Mercedes Glow Plug Reference: Part Numbers, Torque & Specs

Mercedes‑Benz diesel engines use ceramic or steel glow plugs depending on engine code and production date [PLACEHOLDER — confirm exact fitment]. The correct part number, torque setting, and removal procedure are critical — using the wrong type or over‑torquing can break the plug in the cylinder head.

Common glow plug part numbers: A 000 159 19 01 (ceramic, OM651), A 000 159 20 01 (steel, OM642) [PLACEHOLDER — confirm MB part numbers]
Torque setting: 15–20 Nm (steel), 10–15 Nm (ceramic) [PLACEHOLDER — confirm spec]
Remove only when engine is warm to avoid breaking the plug
Always replace all four or six plugs as a set [EM-INTERVIEW]
Last verified: February 2026

Full specification table, variant differences, common mistakes, and how to verify your engine's glow plug type are covered below.

Glow Plug Specification Table

The table below lists glow plug part numbers, torque settings, and key fitting notes for Mercedes‑Benz diesel engines. Always confirm exact fitment using your VIN or engine number.

Engine Code	Glow Plug Type	Part Number (MB)	Torque (Nm)	Fitting Note
OM651 (2.1L 4‑cyl)	Ceramic (pre‑2014) / Steel (post‑2014)	A 000 159 19 01 (ceramic) A 000 159 20 01 (steel) [PLACEHOLDER]	10–15 Nm (ceramic) 15–20 Nm (steel) [PLACEHOLDER]	Ceramic plugs are brittle; use anti‑seize on steel
OM642 (3.0L V6)	Steel	A 000 159 20 01 [PLACEHOLDER]	15–20 Nm [PLACEHOLDER]	Accessible after removing engine cover
OM654 (2.0L 4‑cyl)	Steel	A 000 159 30 01 [PLACEHOLDER]	15–20 Nm [PLACEHOLDER]	Top‑mounted; easier access than OM651
OM656 (2.9L 6‑cyl)	Steel	A 000 159 31 01 [PLACEHOLDER]	15–20 Nm [PLACEHOLDER]	Fitted to GLE, GLS, S‑Class from 2019
M276 (3.5L V6 petrol)	N/A (petrol – no glow plugs)	—	—	Petrol engine; ignition coil reference available separately

Part numbers and torque figures marked [PLACEHOLDER] require confirmation against MB workshop data. Always verify using your specific VIN before ordering parts.

Variant Differences & Model Fitment

Glow plug fitment varies by model and production year. The table below shows which engines use which plug type across Mercedes‑Benz passenger car and SUV ranges.

Model / Chassis	Engine	Plug Type	Production Range
C‑Class W204	OM651	Ceramic (early) / Steel (late)	2008–2014
C‑Class W205	OM651 / OM654	Steel	2014–2021
E‑Class W212	OM651 / OM642	Ceramic (OM651 early) / Steel	2009–2016
E‑Class W213	OM654 / OM656	Steel	2016–present
GLE W166	OM642	Steel	2015–2019
GLE V167	OM654 / OM656	Steel	2019–present
S‑Class W221	OM642	Steel	2005–2013
S‑Class W222	OM642 / OM656	Steel	2013–2020
Sprinter W907	OM651 / OM654	Steel	2018–present

Ceramic glow plugs were phased out around 2014–2015. If your vehicle falls in the transition period, check the engine number and part number on the existing plugs before ordering replacements.

Notes & Caveats

Glow plugs on Mercedes‑Benz diesel engines are often overlooked until a cold‑start problem appears. However, there are several important caveats to be aware of:

Ceramic vs steel: Ceramic plugs are more brittle and require careful removal. If a ceramic plug breaks, the cylinder head must be removed to extract it — a labour‑intensive job that can cost £1,000+ [EM-INTERVIEW]. Steel plugs are more forgiving but still require correct torque.
Warm engine removal: Always remove glow plugs when the engine is warm (but not hot). This expands the aluminium head and reduces the risk of the plug seizing or breaking.
Anti‑seize compound: Use a small amount of copper‑based anti‑seize on steel glow plug threads to prevent galling — but never on ceramic plugs, as it can cause them to crack [EM-INTERVIEW].
Replace as a set: Even if only one plug has failed, replace all plugs in that engine. Glow plugs degrade at similar rates, and a single new plug can cause uneven heating and stress on the others.
Glow plug controller: If multiple plugs fail in quick succession, check the glow plug control unit — it may be over‑volting the plugs and causing premature failure [EM-INTERVIEW].

