Lower Water Pump Gasket – Fits Mercury/Tohatsu/Parsun 4-6 HP (Replaces PAT5-03000006, 27-16160004)
Lower Water Pump Gasket – Fits Mercury/Tohatsu/Parsun 4-6 HP (Replaces PAT5-03000006, 27-16160004) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Lower Water Pump Gasket – Fits Mercury/Tohatsu/Parsun 4-6 HP (Repla...
Product Details
This aftermarket Lower Water Pump Gasket provides a reliable seal for the outer water pump housing on a range of Mercury, Tohatsu, and Parsun outboards. It is designed to fit 4-6 HP 4-stroke models from 2005 to the present, as well as select 5 HP 2-stroke engines. The gasket ensures proper water pump function by preventing leaks between the housing and the lower unit gearcase.
This part directly replaces Mercury 16160/27-16160004, Parsun T5-03000006/PAT5-03000006, Tohatsu 369-65018-0/369650290, and Johnson/Evinrude 5040183. Refer to the Part Number Matrix for all cross-references.
- Creates a secure seal for the external water pump plate.
- Made from durable paper and fiber composite material.
- Installs in the lower gearcase to restore cooling system integrity.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 16160 |
| Mercury | 16160004 |
| Mercury | 27-16160 |
| Mercury | 27-16160004 |
| Parsun | T5-03000006 |
| Parsun | PAT5-03000006 |
| Johnson/Evinrude | 5040183 |
| Tohatsu | 369650290 |
| Tohatsu | 369650290M |
| Tohatsu | 369-65018-0 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Fits Mercury/Mariner 4-6 HP 4-stroke outboards (2005+) and certain 5 HP 2-stroke models.
Compatible with Tohatsu MFS4/5/6 series 4-stroke and M5B 2-stroke outboards.
Designed for Parsun F6A series 6 HP 4-stroke outboard models.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| Mercury | F4/F5/F6 | 4-6 | 4-Stroke | 2005–present | 16160, 16160004, 27-16160, 27-16160004 |
| Mercury | 5 HP | 5 | 2-Stroke | 16160, 16160004, 27-16160, 27-16160004 | |
| Tohatsu | MFS4/5/6 | 4-6 | 4-Stroke | 369650290, 369650290M, 369-65018-0 | |
| Tohatsu | M5B | 5 | 2-Stroke | 369650290, 369650290M | |
| Parsun | F6ABML, F6ABMS | 6 | 4-Stroke | T5-03000006, PAT5-03000006 | |
| Johnson/Evinrude | 5040183 |
Technical Specs
- Product Type
- Lower Water Pump Gasket
- Installation
- External Plate Gasket
- Material
- Paper/Fiber Composite
- Dimensions
- 10.0" (L) x 7.0" (W) x 0.3" (H)
- Weight
- Approx. 0.12 lbs (0.05 kg)
- Application
- Outer water pump housing gasket
- Part Position
- Lower gearcase
What’s in the Box
- 1 x Lower Water Pump Gasket (PAT5-03000006)
Installation Notes
- Disconnect the battery and spark plug wire for safety.
- Place a drain pan under the lower unit and remove the gearcase oil drain screw to empty the oil.
- Remove the bolts securing the lower unit (gearcase) to the engine's upper section.
- Carefully separate the lower unit from the driveshaft housing.
- Unbolt and remove the water pump housing to access the old gasket.
- Remove the old gasket and thoroughly clean both mounting surfaces, ensuring they are free of debris and old material.
- Position the new gasket correctly on the cleaned surface.
- Reinstall the water pump housing and tighten the bolts to the manufacturer's specified torque.
- Reassemble the lower unit to the engine, refilling the gearcase oil with the correct type and amount.
Troubleshooting & FAQ
How do I know if this gasket fits my engine?
Confirm your model and year in the compatibility table. The most reliable method is to match the OEM part number from your engine's service manual with the numbers in our Part Number Matrix.
What are the signs of a failing lower water pump gasket?
Common symptoms include engine overheating, a weak water stream from the "telltale" outlet, or visible water leakage from the seam between the water pump housing and the lower unit.
Can I reuse my old gasket?
No. Water pump gaskets are single-use components. They compress and deform upon installation to create a seal and should always be replaced whenever the water pump is serviced.
How often should this gasket be replaced?
It is best practice to replace the water pump gasket and impeller as part of regular annual service, or every 100 hours of operation, especially if used in saltwater.
What material is this gasket made from?
This gasket is produced from a high-quality paper and fiber composite, which is standard for marine water pump applications, providing a reliable seal in wet conditions.
Is this part different from the original OEM gasket?
Our aftermarket gasket is designed to match the form, fit, and function of the original OEM part. It serves as a direct replacement using comparable materials and manufacturing standards.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
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