Sierra Distributor Cap 18-5395 with Gasket, Replaces Mercury Marine 805759T1, for GM V-8 Thunderbolt IV & V HEI Ignitions

The Sierra 18-5395 Distributor Cap is a direct-fit ignition component for GM V-8 marine engines equipped with Thunderbolt IV and Thunderbolt V HEI ignition systems. It ships complete with the gasket needed for installation, so there is no need to source a separate seal. The cap is built with a moisture-proof, molded insulator body and a high-quality conductive center carrier that maintains consistent conductor integrity for reliable spark delivery.

This is part of Sierra's MAGFORCE-compatible ignition lineup, engineered to be "electronics friendly" so it protects onboard electronic devices and electronic engine controls from RFI and EMI interference while still delivering maximum voltage to the ignition system. The cap features a black machined metal housing with a twist-on closure for a secure, exact-fit installation that seats correctly against the distributor body every time.

The 18-5395 is used across several MerCruiser stern-drive applications with 540 and 572 cubic inch V-8 engines, including the 500 Bulldog, 575, and 800 SC models. Every Sierra part is built to meet or exceed the performance of the original equipment part it replaces, and it is backed by Sierra's standard limited warranty.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-5395
• Product Type: Distributor Cap
• Included Components: Distributor Cap, Gasket
• Material: Metal
• Color: Black
• Exterior Finish: Machined
• Closure Type: Twist-On
• Item Dimensions: 0.39 x 0.39 x 0.39 inches
• Weight: 0.82 pounds
• Fitment: GM V-8 Engines With Thunderbolt IV & V HEI Ignitions
• OEM Cross Reference: Mercury Marine 805759T1
• UPC: 030999319135

Fitment

• MerCruiser 500 Bulldog, 540 cid V-8, 1990-2001
• MerCruiser 575, 540 cid V-8, 1986-1992
• MerCruiser 800 SC, 572 cid V-8, 1993-1998

Replaces (OEM)

• Mercury Marine 805759T1

Frequently Asked Questions

What engines does the Sierra 18-5395 distributor cap fit? The 18-5395 is designed for GM V-8 engines equipped with Thunderbolt IV and Thunderbolt V HEI ignition systems, and it is used on MerCruiser 500 Bulldog, 575, and 800 SC applications with 540 and 572 cubic inch V-8 engines.

Does the 18-5395 distributor cap include the gasket? Yes, the Sierra 18-5395 comes with the gasket included, so no separate gasket purchase is needed for installation.

What is the OEM equivalent for part number 18-5395? Sierra 18-5395 cross-references to Mercury Marine part number 805759T1.

What material is the 18-5395 distributor cap made from? It is made from black machined metal with a moisture-proof, molded insulator construction and a conductive center carrier for consistent conductor integrity.

How does the cap attach to the distributor? The 18-5395 uses a twist-on closure design for a secure, exact-fit installation on GM V-8 distributors with Thunderbolt IV/V HEI ignitions.

What are the dimensions of the 18-5395 distributor cap? The cap measures 0.39 x 0.39 x 0.39 inches.

How much does the Sierra 18-5395 weigh? The distributor cap weighs 0.82 pounds.

Is the Sierra 18-5395 an OEM or aftermarket part? It is an aftermarket Sierra replacement part engineered to meet or exceed the performance of the original equipment distributor cap it replaces, including the Mercury Marine 805759T1.

Will the 18-5395 protect onboard electronics from interference? Yes, this cap is built to be electronics friendly, shielding electronic devices and electronic engine controls from RFI and EMI while still delivering maximum voltage.

What MerCruiser models use the 18-5395 distributor cap? It is used on the MerCruiser 500 Bulldog (1990-2001), 575 (1986-1992), and 800 SC (1993-1998), all 540 or 572 cubic inch V-8 configurations.

Is a warranty included with the 18-5395 distributor cap? Yes, the Sierra 18-5395 is covered under Sierra's standard limited warranty.