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Gaskets and Seals› Engine Gaskets and Seals

Cometic

MLS Head Gasket, 3.840" Bore, .040" Thickness, RHS

$112.63 $101.37 Save $11.26

SKU: C5721-040

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Overview

The Cometic C5721-040 is a Multi-Layer Steel (MLS) head gasket designed for Buick 3800 Series II/III V6 engines. It features a bore size of 3.840 inches and a compressed thickness of .040 inches. This gasket is specifically intended for the right-hand side (RHS) head.
Show original supplier description
The Cometic C5721-040 is a Multi-Layer Steel (MLS) head gasket engineered for Buick 3800 Series II/III V6 engines with a 3.840-inch bore. This specific gasket is for the right-hand side (RHS) cylinder head and has a compressed thickness of .040 inches. MLS gaskets are known for their superior sealing capabilities under extreme conditions, offering greater tolerance to temperature and pressure fluctuations, making them ideal for modified engines. Cometic recommends installing MLS gaskets dry, as they are coated with a .001-inch thick Viton rubber sealant that should not be supplemented with additional sealants. The Cometic C5721-040 head gasket is compatible with a range of vehicles including Buick models like the LeSabre, Park Avenue, Regal, and Riviera (1996-2003). It also fits Chevrolet Camaro (1996-2002), Impala (2000-2003), Lumina (1998-1999), and Monte Carlo (1998-2003). For Oldsmobile, it fits the 88 (1996-1999), 98 (1996), Intrigue (1998-1999), LSS (1996-1999), and Regency (1997-1998). Pontiac models include Bonneville (1996-2003) and Firebird (1996-2002), as well as Grand Prix (1997-2003). It is also compatible with Holden Caprice VS (1996) and various 3.8L V6 Ecotec engines, including the L67 Supercharged variant.
Vehicle Symptoms
  • Coolant loss without visible leaks
  • Overheating under load or highway driving
  • White smoke from exhaust on startup
  • Engine misfire at idle or acceleration
  • Oil in coolant or milky oil on dipstick
Diagnostic Codes
  • P0300 – Random or multiple cylinder misfire Det
  • P0301 – Cylinder 1 misfire Det
  • P0302 – Cylinder 2 misfire Det
  • P0303 – Cylinder 3 misfire Det
  • P0304 – Cylinder 4 misfire Det
  • P0305 – Cylinder 5 misfire Det
  • P0306 – Cylinder 6 misfire Det
  • P0128 – Coolant Thermostat Temp Below Regulating Temp
Relevant Conversations
  • Buick 3800 series 2 head gasket failure symptoms
  • Cometic C5721-040 MLS head gasket review
  • How to replace head gasket on 3800 V6
  • White smoke from exhaust Buick 3800 fix
  • P0300 random misfire Buick 3800 head gasket
  • MLS vs OEM head gasket for 3800
  • Overheating Buick 3800 after head gasket replacement
  • Cometic head gasket thickness .040 vs .036
  • Head gasket job cost Buick 3800
  • Best head gasket for boosted 3800

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

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Specifications

BrandCometic
Part NumberC5721-040
CategoryGaskets and Seals
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