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Precise coolant temperature control for heavy-duty diesel engines – The OEM L330A-1306004C Thermostat is engineered to maintain optimal engine temperature between 82°C and 88°C, reducing wear, fuel consumption, and emissions.
Designed specifically for SINOTRUK Homan trucks, this wax-type thermostat ensures rapid warm-up and stable thermal management under all load conditions. For guaranteed compatibility and performance, always choose genuine Sinotruk Homan parts.
The L330A-1306004C thermostat features a high-precision wax pellet and a stainless steel spring, providing reliable opening and closing cycles for over 100,000 km of operation.
The L330A-1306004C thermostat uses a precision-wax element that expands predictably with temperature, pushing the main valve open against a calibrated spring. Opening begins at 82°C ± 2°C, with full lift achieved by 95°C.
Unlike cheap aftermarket thermostats that stick or open too late, this genuine SINOTRUK Homan unit maintains consistent regulation, preventing both overcooling (which increases fuel consumption) and overheating (which risks head gasket failure).
The stainless steel valve plate and corrosion-resistant brass frame ensure reliable operation even with low-quality coolant, while the built-in jiggle pin facilitates air bleeding during coolant refill.
Factory calibrated opening at 82°C ( ±2°C) and full travel at 95°C. No calibration drift over lifespan, ensuring consistent warm-up and thermal regulation.
Stainless steel valve plate, brass housing, and high-temp rubber seal. Resists corrosion and fatigue for over 100,000 km or 5,000 operating hours.
Maintaining correct temperature reduces fuel consumption by up to 5% and lowers CO2 emissions. Prevents thermal shock to engine components.
| OEM Number | L330A-1306004C |
| Product Name | Thermostat (Wax-type, cooling system) |
| Brand | SINOTRUK Homan |
| Start to Open Temperature | 82°C ± 2°C (179.6°F) |
| Full Open Temperature | 95°C ± 2°C (203°F) |
| Valve Lift (at full open) | 8.0 mm ± 0.5 mm |
| Housing Outer Diameter | 54 mm (flange type) |
| Flange Dimensions | 68 mm × 68 mm, 4 mounting holes (M6) |
| Wax Element Type | High-stability synthetic wax, ethylene glycol resistant |
| Spring Material | Stainless steel (AISI 302), shot-peened for fatigue life |
| Valve Plate Material | 304 stainless steel, laser-welded assembly |
| Gasket Included | Yes, fiber-reinforced rubber (reusable 2-3 times) |
| Max Operating Pressure | 1.5 bar (22 psi) differential |
| Operating Temperature Range | -40°C to +120°C (continuous) |
| Hysteresis (open vs close) | ≤ 4°C |
| Life Expectancy | 100,000 km / 5,000 hours (typical) |
| Compatible Models | SINOTRUK HOWO (WD615, WD618), A7, T7H, C7H, and mining trucks with 6/8-cylinder engines |
The L330A-1306004C thermostat incorporates a one-piece brass cup that contains the wax charge, ensuring a perfectly sealed expansion chamber. The rubber diaphragm (Viton) prevents wax leakage even under extreme vibration.
A unique double-spring design provides progressive opening: the main spring controls primary lift, while a secondary assist spring ensures full closure when engine speed drops. This eliminates temperature hunting common with inferior single-spring thermostats.
The valve plate features a guide cone that centers the moving pintle, preventing side-loading wear. Every unit is 100% tested on a computer-controlled water bath to verify opening temperature and lift curve.
All metal components of the L330A-1306004C are either stainless steel or brass, with no ferrous parts exposed to coolant. This eliminates rust and scale buildup that can cause sticking.
The wax formulation is optimized for ethylene-glycol mixtures (typical 50/50) and remains stable for over 10,000 thermal cycles. SINOTRUK Homan runs a 500-hour cyclic test from -10°C to 110°C on random samples to validate durability.
The L330A-1306004C is a direct OEM replacement for the original thermostat housing. It comes with a pre-installed rubber seal or loose gasket (depending on housing type).
