Keep your Duramax diesel engine running at the proper operating temperature with the DTPD Dual Engine Coolant Thermostat Set, designed for 2001–2016 Chevrolet and GMC vehicles equipped with the 6.6L Duramax turbo diesel engine.
The 6.6L Duramax utilizes a dual-thermostat cooling system to regulate coolant circulation and maintain optimal engine operating temperatures.
Over time, factory thermostats can become worn, stick open, or fail in the closed position, potentially causing engine overheating, slow warm-up times, inconsistent coolant temperatures, and reduced heater performance.
This DTPD Set of 2 Thermostats provides a convenient and affordable solution for replacing both thermostats during cooling system maintenance or repairs.
Whether you're servicing your daily driver, work truck, or heavy-duty towing vehicle, DTPD provides dependable replacement components at competitive prices.
Complete Dual Thermostat Set: Includes 2 engine coolant thermostats.
Direct Replacement Design: Designed to replace the original factory-style thermostats.
Proper Temperature Regulation: Helps maintain consistent engine operating temperatures.
Improved Cooling System Performance: Restores proper coolant flow regulation when replacing faulty thermostats.
Durable Construction: Designed for demanding diesel engine operating conditions.
Convenient Maintenance Solution: Replace both thermostats together rather than purchasing them separately.
Affordable OEM Alternative: Factory-style replacement without the expensive dealership pricing.
CHEVROLET SILVERADO — 6.6L DURAMAX DIESEL
| Years | Make | Model | Engine |
|---|---|---|---|
| 2001–2004 | Chevrolet | Silverado 2500HD / 3500 | 6.6L LB7 |
| 2004.5–2005 | Chevrolet | Silverado 2500HD / 3500 | 6.6L LLY |
| 2006–2007 | Chevrolet | Silverado 2500HD / 3500 | 6.6L LBZ |
| 2007.5–2010 | Chevrolet | Silverado 2500HD / 3500HD | 6.6L LMM |
| 2011–2016 | Chevrolet | Silverado 2500HD / 3500HD | 6.6L LML |
GMC SIERRA — 6.6L DURAMAX DIESEL
| Years | Make | Model | Engine |
|---|---|---|---|
| 2001–2004 | GMC | Sierra 2500HD / 3500 | 6.6L LB7 |
| 2004.5–2005 | GMC | Sierra 2500HD / 3500 | 6.6L LLY |
| 2006–2007 | GMC | Sierra 2500HD / 3500 | 6.6L LBZ |
| 2007.5–2010 | GMC | Sierra 2500HD / 3500HD | 6.6L LMM |
| 2011–2016 | GMC | Sierra 2500HD / 3500HD | 6.6L LML |
CHEVROLET GMC MEDIUM-DUTY TRUCKS
| Years | Make | Model | Engine |
|---|---|---|---|
| 2003–2009 | Chevrolet | Kodiak C4500 / C5500 | 6.6L Duramax |
| 2003–2009 | GMC | TopKick C4500 / C5500 | 6.6L Duramax |
Medium-duty applications require verification of the original thermostat configuration before purchase.
Compatible with the following 6.6L Duramax diesel engine generations:
LB7: 2001–2004
LLY: 2004.5–2005
LBZ: 2006–2007
LMM: 2007.5–2010
LML: 2011–2016
Important: Not intended for 2017+ L5P Duramax engines.
Quantity: 2 Engine Coolant Thermostats
1 Primary Engine Coolant Thermostat
1 Secondary Engine Coolant Thermostat
Both thermostats are designed to work together in the factory dual-thermostat cooling system.
Faulty thermostats may cause:
Engine running colder than normal
Excessively long engine warm-up times
Engine overheating
Inconsistent coolant temperature readings
Reduced cabin heater performance
Check engine light related to coolant temperature regulation
Diagnostic trouble code P0128
Replacing both thermostats together can help restore proper cooling system operation and prevent repeated repairs.
Professional installation is recommended.
For best results:
Allow the engine to cool completely before beginning repairs.
Drain the necessary amount of coolant.
Remove the thermostat housing according to the manufacturer's service procedures.
Remove both original thermostats.
Install the replacement thermostats in their correct positions.
Inspect and replace seals or gaskets as needed.
Refill the cooling system with manufacturer-approved coolant.
Properly bleed air from the cooling system and inspect for leaks.
IMPORTANT: Always follow factory service procedures and verify proper thermostat orientation during installation.
At Diesel Truck Parts Direct (DTPD), we specialize in replacement parts for Duramax, Powerstroke, and Cummins diesel engines.
We are committed to offering quality replacement components at competitive prices, backed by fast and reliable shipping.
DTPD BENEFITS:
Quality aftermarket diesel replacement parts
Competitive pricing
Fast order processing
Free shipping
Knowledgeable diesel parts support
Products stocked in our warehouse
DTPD — DIESEL TRUCK PARTS DIRECT
Quality Diesel Parts. Great Prices. Fast Shipping. No B.S.
Please verify your vehicle's year, make, model, engine code, and original thermostat configuration before purchasing.
This listing includes two engine coolant thermostats only. Thermostat housings, coolant, and additional installation components are not included unless specifically pictured or stated.
If you are unsure about compatibility, contact us before ordering.