The CMT-EZ4 is a zinc engine anode (E4 style) with 1/2″ UNC thread, designed to protect internal engine cooling systems from galvanic corrosion. Installed in the engine block or heat exchanger, it acts as a sacrificial elementcorroding first to protect critical internal components.

This larger E4-style anode provides increased surface area and longer service life compared to smaller pencil anodes, making it ideal for engines requiring higher corrosion protection capacity.

Key Features

E4 style engine anode
1/2″ UNC threaded pencil zinc
Marine-grade high-purity zinc construction
Increased length for extended protection life
Designed for saltwater applications
Available as anode-only or complete plug assembly

Application / Compatibility

Designed for:

Inboard marine engines
Heat exchanger systems
Raw water-cooled engines

Common on:

Volvo Penta
MerCruiser
Yanmar
Crusader

Used in systems requiring larger capacity anodes for extended protection

Serial Number / Fitment Notice

Always confirm:

Thread size (1/2″ UNC)
Anode length and diameter
Whether your setup requires anode-only or full plug assembly

Correct sizing is critical for proper protection and fit.

When This Part Needs Replacement

Anode is 50% or more consumed
Heavy scaling or deterioration
Reduced cooling efficiency
Routine seasonal maintenance

Installation Notes

Thread into existing brass plug or housing
Ensure clean threads and proper seating
Do not overtighten
Inspect regularly in saltwater use
Replace before full depletion to maintain protection

Alternate / Superseded Part Numbers

Camp Company: CMT-EZ4
Martyr: CMEZ4
Common reference: E-4Z / CME 4 Z
Also available as complete assembly (with brass plug)

Parts Desk Insight

E4 anodes are used where engines need more protection volumethey last longer but are just as critical to monitor. If customers are burning through these quickly, it can indicate high electrolysis or bonding issues, not just normal wear.