AC Delco 41-993 Iridium Spark Plug | Replaces 41-932, NGK PTR4G-15, Crusader RP030011, Volvo Penta 3861326 | GM V8 Marine Engines | MerCruiser, Crusader & Volvo Penta Applications | Sold Individually

AC Delco 41-993 Iridium Spark Plug — Replaces AC Delco 41-932, NGK PTR4G-15, Crusader RP030011 & Volvo Penta 3861326 | GM V8 Marine Engines | MerCruiser, Crusader & Volvo Penta Applications | Sold Individually

AC Delco 41-993 is an iridium spark plug used in GM V8 marine engines across MerCruiser, Crusader, and Volvo Penta stern drive and inboard applications. Directly replaces the AC Delco 41-932 (predecessor part number), NGK PTR4G-15, Crusader RP030011, and Volvo Penta 3861326. Sold individually — order the quantity needed for your engine.

Part Specifications

• Part Number: AC Delco 41-993
• SKU: ACD-41-993
• Plug Type: Iridium
• Replaces (AC Delco): 41-932 (direct predecessor part number)
• Replaces (NGK): PTR4G-15
• Replaces (Crusader): RP030011 (see also: Crusader RP030011 Spark Plug Kit MP6.0L Platinum 6-pack)
• Replaces (Volvo Penta): 3861326 (see also: Volvo Penta 3861326 Spark Plug 4-Pack Platinum)
• OEM Status: OEM replacement for GM V8 marine engine applications across multiple marine engine manufacturers
• Sold As: Individually (single plug) — order quantity to match your engine’s cylinder count

Cross-Reference & Replacement Guide

The 41-993 consolidates several part numbers across marine engine manufacturers. If your engine currently uses any of the following plugs, the AC Delco 41-993 is the replacement:

• AC Delco 41-932: The 41-993 is the current AC Delco part number that supersedes the 41-932. If your service manual or existing plugs show 41-932, order 41-993 as the current replacement.
• NGK PTR4G-15: The 41-993 is the AC Delco equivalent of the NGK PTR4G-15 platinum/iridium plug used in the same GM V8 marine engine applications. Note: the NGK 7862 (PZTR5A-15) is a related NGK platinum plug also available in this catalog — verify your engine’s specific NGK part number before ordering either plug.
• Crusader RP030011: The 41-993 is the individual plug equivalent of the Crusader RP030011 Spark Plug Kit, which is a 6-plug kit for the Crusader 6.0L MP engine. If you are replacing one plug individually rather than the full kit, order the 41-993 by quantity.
• Volvo Penta 3861326: The 41-993 is the individual plug equivalent of the Volvo Penta 3861326 4-Pack. If your Volvo Penta engine uses the 3861326 plug, order the 41-993 by the cylinder count of your engine.

Compatible Marine Engine Applications

The 41-993 is used across a range of GM V8-based marine engines. Verify against your engine service manual or existing plug part number before ordering:

• Crusader 6.0L MP MPI marine engines: The 41-993 is the individual plug for the Crusader 6.0L MP, for which Crusader lists RP030011 as the 6-plug kit
• Volvo Penta 5.7L and 6.0L GXi / OSi marine engines: The 41-993 is used in Volvo Penta GM V8-based stern drive engines where Volvo Penta lists 3861326 as the plug part number
• MerCruiser GM V8 applications: Some MerCruiser GM V8 engine configurations use the 41-993 or the predecessor 41-932 — verify against your MerCruiser service manual for your specific engine model and year
• Other GM V8 marine applications: Any marine engine manufacturer using a GM V8 block that cross-references to the NGK PTR4G-15 or AC Delco 41-932/41-993 may use this plug — confirm against your engine documentation
• Note — not the same as the 41-110: The AC Delco 41-110 is a different iridium plug for GM LS-series marine engines (MerCruiser Gen V 4.5L/6.2L, Volvo Penta V8-300/350/380). The 41-993 and 41-110 are not interchangeable — confirm which plug your engine requires before ordering.

Application Notes

• Sold individually — order the quantity matching your engine’s cylinder count (e.g., 8 plugs for a V8 engine)
• Verify the correct gap specification for your engine in the service manual before installation — iridium plugs are typically pre-gapped and should not be re-gapped with standard gapping tools, as the fine-wire tip can be damaged
• Thread the plug in by hand for the first several turns to avoid cross-threading aluminum heads; torque to the specification in your engine service manual
• Apply anti-seize only if specified by your engine manufacturer — many OEM iridium plug installations do not require anti-seize, and over-application on aluminum heads can cause torque errors
• Change at the interval specified in your engine service manual; iridium plugs in marine service should not have intervals extended beyond the manufacturer’s recommendation

Additional Information

• Vendor: AC Delco
• SKU: ACD-41-993
• Part Number: 41-993
• Replaces: AC Delco 41-932 | NGK PTR4G-15 | Crusader RP030011 | Volvo Penta 3861326
• Product Type: Boat & Engine Maintenance / Spark Plugs
• Plug Type: Iridium
• Sold As: Individually (single plug)
• Country of Origin: USA
• HS Code: 8511.10 (spark plugs — verify for your import classification)

Frequently Asked Questions

Q: Is the 41-993 a direct replacement for the AC Delco 41-932?
A: Yes — the 41-993 is the current AC Delco part number that supersedes the 41-932. If your engine service manual or existing plugs reference the 41-932, order the 41-993 as the current replacement.

Q: How many plugs come in this listing?
A: This listing is for one (1) individual spark plug. Order the quantity to match your engine’s cylinder count — for example, 6 plugs for a Crusader 6.0L MP (6-cylinder) or 8 plugs for a V8 engine. The Crusader RP030011 kit and Volvo Penta 3861326 4-pack are available if you prefer a pre-counted set.

Q: Is the 41-993 the same plug as the AC Delco 41-110?
A: No — the 41-110 is for GM LS-series marine engines (MerCruiser Gen V 4.5L/6.2L, Volvo Penta V8-300/350/380 LS-based). The 41-993 is for different GM V8 applications including Crusader 6.0L MP and Volvo Penta 5.7L/6.0L GXi/OSi. They are not interchangeable — confirm which plug your engine requires.

Q: Does the 41-993 replace the Volvo Penta 3861326?
A: Yes — the 41-993 is the individual AC Delco plug equivalent for applications where Volvo Penta lists 3861326. The Volvo Penta 3861326 4-pack is also available if you need a pre-counted set for a 4-cylinder application.

Q: Can I re-gap an iridium spark plug?
A: Iridium plugs are pre-gapped and should not be re-gapped with standard coin-type or wire gapping tools, as the fine-wire iridium electrode tip can be damaged by contact with the tool. Verify the gap is correct for your engine specification visually; if it requires adjustment, use only a gap tool that does not make contact with the center electrode tip.