326-4700
326-4700 Caterpillar 320D C6.4 Injector: 095000-5341 Specs
326-4700, 10R-7673, 326-4701, 326-4702, 321-3600095000-5341 Valve AssemblyDLLA152P9471800 barProduct Overview
The Caterpillar 326-4700 (Denso 095000-5341 / 095000-5342, Caterpillar Reman 10R-7673) is the primary original equipment common rail fuel injector engineered for Caterpillar 320D, 320D L, 320D LN, 321D LCR, and 323D hydraulic crawler excavators powered by the 6.4-liter Cat C6.4 ACERT turbocharged diesel engine. Built on the heavy-duty Denso G2 common rail platform operating at injection rail pressures up to 1800 bar, this injector utilizes precision hole-type nozzle DLLA152P947 (internal Denso assembly 093400-9470) to deliver micro-metered pilot, main, and post-injection events tailored for Tier 3 / Stage IIIA emissions compliance. In severe earthmoving and mining applications, fuel contamination and abrasive fine particulate ingress lead to command piston seat erosion and nozzle needle micro-scoring. Typical workshop failure symptoms include excessive dynamic fuel backleak return, long cranking when hot, black smoke under heavy hydraulic dig cycle loading, cylinder cutout diagnostic codes, and unburned fuel dilution in the engine oil pan.
Crucial Workshop Notice: The Caterpillar 320D C6.4 fuel system requires strict 30-digit QR trim code calibration entered into the ECM via Caterpillar Electronic Technician (CAT ET) upon injector replacement. Operating without trim code entry results in cylinder power imbalance, audible diesel knock, and increased fuel dilution.
Vehicle & Engine Fitment
| Vehicle | Engine | Years |
|---|---|---|
| Caterpillar 320D / 320D L Hydraulic Excavator | Caterpillar C4.4 / C6.4 / C6.6 ACERT & Perkins 1104D / 1106D | 2006-2015 |
| Caterpillar 320D LN / 320D LRR Compact Excavator | Caterpillar C4.4 / C6.4 / C6.6 ACERT & Perkins 1104D / 1106D | 2006-2015 |
| Caterpillar 321D LCR Reduced Radius Excavator | Caterpillar C4.4 / C6.4 / C6.6 ACERT & Perkins 1104D / 1106D | 2006-2014 |
| Caterpillar 323D / 323D L Hydraulic Excavator | Caterpillar C4.4 / C6.4 / C6.6 ACERT & Perkins 1104D / 1106D | 2006-2014 |
Technical Specifications
| Specification | Value |
|---|---|
| SKU | 326-4700 |
| Brand | CATERPILLAR / DENSO |
| Type | Complete Common Rail Injector Assembly (Denso G2 CRS) |
| OE Number | 326-4700, 10R-7673, 326-4701, 326-4702, 321-3600 |
| Denso Part Number | 095000-5341, 095000-5342, 095000-5340 |
| Control ValveCore Spec | |
| Nozzle CodeCore Spec | |
| Internal Nozzle P/NCore Spec | |
| Injection System | Caterpillar Common Rail System (Denso G2) |
| Operating PressureCore Spec | |
| Torque Spec | 30 N·m (22 lb-ft) |
| Hold Down Torque | 30 N·m (22 lb-ft) |
| Fuel Pipe Union Torque | 35-40 N·m (26-30 lb-ft) |
| Warranty | 12 Months |
| Emission Standard | EPA Tier 3 / EU Stage IIIA |
| Engine Family | Caterpillar C6.4 ACERT (6.4L) |
| Coding Required | Yes (30-digit QR Trim Code via CAT ET) |
Installation Tips
Tools needed: Caterpillar Electronic Technician (CAT ET) diagnostic software with Comm Adapter 3, 17mm & 19mm flare nut crowfoot wrenches for fuel rail line unions, Calibrated torque wrench (10 N·m - 100 N·m range), Caterpillar injector bore cleaning brush kit and industrial vacuum, Micrometer or depth gauge for copper sealing washer thickness inspection (1.5mm - 2.0mm), Clean fuel line protective blanking plugs (Denso 14mm thread)
- De-energize & Relieve Residual Pressure: Shut down the machine, isolate the master battery disconnect switch, and verify fuel rail pressure has bled down below 10 bar before loosening any fuel hydraulic joints.
- Engine Bay Wash & Well Decontamination: Clean the rocker cover perimeter and injector well recesses using solvent degreaser and high-pressure air blast to eliminate dust, sand, and dried mud contamination.
- Remove Rocker Cover & High-Pressure Fuel Lines: Remove the cylinder head valve cover and disconnect high-pressure injection pipes using a 17mm flare nut wrench; immediately cap all open rail ports and injector inlet cones.
- Extract Hold-Down Clamp & Injector Body: Back out the hold-down clamp retaining bolt and extract the injector vertically. If carbon bonded in the sleeve, use an approved slide-hammer tool without twisting the body.
- Retrieve Old Washer & Ream Injector Seat: Confirm the old annealed copper washer is extracted from the cylinder head pocket; ream the bottom seat face until completely flat, bright metal free of carbon pits.
- Fit New Copper Washer & Anti-Seize: Mount a brand new OEM-specification copper seal washer onto the nozzle shaft using high-temperature assembly grease; apply a micro-film of ceramic anti-seize paste to the injector body barrel.
- Torque Hold-Down Clamp to Specification: Seat the injector squarely into the cylinder sleeve, install the hold-down clamp, and torque the clamp bolt to 30 N·m (22 lb·ft) with a calibrated torque wrench.
