When Should Spark Plugs and Glow Plugs Be Replaced on a Toyota Land Cruiser 200?
Toyota Land Cruiser 200 Series Facelift 2
Toyota Land Cruiser 200 Series Facelift 2•
•57 views
The Land Cruiser 200 was sold with several engines, so the engine code must be identified first. The 4.0-litre 1GR-FE petrol V6 uses six spark plugs, while the 4.6-litre 1UR-FE petrol V8 uses eight. The 4.5-litre 1VD-FTV diesel V8 relies on compression ignition: it has no spark plugs, but it does use eight glow plugs—one for each cylinder.
Spark plugs and glow plugs: what is the difference?
The two components support combustion and starting in different ways. A petrol spark plug repeatedly creates an electrical spark. A diesel glow plug heats the combustion area before starting and may remain active briefly after the engine fires.
| Parameter | Spark plugs | Glow plugs |
|---|---|---|
| LC200 engines | 1GR-FE 4.0 V6; 1UR-FE 4.6 V8 | 1VD-FTV 4.5 V8 Diesel |
| Quantity | 6 on 1GR-FE; 8 on 1UR-FE | 8 — one per cylinder |
| Main function | Ignite the petrol-air mixture with a spark | Assist diesel ignition during starting |
| Operating period | Throughout petrol-engine operation | Before starting and, when required, after starting |
| Service approach | Scheduled replacement plus fault diagnosis | Condition- and code-based checks; no universal interval |
| Typical fault | Electrode wear, wider gap or cracked insulator | Open circuit, abnormal current or a control-circuit fault |
When should the system be checked?
Symptoms differ by engine type. Petrol-plug faults are often more obvious under load; glow-system faults usually show up during starting and the first few seconds of running. Hot weather can mask one weak glow plug.
Signs of a spark-plug problem
- a Check Engine light and misfire codes for one or more cylinders;
- rough or unstable idle and noticeable vibration;
- hesitation, jerking or a delayed response to the accelerator;
- higher fuel consumption without a clear change in route or load;
- extended cranking or an unburned-fuel smell.
Ignition coils, injectors, intake leaks, wiring and low compression can produce the same symptoms. Read fault codes and live data before ordering parts.
Signs of a glow-plug problem
- longer cranking after the vehicle has been parked;
- uneven diesel operation for a few seconds after starting;
- whitish smoke and an unburned-fuel smell immediately after start-up;
- a stored pre-heating circuit fault code;
- several starting attempts when ambient temperature is lower.
Even a healthy glow-plug set cannot compensate for weak batteries, a worn starter, low fuel pressure, injector faults or poor compression.
How the 1VD-FTV glow system works
Each of the 1VD-FTV's eight combustion chambers has its own heating element. Electronic control sets the operating time according to temperature and starting conditions. Diagnosis therefore covers the plugs, power supply, control module, wiring, connectors and relevant sensor inputs.
High ambient temperature reduces the demand for pre-heating and can conceal a partial failure. The fault may become obvious after an overnight stop, in cooler weather or when battery voltage falls. The absence of a fixed replacement line does not make the plugs lifetime parts.
What shortens plug life?
Petrol engines
- unsuitable fuel or an excessively rich or lean mixture;
- engine oil or coolant entering the combustion chamber;
- overheating, the wrong plug type, incorrect gap or torque;
- a damaged coil, boot, connector or plug insulator;
- moisture, oil or sand in a spark-plug well.
1VD-FTV diesel
- control-module, power-circuit or connection faults;
- unstable voltage or overheating of the heating element;
- deposits that affect heat transfer and removal;
- a replacement part with the wrong electrical characteristics;
- careless removal of a slender plug from an older cylinder head.
What happens if service is delayed?
- A petrol plug's gap grows, forcing the ignition coil to generate more voltage.
- Misfires appear and driveability, fuel economy and smoothness deteriorate.
- Unburned fuel can overheat the catalytic converter.
- On the diesel, one failed element may cause a brief rough start.
- Several failed plugs increase cranking time and the load on the batteries and starter.
- If the module or wiring is defective, replacing only the plugs will not fix the cause.
Land Cruiser 200 schedule and specifications
The table combines official manual specifications with service guidance.
| Parameter | 1GR-FE petrol 4.0 V6 | 1UR-FE petrol 4.6 V8 | 1VD-FTV diesel 4.5 V8 |
|---|---|---|---|
| Part type | Spark plugs | Spark plugs | Glow plugs |
| Quantity | 6 | 8 | 8 |
| Service reference | Replace at 100,000 km* | Replace at 100,000 km* | No universal fixed interval; inspect by condition |
| Manual specification | DENSO SK16HR11 | DENSO SK20HR11 | Select the part number by VIN and specification |
| Gap | 1.1 mm; do not adjust | 1.1 mm; do not adjust | Not applicable |
| Check sooner if | Misfires, hard starting or damage | Misfires, hard starting or damage | Hard starting, rough start-up or a circuit code |
* 100,000 km is the service reference for the applicable LC200 versions. The owner's manual confirms the Denso types and gap; the maintenance schedule must be verified for the individual market, model year and VIN.
