU.
- **Multimeter**: Measures voltage and resistance for electrical issues.
- **Compression Tester**: Checks engine cylinder compression.

#### Theory Behind Engine Diagnostics
The engine operates on a delicate balance of air, fuel, and spark. If any component fails or performs poorly, it can lead to:
- Decreased fuel efficiency
- Increased emissions
- Engine misfires

Just like a conductor ensures all musicians in an orchestra play in harmony, the ECU ensures all engine components work together efficiently.

#### Steps to Perform Engine Diagnostics

1. **Visual Inspection**
- **Check for Leaks**: Look for oil or coolant leaks under the engine.
- **Inspect Belts and Hoses**: Ensure they are not cracked or worn.

2. **Connect Diagnostic Tool**
- **Locate the Diagnostic Connector**: It’s usually a 16-pin connector.
- **Plug in the OBD-I Scanner**: Turn the ignition to the ON position without starting the engine.

3. **Read Diagnostic Codes**
- **Follow Scanner Instructions**: Access stored trouble codes (DTCs).
- **Interpret Codes**: Look up codes in the service manual to identify issues.

4. **Check Sensor Functionality**
- **MAF Sensor**: Use a multimeter to check voltage and resistance.
- **O2 Sensors**: Check voltage output while the engine is running.
- **Coolant Temperature Sensor**: Measure resistance at different temperatures to ensure it’s functioning correctly.

5. **Perform a Compression Test**
- **Remove Spark Plugs**: To prevent engine damage.
- **Insert Compression Tester**: In each cylinder and crank the engine.
- **Read the Pressure**: Compare readings to manufacturer specifications.

6. **Test Drive**
- **Monitor Performance**: Pay attention to any abnormal sounds, vibrations, or warning lights.

#### Common Issues and What Can Go Wrong
- **Faulty Sensors**: Can give incorrect readings, leading to poor fuel economy and performance.
- **Wiring Issues**: Damaged wires or connectors can lead to intermittent problems.
- **Vacuum Leaks**: Can cause a lean mixture, resulting in misfires and rough idling.
- **Engine Overheating**: Caused by a faulty coolant temperature sensor, leading to severe engine damage.

#### Conclusion
Engine diagnostics on a Nissan Navara D21 involves checking various components to ensure the engine runs smoothly. Regular diagnostics help catch problems early, preventing costly repairs and keeping the engine performing optimally. By understanding how the system works and what can go wrong, you can become a more proficient mechanic.
rteeqp73