Thermostat Gasket – Fits Mercury MerCruiser V6/V8 (Replaces 27-48818Q01)

$1.99 $3.00

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Product Details

This high-quality Thermostat Gasket – Fits Mercury MerCruiser V6/V8 (Replaces 27-48818Q01) ensures a reliable seal between the thermostat and its housing. It is designed for Mercury MerCruiser V6 and V8 GM engines with standard cooling systems from 1982 and older, as well as high-performance models up to 1996.

It serves as a direct replacement for multiple part numbers, including Sierra 18-2844, GLM 31510, Mallory 9-60010, Mercury 27-48818Q01, and several OMC equivalents.

Engineered for gasoline marine engines with standard cooling systems.
Installs directly between the thermostat and the thermostat housing.
Package contains one thermostat gasket for a complete replacement.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number
Sierra	18-2844
GLM	31510
Mallory	9-60010
Mercury	27-48818
Mercury	27-488181
Mercury	27-48818Q01
OMC	0508562
OMC	0508566
OMC	0508619
OMC	0508717

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This gasket is designed for MerCruiser V6 and V8 GM engines with standard cooling systems, covering models from 1982 and older, plus high-performance variants up to 1996.

The listed OMC part numbers are for cross-reference purposes. Verify fitment against your specific engine model before ordering.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
MerCruiser	V8 engines	Various	4-Stroke	1982 and older	27-48818Q01	Standard cooling system
MerCruiser	V6 engines	Various	4-Stroke	1982 and older	27-48818Q01	Standard cooling system
MerCruiser	High Performance	Various	4-Stroke	Up to 1996	27-48818Q01	Models with standard cooling
OMC	Various	Various	4-Stroke		0508562/0508566/0508619/0508717	Cross-reference only

Technical Specs

Product Type: Thermostat Gasket
Installation: Between thermostat and housing
Fuel Type: Gasoline
Housing Material: Paper/Composite
Dimensions: 6.0" L x 7.5" W x 0.13" H
Weight: Approximately 0.01 kg (0.02 lbs)
Warranty: Manufacturer standard warranty
Other Technical Attributes: Designed for standard cooling systems

What’s in the Box

1 x Thermostat Gasket (27-48818Q01)

Installation Notes

Disconnect the battery and ensure the engine has completely cooled before starting work.
Drain the engine coolant to a level below the thermostat housing to prevent spills.
Carefully loosen and remove the bolts that secure the thermostat housing.
Remove the old thermostat and gasket. Thoroughly clean both mating surfaces, ensuring no old gasket material or residue remains.
Position the new thermostat correctly within the engine block or housing.
Place the new gasket into position, ensuring it aligns with the bolt holes and sealing surfaces.
Reinstall the thermostat housing and tighten the bolts to the manufacturer's recommended torque in a star pattern.
Refill the cooling system with the appropriate coolant, check for leaks, and run the engine to confirm proper operation.

Troubleshooting & FAQ

How do I know if this gasket will fit my engine?

This gasket fits MerCruiser V6/V8 GM engines (1982 & older) and high-performance models (up to 1996) with standard cooling. Always match your engine's OEM part number (27-48818Q01) to the references in our Part Number Matrix.

What are the signs of a failing thermostat gasket?

Common signs include coolant leaks around the thermostat housing, engine overheating, or fluctuating engine temperature readings. A visual inspection may reveal cracking or deterioration of the old gasket.

Can I reuse my old gasket?

No. Thermostat gaskets are single-use components designed to crush and create a seal. Always use a new gasket when replacing the thermostat or servicing the housing to prevent leaks.

Do I need sealant with this gasket?

This paper/composite gasket is typically designed to be installed dry. Applying sealants can sometimes cause the gasket to slip or fail prematurely. Always follow your engine's service manual recommendations.

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

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