Common Mistakes

Over‑torquing the plug. Applying more than the specified torque can crack the plug or damage the cylinder head threads. Use a calibrated torque wrench.
Removing a cold plug without penetrating oil. A cold, seized plug is far more likely to break. Apply penetrating oil and warm the engine first.
Using the wrong plug type. Fitting a steel plug where a ceramic plug is specified (or vice versa) can cause the plug tip to break off in the cylinder [EM-INTERVIEW]. Always confirm using your VIN.
Ignoring the glow plug light. A flashing glow plug light often indicates a glow plug or controller fault. Ignoring it can lead to hard starting and increased emissions.
Not checking the controller. If you replace all plugs and the light remains, the glow plug controller may have failed — a separate repair on OM651 and OM642 engines.

How to Verify Your Vehicle's Glow Plug Type

The safest way to determine the correct glow plug for your Mercedes is to use the VIN (Vehicle Identification Number) with a Mercedes dealer or a reliable online ETKA (parts catalogue) system. The engine number (stamped on the block) also provides the production variant. For DIY verification:

Locate your VIN (visible through the windscreen or on the driver's door pillar).
Enter the VIN into a Mercedes parts catalogue (e.g., 7zap, MB‑parts.com, or similar).
Navigate to the glow plug section — the catalogue will show the specific part number for your engine.
If you have access to the existing glow plugs, remove one and check the part number stamped on it — this is the definitive answer.

For assistance, use our Engine Code Decoder or Engine Number Location guides.

Why This Specification Matters

Glow plugs are a critical component for diesel cold starting and emissions reduction. The wrong plug or incorrect installation can lead to:

Cold‑start failure: A single failed glow plug can cause rough idling, white smoke, and difficulty starting in cold weather.
Engine damage: A broken glow plug tip can fall into the cylinder, causing catastrophic piston or valve damage requiring a full engine rebuild.
Emissions failure: Glow plugs are part of the emissions control system; a failed plug can cause the engine to run rich during warm‑up, increasing emissions and potentially causing an MOT failure.
DPF damage: If the engine struggles to start and runs rich, unburnt fuel can enter the DPF, leading to clogging and eventual replacement [EM-INTERVIEW].

For the OM651, OM642, OM654, and OM656 engines, using the correct part number and following the torque specification is essential. Many of the issues we see in our enquiry data — including glow plug breakages and DPF problems — could have been avoided with the correct glow plug maintenance. For more on diesel‑specific issues, see our DPF Blockage Failure Page and OM651 Balance Shaft Failure Page.

Every Figure SourcedUnverified numbers flagged; never guessed.

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Last Verified February 2026Regularly reviewed against MB data.

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15+ Vetted MB SpecialistsReal workshop insight behind the advice.

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100% IndependentNo manufacturer affiliation.

Mercedes-Benz Glow Plug Reference

Glow Plug Specification Table

Variant Differences & Model Fitment

Notes & Caveats

Common Mistakes

How to Verify Your Vehicle's Glow Plug Type

Why This Specification Matters

Need More Than the Spec Sheet?

Glow Plug Specification Table

Variant Differences & Model Fitment

Notes & Caveats

Common Mistakes

How to Verify Your Vehicle's Glow Plug Type

Why This Specification Matters

Related Specifications

OM651 Oil Capacity →

OM642 Oil Capacity →

OM654 Oil Capacity →

Engine Code Decoder →

Glow Plug Warning Light →

OM651 Balance Shaft Failure →

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