NGK 4853 PFR7B Double Platinum Spark Plug Box of 4 Audi S4 S6 BMW Alpina B7

The NGK 4853 PFR7B Double Platinum Spark Plug is a laser-welded, fine-wire platinum plug engineered for the 1991 Audi 200, 1992-1994 Audi S4, 1995-1997 Audi S6, 1997 Volvo 850, and 2007-2008 BMW Alpina B7. Running an M14 x 1.25 thread, 19mm reach, and a factory pre-set gap of 0.028 in (0.7mm), 4853 delivers platinum-grade ignition reliability rated to 70,000-90,000 miles. Heat range 7 makes this plug one step colder than the standard OEM PFR6B, making it the correct choice for modified or higher-output versions of these engines. Each order of 4853 includes four plugs with pre-installed crush washers. Made in Japan.

Double Platinum Technology

• Laser-welded dual platinum electrodes: A fine-wire 1.0mm platinum center electrode and a platinum-tipped ground electrode work together to maintain a stable spark gap over the full service life, reducing the wear-driven misfire that plagues conventional nickel plugs.
• 98% pure copper core: The copper core dissipates combustion heat faster than nickel alloy cores, keeping electrode temperature in the optimal ignition zone and preventing pre-ignition under boost or high-load driving.
• Pure alumina silicate ceramic insulator: Rated for superior dielectric strength, the insulator resists thermal shock, prevents flashover via corrugated ribs, and transfers heat efficiently away from the firing tip.
• Trivalent metal plating on the shell: A triple-layer anti-corrosion and anti-seize coating makes installation and future removal cleaner, even after years of heat cycling in aluminum cylinder heads.
• Cold-rolled threads: Cold rolling work-hardens the thread form, reducing the chance of thread cross-threading or galling during installation in aluminum heads common on Audi, Volvo, and BMW platforms.
• Triple seals: Three-stage sealing between the insulator and shell prevents combustion gases from leaking past the plug body, protecting the ignition system and maintaining cylinder pressure.
• Mid-projection firing tip: The 3.5mm projected platinum tip reaches deeper into the combustion chamber for faster flame kernel propagation, cleaner combustion, and better cold-start behavior.
• 5k Ohm resistor built in: The integrated 5,000-Ohm resistor suppresses ignition noise, protecting sensitive OBD-II electronics and eliminating RF interference in modern engine management systems.

Heat Range 7 vs. Heat Range 6 Which Plug Do You Need?

NGK's heat range numbering works on a simple scale: higher number = colder plug. A colder plug transfers combustion heat away from the firing tip faster, which protects against pre-ignition and tip erosion in high-output or modified engines. A hotter plug retains more heat to self-clean fouling in stock, lower-load applications.

The 4853 (PFR7B, Heat Range 7) sits one step colder than the PFR6B (Stock 3500, Heat Range 6), which is the OEM heat range for most naturally aspirated and stock-turbocharged applications in this plug family. If your Audi S4, S6, or 200 Quattro is chipped, running a tune, or otherwise making more power than factory spec, 4853 is the correct selection. For a completely stock engine, the PFR6B (Stock 3500) is the OEM-equivalent choice.

What's Included with 4853

Each 4853 order ships as a box of 4 plugs enough for a complete service on all five-cylinder Audi and Volvo applications listed in the fitment table. The BMW Alpina B7 4.4L V8 requires two boxes (8 plugs total) for a full engine set.

• 4 x NGK PFR7B (Stock No. 4853) Laser Platinum spark plugs
• 4 x Pre-installed crush washers (one per plug, gasket seat)
• Plugs are factory pre-gapped at 0.028 in (0.7mm) do not regap the platinum center electrode

Vehicle Fitment 4853 (PFR7B)

4853 fits the vehicles listed below. Confirm your exact year, engine displacement, and trim level before ordering. The Audi 200 Quattro fitment covers both the standard 20v and 20v Avant body styles. The 1997 Audi S6 fitment applies to the 2.2L L5 only; the V8 S6 uses a different plug. The 2007-2008 BMW Alpina B7 requires two boxes of NGK4853 for a full eight-plug service.

Full Specifications 4853 (PFR7B)

OEM and Aftermarket Cross-Reference

The 4853 (PFR7B) replaces or cross-references the following OEM and aftermarket part numbers. Always verify fitment by year, make, model, and engine before ordering cross-reference numbers confirm dimensional compatibility but do not substitute for a fitment check.

Warranty and Legal Information

Warranty: NGK 4853 is covered by NGK's 60-day limited warranty against defects in materials and workmanship. Service life is rated at 70,000 to 90,000 miles under normal operating conditions. The warranty period begins at the date of purchase and covers manufacturing defects only it does not cover damage from improper installation, gap adjustment on platinum/iridium electrodes, or use outside the confirmed fitment applications.

Magnuson-Moss Warranty Act: Installing 4853 in a vehicle it is confirmed to fit will not void your factory powertrain warranty. Under the federal Magnuson-Moss Warranty Act, a vehicle manufacturer cannot void your factory warranty solely because you installed an aftermarket part. They must demonstrate the aftermarket part directly caused the failure being claimed before denying coverage.

California Residents Proposition 65 Warning: This product can expose you to chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, visit www.p65warnings.ca.gov.