- Install High-Pressure Supply Lines: Finger-thread the fuel pipe union nuts to ensure perfect thread alignment, then torque the pipe nuts to 35-40 N·m (26-30 lb·ft).
- Reassemble Spill Rail & Rocker Cover: Reconnect fuel spill-off return rail lines with new O-rings, install the rocker cover with a new gasket, and reconnect electrical solenoid terminal nuts to 2.0 N·m.
- Program 30-Digit QR Trim Code via CAT ET: Connect Caterpillar Electronic Technician to the machine service connector. Under 'Service -> Calibrations -> Injector Code Calibration', input the 30-digit alphanumeric QR calibration code engraved on the injector head into the designated cylinder register.
- Prime Fuel System & Start Engine: Prime the fuel system with the electric lift pump until clear fuel returns to tank, start the engine, and execute an ECM cylinder cutout test to verify combustion balance.
- MANDATORY CAT ET CALIBRATION: Never run the excavator without registering the 30-digit QR trim code into the ECM. Uncalibrated injectors trigger delivery variance up to 12%, causing cylinder knock and accelerated piston crown wear.
- COPPER CRUSH WASHER DISCARD: Always replace the copper sealing washer with a genuine CAT specification part. Reusing a crushed washer causes combustion gas blowby ('black death') and overheats the nozzle needle.
- HOSPITAL-GRADE FUEL CLEANLINESS: Denso G2 precision tolerances are under 2 microns. A single particle of quarry dust will seize the internal command piston or score the valve seat.
- PRECISE TORQUE CONTROL: Over-torquing the clamp bolt beyond 30 N·m will deform the injector body, causing internal needle binding and severe misfire.
Frequently Asked Questions
Does Caterpillar 320D injector 326-4700 require ECM coding with CAT ET?
Yes, Caterpillar injector 326-4700 requires mandatory cylinder-specific QR code calibration. Each injector is factory tested on an automated bench, and its individual flow performance matrix across pilot, pre-, main, and post-injection pressures is encoded into a 30-digit alphanumeric trim code stamped on the solenoid top. This code must be programmed into the engine ECM using Caterpillar Electronic Technician (CAT ET) under the 'Injector Code Calibration' menu. Failing to program this code results in rough engine idle, elevated smoke emissions, and cylinder delivery imbalance.
What are the common symptoms of a failing 326-4700 injector on a Cat C6.4 engine?
The most frequent symptoms include prolonged cranking or hard starting when the engine is warm (caused by high dynamic backleak fuel return bleeding rail pressure), excessive black smoke during heavy boom up or bucket crowd hydraulic loads, engine hunting/surging at high idle, active diagnostic trouble codes for cylinder misfire (MID 036 / CID 0001-0006), and unburnt fuel entering the crankcase oil causing rising engine oil levels.
Is 326-4700 interchangeable with Caterpillar 320-0680 or 10R-7672?
No. While both are used in Caterpillar 20-ton excavators, they belong to different engine families and fuel injection architectures. Part number 326-4700 (095000-5341) is a Denso G2 common rail injector engineered specifically for the 6.4-liter Cat C6.4 ACERT engine in standard 320D machines. In contrast, 320-0680 (10R-7672 / Perkins 2645A747) is used on 320D2 and 320D Series machines equipped with the Cat C6.6 ACERT or Perkins 1106D engine. Their physical nozzle lengths, hold-down clamp offsets, and ECM fuel maps are completely different.
Why does a hot Cat C6.4 engine stall or fail to restart when injectors are worn?
Hot diesel fuel exhibits significantly lower kinematic viscosity than cold fuel. As the internal command piston and control valve seat inside the Denso injector wear beyond allowable micro-tolerances, high-pressure fuel escapes into the return rail instead of building nozzle chamber pressure. During starter cranking (200-250 rpm), the high-pressure supply pump cannot generate the minimum 250-300 bar rail pressure required for the ECM to trigger injection, causing a no-start condition until the engine cools down.
What is the recommended service life and preventative maintenance for 326-4700 injectors?
Under normal quarry and construction conditions with clean, high-grade fuel, 326-4700 injectors deliver a typical service life of 6,000 to 8,000 operating hours. To achieve this longevity, replace the primary fuel water separator (10 micron) and secondary fuel filter (2 micron) every 500 hours using genuine Caterpillar High Efficiency filters, drain fuel tank water sumps daily, and test fuel samples regularly for water emulsion or abrasive silica contamination.
Diagnostic Trouble Codes & Fault Protocols
Common diagnostic trouble codes (DTCs) triggered when this common rail injector experiences wear, circuit faults, or calibration drift:
Fuel Rail / System Pressure Too Low
Excessive internal backleak from worn control valve seats drops common rail pressure below target under engine load.
Injector Circuit Malfunction / Open Circuit
Solenoid coil resistance drift (0.2-0.5 Ω) or piezo stack degradation triggers driver stage shutdown on affected cylinders.
Cylinder Misfire & Balancing Deviation
Carbon-clogged nozzle spray holes or missing IMA calibration causes uneven cylinder contribution. Recode ECM and verify washer seating.
Fuel Rail / System Pressure Too High
Spill line backpressure or stuck metering valve prevents rail depressurization, creating overpressure risks under load.
Cross-Reference & Compatibility
Sister parts, same-platform variants, and known incompatibilities.
Technical Diagnostic & Service Protocols
Authoritative field procedures, diagnostic testing thresholds, and service SOPs for this assembly.