Reference specification for glow plugs and the cold start system on Land Rover diesel engines – from the classic Tdi to the modern Ingenium. Covers type, voltage, replacement intervals and common faults.
Land Rover diesel engines use ceramic or metal sheathed glow plugs rated at 11–12V, with typical resistance between 0.5–1.5Ω. The cold start system pre‑heats the combustion chamber to aid starting in low temperatures. Most modern Land Rovers use fast‑glow (4–6 second) plugs controlled by the ECU based on coolant temperature and engine speed.
Full specification table, common mistakes and verification steps below.
This table lists glow plug specifications for major Land Rover diesel engines. Always confirm the exact type and resistance range for your engine code and model year before ordering replacement parts.
| Engine Code | Glow Plug Type | Voltage | Resistance (Ω) | Replacement Interval |
|---|---|---|---|---|
| 200Tdi | Metal sheathed (standard) | 12V | 0.8–1.2 [PLACEHOLDER] | 60,000 mi / as required |
| 300Tdi | Metal sheathed (standard) | 12V | 0.8–1.2 [PLACEHOLDER] | 60,000 mi / as required |
| TD5 | Ceramic (fast glow) | 12V | 0.6–1.0 [PLACEHOLDER] | 60,000 mi |
| 224DT (2.2 Duratorq) | Metal sheathed (fast glow) | 11V | 0.5–0.9 [PLACEHOLDER] | 70,000 mi |
| 276DT (2.7 TDV6) | Ceramic (fast glow) | 12V | 0.5–0.8 [PLACEHOLDER] | 80,000 mi |
| 306DT (3.0 SDV6) | Ceramic (fast glow) | 12V | 0.5–0.8 [PLACEHOLDER] | 80,000 mi |
| 368DT (3.6 TDV8) | Ceramic (fast glow) | 12V | 0.5–0.8 [PLACEHOLDER] | 80,000 mi |
| 448DT (4.4 SDV8) | Ceramic (fast glow) | 12V | 0.5–0.8 [PLACEHOLDER] | 80,000 mi |
| 204DTD (Ingenium D) | Ceramic (fast glow) | 12V | 0.5–0.7 [PLACEHOLDER] | 80,000 mi |
| AJ20D6 (3.0 I6 Diesel) | Ceramic (fast glow) | 12V | 0.5–0.7 [PLACEHOLDER] | 80,000 mi |
Figures marked [PLACEHOLDER] require confirmation against the OEM workshop manual for the specific engine and year. We have flagged these deliberately rather than guessing.
Glow plugs are only part of the cold start system. The glow plug relay, engine coolant temperature sensor, and ECU logic all play a role. On modern Land Rovers, the glow plugs are often used for post‑heating (after the engine has started) to reduce emissions and improve idle stability during warm‑up.
The typical pre‑glow time varies from 1–2 seconds in warm weather to 10–15 seconds in very cold conditions. If the glow plug light flashes or fails to illuminate at all, check the relay and the coolant temperature sensor – a faulty sensor can prevent the glow plugs from activating even when the ambient temperature is low.
For older Tdi engines, glow plugs are simpler but still critical. A failed glow plug on a 200Tdi or 300Tdi will cause hard starting and white smoke on cold mornings. Always replace glow plugs in full sets – mixing old and new plugs can cause uneven heating and potential cylinder damage.
The simplest way to test glow plugs is with a multimeter. Disconnect the wiring harness and measure resistance between the terminal and the engine block (or the plug body). A reading within the spec range (typically 0.5–1.5Ω) indicates a good plug. An open circuit (infinite resistance) means the plug has failed internally.
You can also test the power supply to the glow plugs. With the ignition on and the engine cold, measure the voltage at the glow plug harness – it should be around battery voltage (11–12V) for the pre‑glow period. If there is no power, check the relay and the coolant temperature sensor.
For a visual inspection, remove the glow plug and inspect the heating element. If the tip is swollen, damaged, or covered in heavy carbon, replace it. Always cross‑reference the plug type with your engine code using our Engine Code Decoder before ordering replacements.
The typical interval is 60,000–80,000 miles [PLACEHOLDER], but many specialists recommend replacing them earlier if you experience cold start issues. Always replace in sets.
Hard starting in cold weather, white smoke from the exhaust on startup, a flashing glow plug warning light, and increased idle roughness until the engine warms up.
Yes – measure the resistance at the harness connector with a multimeter. A good plug will show low resistance (0.5–1.5Ω). An open circuit indicates a failed plug.
Common causes include carbon fouling from poor combustion, electrical overload (relay failure), and physical damage (swelling or cracking). Cheap aftermarket plugs are also prone to premature failure.
Yes, but cold starts will be difficult, and the engine may run poorly until warm. Prolonged driving with failed glow plugs can stress the battery and starter motor.
Every Figure Sourced – unverified numbers flagged, never guessed.
Last Verified March 2026 – reviewed on a regular schedule.
12 Vetted JLR Specialists – real workshop insight behind the caveats.
100% Independent – no sponsors, no manufacturer influence.
If you're struggling with cold starts or suspect faulty glow plugs, our vetted specialist network can diagnose and advise on the right solution.
COMPARE QUOTES NOW USE THE DIAGNOSTIC WIZARD →