About NGK Spark Plugs

NGK Spark Plugs was founded in Nagoya, Japan in 1936 and has grown into the world's largest manufacturer of spark plugs and ceramic insulators. NGK supplies spark plugs as original equipment to virtually every major automaker on the planet, including Audi, BMW, Toyota, Honda, Subaru, Nissan, and Volvo. The Laser Platinum and Iridium IX series represent NGK's premium aftermarket lines, applying OEM-grade manufacturing processes including laser-welded electrode bonding and precision gap setting to plugs sold in the aftermarket. Every NGK plug is manufactured and tested to ISO 9001 standards at NGK's own facilities. The 4853 (PFR7B) is produced at NGK's Japanese manufacturing operations, which is reflected in the Japan country of origin designation.

Frequently Asked Questions 4853 (PFR7B)

Should I adjust the gap on before installing?
No. 4853 arrives factory pre-gapped at 0.028 in (0.7mm) and should be installed as-is. Do not attempt to re-gap platinum or iridium spark plugs. The fine-wire platinum center electrode is brittle compared to nickel bending or prying the ground electrode to change the gap risks cracking the platinum tip or fracturing the insulator. If your application requires a different gap, select the correct plug for that specification rather than attempting to adjust 4853.

How do I know is already pre-gapped?
NGK sets the gap at the factory on every Laser Platinum plug before it leaves the production line. The 0.028 in (0.7mm) gap on 4853 (PFR7B) is confirmed on the NGK product page and in NGK's published specifications. You can verify the gap with a feeler gauge without touching the electrode checking is fine, adjusting is not.

What does heat range 7 mean, and why is 4853 one step colder than OEM?
In NGK's numbering system, higher numbers indicate a colder heat range. A colder plug has a shorter insulator nose that conducts heat away from the firing tip faster, keeping electrode temperature lower under high-load conditions. 4853 at heat range 7 is one step colder than the PFR6B (stock 3500, heat range 6), which is the OEM plug for most stock applications in this plug family. The colder range of 4853 makes it the correct choice for chipped, tuned, or otherwise modified engines that produce more combustion heat than a stock unit. On a completely unmodified, stock engine, the PFR6B (Stock 3500) is the more appropriate selection.

How many plugs come in one box?
Each 4853 listing ships as a box of 4 plugs. This is a complete set for any five-cylinder engine in the fitment list (Audi 200 Quattro 2.2L L5, Audi S4 2.2L L5, Audi S6 2.2L L5, Volvo 850 2.3L L5). The 2007-2008 BMW Alpina B7 4.4L V8 uses eight plugs; you will need to order two boxes of 4853 for a full engine service on that application.

Why buy the 4-pack of 4853 instead of buying single plugs?
Spark plugs should always be replaced as a complete set never one or two at a time. Mixing plugs of different ages, wear levels, or even different heat ranges creates imbalanced cylinder-to-cylinder combustion timing that the ECU cannot fully compensate for. The 4853 four-pack is priced for a complete L5 engine service and eliminates the risk of mismatched ignition performance. Buying singles and assembling your own set costs more and introduces variables the 4-pack avoids entirely.

Will installing NGK void my factory warranty?
No. Under the federal Magnuson-Moss Warranty Act, installing an OEM-equivalent or OE-quality aftermarket spark plug does not void your factory powertrain warranty. A dealer or manufacturer must demonstrate that the aftermarket part directly caused the specific failure being claimed before they can deny warranty coverage. NGK is an OEM supplier to the same automakers whose vehicles are listed in the 4853 fitment table using NGK 4853 is not a modification.

Does require a Proposition 65 warning in California?
Yes. As a precautionary measure based on the materials present in spark plugs (including metals such as lead, nickel, and platinum compounds), 4853 carries a California Proposition 65 warning. California residents should be aware this product can expose you to chemicals known to the State of California to cause cancer and reproductive harm. See www.p65warnings.ca.gov for full information.

What is the recommended service interval?
NGK rates the PFR7B (4853) for a service life of 70,000 to 90,000 miles under normal operating conditions. That said, vehicles with higher output, forced induction, or aggressive tunes may benefit from inspection at 50,000-60,000 miles. Always follow your vehicle manufacturer's scheduled maintenance interval as the minimum baseline, and replace the full set of four plugs at each service.

What is the difference between Double Platinum and Iridium spark plugs?
Both designs use fine-wire precious-metal electrodes to maintain a stable gap and resist erosion over a long service life. Double platinum plugs like 4853 use a platinum center electrode and a platinum-tipped ground electrode excellent long-term wear resistance at a lower cost than iridium. Iridium plugs use a harder, higher-melting-point metal for the center electrode, which allows an even finer wire diameter and marginally lower required ignition voltage. For the Audi 200, S4, S6, Volvo 850, and BMW Alpina B7 applications listed, 4853 is the confirmed OEM-grade fitment. If an NGK iridium equivalent exists for your specific application and tune level, it would be listed separately under a different part number.

Is 4853 the same as PFR7B?
Yes. NGK uses two parallel numbering systems: an alphanumeric part number (PFR7B) and a numeric stock number (4853). 4853 is the SKU formed by combining the brand name with the stock number both refer to the identical plug. When cross-referencing or ordering from a distributor, either PFR7B or 4853 will identify the same product. The full name as listed by NGK is the Laser Platinum Spark Plug PFR7B, Stock Number 4853.