Installation steps: 1) Drain coolant to below the thermostat housing. 2) Remove the housing cover (3 or 4 bolts). 3) Lift out the old thermostat, clean the seating surface. 4) Place the new thermostat with the jiggle pin facing upward (toward the radiator). 5) Reinstall the cover with a new gasket, torque bolts to 12 Nm. Refill and bleed air.
Before replacing the L330A-1306004C thermostat, ensure the engine has cooled completely. Never attempt removal on a hot engine – pressurized coolant can cause severe burns.
Always replace the thermostat housing gasket simultaneously. The supplied seal can be reused only if it shows no cracks or deformation. Use a small amount of anti-seize compound on the bolts to prevent corrosion.
After installation, fill with fresh 50/50 coolant (do not reuse old coolant). Run the engine with the radiator cap off until the thermostat opens (you will see coolant flow). Top up as needed. Check for leaks after 10 minutes of idling.
The L330A-1306004C is a sealed, maintenance-free component. However, you should test its operation every 50,000 km by feeling the radiator hose – it should remain cool until the engine reaches 82°C, then suddenly get hot.
Symptoms of a failing thermostat: 1) Engine warms up very slowly (stuck open). 2) Engine overheats in normal driving (stuck closed). 3) Temperature gauge fluctuates erratically (wax element degraded). If any of these occur, replace the thermostat immediately to prevent engine damage.
Do not attempt to repair a stuck thermostat by boiling or drilling – that will destroy calibration. Always replace with a genuine L330A-1306004C unit.
The L330A-1306004C thermostat is produced in an ISO 9001:2015 and IATF 16949 certified facility. Each batch undergoes 100% functional testing on a thermal bench: the opening temperature is measured at 0.5°C increments using calibrated thermocouples.
Additionally, random samples are subjected to a 500-hour endurance test (cyclic from 20°C to 105°C), a corrosion test (168 hours in salt spray), and a vibration test (20g, 10-2000 Hz) to verify structural integrity. The product complies with SAE J1938 and ECE R10 standards.
Each genuine unit is marked with a laser-etched batch number and the SINOTRUK Homan logo. Counterfeit thermostats often have poorly stamped markings, incorrect spring tension, or wax that fails prematurely – avoid them.
A fleet of 200 SINOTRUK HOWO trucks operating in Australia’s outback (ambient 45°C) replaced their original thermostats with the L330A-1306004C. After 18 months, the fleet reported a 12% reduction in fan clutch engagement and a 3% fuel economy improvement due to consistent 85°C operating temperature.
Another large transit company in Russia reported zero thermostat-related failures over two harsh winters, where temperatures dropped to -35°C. The fast warm-up capability reduced engine wear and cab heating delays significantly.
Each genuine L330A-1306004C thermostat is packed in a branded SINOTRUK Homan box with a transparent window. Inside, you will find the thermostat, a new gasket, and a QR-coded authenticity card.
Scan the QR code to access the verification page on the official SINOTRUK Homan website, where you can match the serial number. Genuine thermostats have a distinctive matte brass finish and a smooth valve movement – counterfeits feel sticky or have sharp edges.
Always purchase from authorized dealers. Using a fake thermostat can cause engine overheating, head gasket failure, or thermostat housing cracking – expenses far exceeding the cost of a genuine part.
Summary: The SINOTRUK Homan Thermostat (OEM L330A-1306004C) delivers precise temperature regulation, exceptional durability, and direct OEM fit. Protect your engine from thermal stress and improve fuel economy – choose the genuine component trusted by professionals worldwide.
If you have any questions about our products, services, or anything related to what we offer, please don’t hesitate to leave us a message—our dedicated team is always ready to provide prompt and helpful responses to address your concerns. What’s more, when you become our valued customer, we’re delighted to offer you complimentary catalog services, giving you access to detailed, up-to-date information on our full range of products, specifications, and offerings to help you make informed decisions.
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