Thermostat – Fits Mercury Mercruiser, Cummins Mercruiser 2.0L Diesel Engines 115-170 HP (Replaces 879150054)
Thermostat – Fits Mercury Mercruiser, Cummins Mercruiser 2.0L Diesel Engines 115-170 HP (Replaces 879150054) is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Thermostat – Fits Mercury Mercruiser, Cummins Mercruiser 2.0L Diese...
Product Details
This is a replacement Thermostat for Mercury Mercruiser 2.0L Diesel Engines from 115 to 170 HP. It is designed to fit 2.0L inline-4 diesel engines, including Mercury/Mercruiser models and Cummins/Mercruiser QSD 2.0L engines in both EI and ES configurations.
This assembly serves as a direct replacement for Mercury/Mercruiser OEM part number 879150054.
- Designed for direct OEM replacement installation.
- For use in diesel fuel marine environments.
- Engineered for 2.0L inline-4 diesel engines.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury/Mercruiser | 879150054 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Compatible with a range of Mercury Mercruiser 2.0L diesel sterndrive engines.
Also fits various Cummins Mercruiser (CMD) QSD 2.0L diesel engines.
| Brand | Model | Rated HP | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Mercury Mercruiser | 2.0L EI 115 | 115 | 4-Stroke | 879150054 | Diesel |
| Mercury Mercruiser | 2.0L EI 130 | 130 | 4-Stroke | 879150054 | Diesel |
| Mercury Mercruiser | 2.0L EI 150 | 150 | 4-Stroke | 879150054 | Diesel |
| Mercury Mercruiser | 2.0L EI 170 | 170 | 4-Stroke | 879150054 | Diesel |
| Mercury Mercruiser | 2.0L ES 130 | 130 | 4-Stroke | 879150054 | Diesel |
| Mercury Mercruiser | 2.0L ES 150 | 150 | 4-Stroke | 879150054 | Diesel |
| Mercury Mercruiser | 2.0L ES 170 | 170 | 4-Stroke | 879150054 | Diesel |
| Cummins Mercruiser | CMD QSD 2.0 EI 115 | 115 | 4-Stroke | 879150054 | Diesel |
| Cummins Mercruiser | CMD QSD 2.0 EI 130 | 130 | 4-Stroke | 879150054 | Diesel |
| Cummins Mercruiser | CMD QSD 2.0 EI 150 | 150 | 4-Stroke | 879150054 | Diesel |
| Cummins Mercruiser | CMD QSD 2.0 ES 130 | 130 | 4-Stroke | 879150054 | Diesel |
| Cummins Mercruiser | CMD QSD 2.0 ES 150 | 150 | 4-Stroke | 879150054 | Diesel |
| Cummins Mercruiser | CMD QSD 2.0 ES 170 | 170 | 4-Stroke | 879150054 | Diesel |
Technical Specs
- Product Type
- Thermostat Assembly
- Installation
- Direct OEM replacement
- Fuel Type
- Diesel
- Housing Material
- Metal
- Weight
- 0.20 lb (0.09 kg)
- Other Technical Attributes
- For 2.0L inline-4 diesel engines
What’s in the Box
- 1 x Thermostat (879150054)
Installation Notes
- Ensure the engine is completely cool before starting. Disconnect the boat's battery.
- Locate the thermostat housing on the engine. Place a container underneath to catch any spilled coolant.
- Drain the engine coolant to a level below the thermostat housing.
- Carefully remove the bolts securing the housing cover. Gently tap the cover if it is stuck, but do not pry it.
- Note the orientation of the old thermostat before removing it. The spring assembly typically faces the engine.
- Thoroughly clean the mating surfaces of the housing and its cover, removing all old gasket material.
- Install the new thermostat in the same orientation as the old one.
- Place a new gasket on the housing and reinstall the cover, tightening bolts to the manufacturer's specified torque in a cross-pattern.
- Refill the cooling system with the appropriate coolant.
- Reconnect the battery, start the engine, and let it reach operating temperature, checking carefully for any leaks around the housing.
Troubleshooting & FAQ
How do I know if my thermostat is failing?
Common signs of a faulty thermostat include engine overheating, the engine not reaching normal operating temperature, erratic temperature gauge readings, or coolant leaks from the thermostat housing area.
What is the correct way to install this thermostat?
The spring-loaded side of the thermostat assembly should always face the engine block. Always consult your engine's service manual for model-specific diagrams and procedures.
Is a new gasket required for installation?
Yes, replacing the gasket is critical to prevent leaks. This package includes the thermostat only; the housing gasket must be sourced separately. Ensure you use the correct gasket for your specific engine model.
When should a marine thermostat be replaced?
Thermostats should be inspected during routine cooling system service or replaced as a preventative measure every few hundred hours or every few years, especially if operating in saltwater. Replace it immediately if you notice any signs of failure.
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.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
