The Honda 12357-Z5T-020 Breather Tube is a genuine OEM replacement designed for GX240, GX270, GX340, and GX390 horizontal shaft engines, as well as WT30 and WT40 water pumps. As a direct Honda OEM part, it is manufactured to the same specifications as the original component it replaces, ensuring a correct fit without modification. Confirm your engine or pump serial number against the fitment table before ordering, as Honda supersedes parts at serial breaks and more than one configuration may exist across this model range.
Key Features
- Genuine Honda OEM — sourced directly from Honda, this breather tube matches the original part in geometry and material, ensuring the crankcase ventilation path is restored exactly as designed.
- Broad Fitment — covers GX240, GX270, GX340, and GX390 horizontal shaft engines, plus WT30 and WT40 water pumps; verify your serial number against the fitment table to confirm the correct variant for your unit.
- Crankcase Pressure Control — a correctly functioning breather tube prevents pressure buildup in the crankcase; a cracked, collapsed, or missing tube can allow oil misting, excessive blowby, or oil leaks at gasket faces.
The breather tube is part of the engine's crankcase ventilation system. Its job is to route blowby gases — combustion gases that slip past the piston rings into the crankcase — back into the intake or air cleaner, preventing pressure from building up inside the engine. When the tube cracks, collapses, or becomes clogged, crankcase pressure rises, which can force oil past seals and gaskets, contaminate the air filter, or cause oil consumption issues. Replacing a worn or damaged tube with a genuine Honda part restores proper ventilation and keeps the engine running cleanly across its full operating range.
Part Details
| Part Number | 12357-Z5T-020 |
|---|---|
| Brand | Honda |
| Part Type | Genuine OEM |
| Description | Breather Tube |
Compatibility & Fitment
| Name | Models | Serial Range |
|---|---|---|
| Horizontal Shaft Engine | GX240, GX270, GX340, GX390 | All |
| Water Pump | WT30, WT40 | All |
Verify Before You Order
Fitment is machine-number and revision-specific; always confirm your model and serial number against the fitment list.
Why Buy From DHS Equipment
Every part is verified against the manufacturer's part number before it ships, so what you order is what arrives. We carry parts from leading OEM brands and our own DHS Quality Parts line of professional aftermarket components. Need help finding the right part? Our team is available to confirm compatibility whenever you need it. Orders are processed fast to keep your jobs on track. We don't just sell parts. We keep you jobsite ready.
Questions? Contact our team at [email protected] or 866-611-9369 — DHS Equipment is here to help you maintain peak performance.
