What spark plugs does a Mercedes GLS use?

The Mercedes GLS spark plug type varies by year and engine. Newer models (2010+) typically use iridium plugs for longer service life. Older models may use platinum or copper. Check the specs below for your exact year.

How often should I change spark plugs on a Mercedes GLS?

Modern Mercedes GLS models with iridium plugs can go 60,000-100,000 miles between changes. Older models with copper plugs need replacement every 30,000 miles. Replace sooner if you notice misfires, rough idle, or poor fuel economy.

What is the spark plug gap for a Mercedes GLS?

Most Mercedes GLS models use a spark plug gap between 0.039" and 0.044" (1.0-1.1mm). Pre-gapped plugs from the OEM are recommended. Do not re-gap iridium-tip plugs as it can damage the electrode.

Can I upgrade to iridium spark plugs in my Mercedes GLS?

Yes, upgrading from copper or platinum to iridium is generally safe and beneficial. Iridium plugs offer better ignitability, longer life, and improved fuel economy. Just match the correct heat range and gap for your engine.

⚡Spark Plug Type

Mercedes GLS Spark Plug Type

Find the correct spark plug type, gap size, and replacement interval for your Mercedes GLS. Covers all model years with torque specs.

Quick Answer

The Mercedes GLS typically uses iridium or platinum spark plugs. Newer models (2010+) use long-life iridium plugs rated for 60,000-100,000 miles. Check below for your specific year.

2019-2024

Spark Plug TypeIridium (long-life)

Plug Gap0.039" - 0.043" (1.0 - 1.1mm)

Replacement Interval60,000 - 100,000 miles

Torque Spec15 - 22 ft-lbs (check manual)

Quantity4 (inline-4) or 6 (V6)

Notes

→Iridium plugs last longer but cost more — do NOT re-gap iridium plugs
→Use a torque wrench — over-tightened plugs can strip aluminum heads
→Apply a thin coat of anti-seize to threads (unless plug is pre-coated)
→Use a spark plug socket with rubber insert to avoid cracking the ceramic insulator

Shop on Amazon →Full Repair Guide →

2017-2018

Spark Plug TypeIridium (long-life)

Plug Gap0.039" - 0.043" (1.0 - 1.1mm)

Replacement Interval60,000 - 100,000 miles

Torque Spec15 - 22 ft-lbs (check manual)

Quantity4 (inline-4) or 6 (V6)

Notes

→Iridium plugs last longer but cost more — do NOT re-gap iridium plugs
→Use a torque wrench — over-tightened plugs can strip aluminum heads
→Apply a thin coat of anti-seize to threads (unless plug is pre-coated)
→Use a spark plug socket with rubber insert to avoid cracking the ceramic insulator

Shop on Amazon →Full Repair Guide →

Frequently Asked Questions

What spark plugs does a Mercedes GLS use?: The Mercedes GLS spark plug type varies by year and engine. Newer models (2010+) typically use iridium plugs for longer service life. Older models may use platinum or copper. Check the specs below for your exact year.
How often should I change spark plugs on a Mercedes GLS?: Modern Mercedes GLS models with iridium plugs can go 60,000-100,000 miles between changes. Older models with copper plugs need replacement every 30,000 miles. Replace sooner if you notice misfires, rough idle, or poor fuel economy.
What is the spark plug gap for a Mercedes GLS?: Most Mercedes GLS models use a spark plug gap between 0.039" and 0.044" (1.0-1.1mm). Pre-gapped plugs from the OEM are recommended. Do not re-gap iridium-tip plugs as it can damage the electrode.
Can I upgrade to iridium spark plugs in my Mercedes GLS?: Yes, upgrading from copper or platinum to iridium is generally safe and beneficial. Iridium plugs offer better ignitability, longer life, and improved fuel economy. Just match the correct heat range and gap for your engine.

Mercedes GLS Repair Guides

→Mercedes GLS Spark Plug Replacement →Mercedes GLS Ignition Coil Replacement →Mercedes GLS Oxygen Sensor Replacement

Browse all Mercedes guides →Browse all Mercedes GLS guides →

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