How to read the table
- The 1GR-FE and 1UR-FE use different plugs even though the nominal gap is the same.
- The manual specifies iridium-tipped plugs and states that the 1.1 mm gap must not be adjusted.
- Cylinder count determines quantity: six for the V6 and eight for either V8.
- The petrol interval does not apply to the 1VD-FTV glow system; diagnose it first.
Choosing the correct parts
For a petrol engine, the exact Denso designation in the manual—or the corresponding genuine Toyota part—is the safest starting point. Matching threads and appearance are not enough: reach, seat, heat range, resistance and electrode design must all be correct.
Select 1VD-FTV glow plugs by VIN. LC200 market specifications, emissions versions and superseded part numbers changed over its long production run, while visually similar plugs may have different heating characteristics. The generation and engine can first be reviewed in the Toyota Land Cruiser catalogue, but the final part number must come from the parts catalogue for the individual VIN.
Diagnosis: plug fault or something else?
Before dismantling anything, preserve the DTCs, freeze-frame data and operating conditions. Then match the symptom to the engine type and test the complete related circuit.
| Engine and symptom | Possible plug link | Other likely causes | First step |
|---|---|---|---|
| Petrol: Check Engine and misfires | Electrode wear, wider gap or cracked insulator | Coil, injector, wiring or compression | Read DTCs, freeze frame and misfire counters |
| Petrol: hesitation under load | Insufficient spark energy at higher pressure | Fuel delivery, intake, coil or sensors | Check loaded data before clearing faults |
| Diesel: extended cranking | One or more elements do not heat | Batteries, starter, fuel or compression | Check codes, voltage and system current |
| Diesel: white smoke after start | One cylinder warms more slowly | Injector, fuel pressure or compression | Compare cylinders with electrical measurements |
| Diesel: glow-circuit code | Open circuit or abnormal plug reading | Module, connector, supply or wiring | Test the circuit to the repair procedure |
| Any version: hard starting | The relevant plug type may contribute | Battery, starter, sensors or fuel | Begin with a scan and basic power check |
What is checked in the glow system?
- stored codes and the conditions in which they were set;
- battery voltage and cranking speed;
- power, grounds, connectors, wiring and the control module;
- each plug's resistance or current using the Toyota procedure;
- variation between cylinders and whether the fault returns.
Do not apply full battery voltage directly to a removed glow plug of unknown specification; its control voltage may be different. Expected resistance is very low, so meter accuracy, plug temperature and contact quality affect the result.
Practical pre-service checklist
- Identify the VIN, engine code, model year and original market.
- Save DTCs, freeze-frame data and live parameters before clearing faults.
- For a petrol version, confirm plug designation, quantity and service interval.
- Work on a cool engine; clean the wells and keep sand out of the cylinders.
- Replace petrol spark plugs as a complete set using Toyota's procedure and torque.
- On the diesel, test the plugs, supply, wiring and control module as one system.
- Assess seizure risk before removal: a slender glow plug can break in the cylinder head.
- After reassembly, rescan, verify starting and record mileage and part numbers.
Mistakes to avoid
- Applying the petrol 100,000 km interval to the 1VD-FTV glow system.
- Replacing glow plugs without checking the supply, module and wiring.
- Ordering parts by engine capacity or a photograph without checking the VIN.
- Manually altering the gap of fine iridium electrodes.
- Testing an unknown glow plug with direct full battery voltage.
- Overtightening threads in the aluminium head or using unapproved lubricant.
- Clearing faults before saving DTCs and freeze-frame data.
Frequently asked questions about glow plugs
Should all eight plugs be replaced if one has failed?
Test every plug and the common circuit first. Whether to replace one element or the set depends on the readings, the condition of the remaining plugs, mileage, access and the risk of repeating the labour.
Why does the diesel start normally despite a stored fault?
Hot weather reduces the need for pre-heating, so a partial failure may be hard to notice. Diagnose the code anyway: cooler conditions or lower battery voltage can expose the problem.
Can the dashboard pre-heat lamp confirm system health?
No. The lamp reflects the control strategy, not the condition of every plug, the module and the wiring. A sound conclusion requires codes and measurements from the repair procedure.
Are glow plugs still needed in a hot climate?
Yes. They remain part of the starting-control system. High ambient temperature merely shortens heating time and may hide a fault until an overnight stop, cooler season or voltage drop.
Conclusion
The 1GR-FE Land Cruiser 200 uses six DENSO SK16HR11 spark plugs; the 1UR-FE uses eight DENSO SK20HR11 plugs. For both specifications, the manual gives a non-adjustable 1.1 mm gap. The 1VD-FTV diesel uses eight glow plugs, which must be diagnosed together with the module and wiring. Always confirm the exact schedule and part numbers by VIN, original market and vehicle documentation.
