The part system on the HOWO MAX 4X2 MC13 engine relies on precision components to transport engine coolant at optimal temperatures. The outlet pipe of the thermostat is the primary pathway that directs hot coolant from the engine block to the radiator for heat dissipation. When you choose authentic Howo Parts, this Coolant water component kit guarantees OE fitment and leak free operation. Below are detailed descriptions of every component included with this Coolant water assembly.
The outlet pipe of thermostat is a cast aluminum or steel component that channels coolant from the thermostat housing to the radiator inlet. This Coolant water pipe is manufactured from high grade corrosion resistant aluminum alloy with a precision machined mating flange that accepts the thermostat gasket.
The pipe is engineered to withstand coolant pressures up to 2.5 bar and temperatures ranging from -40°C to 120°C. The internal bore is smooth and free of casting flash to ensure laminar flow, preventing turbulence that could reduce cooling efficiency. A properly functioning outlet pipe of thermostat is critical for maintaining the engine within its optimal operating range of 85°C to 95°C, preventing power loss, component wear, or serious damage due to overheating.
Two hexagon flange bolts with M8x130 dimensions and property class 10.9 are used to secure the thermostat outlet pipe flange to the cylinder head. These Coolant water bolts are manufactured from medium carbon alloy steel (40Cr/35CrMo) with a zinc nickel coating providing 240 hours of salt spray protection. The integral flange distributes clamp load evenly over the pipe flange, eliminating the need for separate washers.
The 130mm length allows these Coolant water bolts to pass through the pipe flange and any spacer bushings to reach the threaded bosses in the cylinder head.
The 10.9 property class provides a minimum tensile strength of 1,040 MPa and yield strength of 940 MPa. Apply a light film of engine oil to the threads before installation and torque these Coolant water bolts to 30 Nm (dry) or 22 Nm (lubricated) in a crossing pattern to ensure even gasket compression. The MAN183 quality mark indicates these Coolant water bolts meet SINOTRUK’s rigorous material and manufacturing standards, including a pre applied thread locking patch that activates during installation to prevent loosening under engine vibration.
One M8x70 flange bolt with class 10.9 and 70mm length is used to secure a support bracket or accessory mount on the thermostat housing. This Coolant water bolt has the same material composition, corrosion resistance, and strength rating as the M8x130 bolts but with a shorter length for applications where less thread engagement is required.
The 70mm length is ideal for mounting brackets that hold coolant hoses or wiring harnesses away from hot engine surfaces. Torque this Coolant water bolt to 30 Nm (dry) or 22 Nm (lubricated). When replacing the outlet pipe of thermostat, always install new Coolant water bolts, as the thread locking patch on previously torqued bolts will have been crushed and may not provide adequate vibration resistance.
Coolant water – genuine HOWO thermostat outlet pipe and hardware kit for MAX 4X2 MC13
The outlet pipe of thermostat is precision cast from corrosion resistant aluminum alloy with a smooth internal bore that minimises flow restriction. This Coolant water component maintains proper coolant circulation even under heavy engine loads, preventing localised overheating that could lead to head gasket failure.
All Coolant water bolts are property class 10.9 with a minimum tensile strength of 1,040 MPa and a zinc nickel coating for corrosion resistance. The MAN183 thread locking patch prevents loosening under engine vibration, ensuring the outlet pipe flange maintains its seal over thousands of thermal cycles.
The mating flange of the outlet pipe of thermostat is machined flat to within 0.05mm, providing a perfect sealing surface for the thermostat gasket. This Coolant water component eliminates the risk of coolant leaks caused by warped flanges, a common failure point on aged or aftermarket parts.
This Coolant water kit includes the outlet pipe and all three mounting bolts. When performing a thermostat replacement or cooling system repair, having the correct Coolant water hardware ensures proper clamp load and eliminates the risk of reusing stretched or corroded old bolts.
The part system on the HOWO MAX 4X2 MC13 engine uses a belt driven water pump to circulate a 50/50 mixture of ethylene glycol antifreeze and distilled water through the engine block, cylinder head, and radiator. When the engine is cold, the thermostat remains closed, forcing coolant to circulate through the bypass circuit and the heater core for rapid warm up.
Once the coolant reaches the thermostat’s opening temperature (typically 82°C to 88°C), the thermostat valve begins to open, allowing hot coolant to flow from the engine block into the outlet pipe of thermostat. This Coolant water pipe directs the hot coolant to the radiator inlet, where heat is dissipated to the atmosphere. The cooled coolant then returns to the water pump via the lower radiator hose.
The outlet pipe of thermostat must withstand continuous exposure to hot coolant at temperatures up to 120°C and pressures up to 2.5 bar. A cracked or corroded outlet pipe can cause sudden coolant loss, leading to rapid engine overheating and potential head gasket failure.
Before installing The part components, allow the engine to cool completely and drain the cooling system. Remove the old outlet pipe of thermostat and clean the mounting surface on the cylinder head and the thermostat housing. Inspect the mating surfaces for damage; if warped beyond 0.1mm, the cylinder head should be resurfaced.
Place a new thermostat gasket onto the mounting studs or bolt holes. Position the new outlet pipe of thermostat over the gasket, aligning the bolt holes with the threaded bosses. Insert the two M8x130 Coolant water bolts into the main mounting holes, and the one M8x70 bolt into the bracket mounting hole. Apply a small amount of thread sealant or engine oil to the bolt threads. Torque all Coolant water bolts to 30 Nm (dry) or 22 Nm (lubricated) in a crossing pattern, starting from the center and working outward.
Reconnect the radiator hose and fill the cooling system with the correct mixture of 50% ethylene glycol antifreeze and 50% distilled water. Start the engine and allow it to reach operating temperature while checking for leaks around The part pipe flange. If no leaks are present, the installation is complete.
If coolant leaks from the flange of the outlet pipe of thermostat, the most common cause is a failed gasket or loose Coolant water bolts. Retorque the M8x130 and M8x70 bolts to 30 Nm. If the leak persists, remove the pipe, inspect the gasket for damage, and replace it with a new one. Cracks in the outlet pipe of thermostat often appear near the flange or at stress risers around the hose connection. Inspect The part pipe carefully; any visible crack requires immediate replacement, as pressure cycling will cause the crack to propagate. If the engine overheats and the upper radiator hose remains cold,
the thermostat may be stuck closed or the outlet pipe of thermostat may be blocked by debris. Remove the pipe and inspect the internal bore. Coolant seepage from the bolt holes indicates that The part bolts are not sealing properly; replace the bolts with new ones, as the thread locking patch may have failed. A hissing sound from The part pipe area when the engine is hot suggests a pinhole leak; replace the pipe immediately. If the coolant level drops repeatedly with no visible external leak, perform a cooling system pressure test; a leak may be present at the outlet pipe of thermostat flange that only appears under pressure.
The outlet pipe of thermostat has no fixed replacement interval, but it should be inspected at every coolant change (typically every 80,000 km or every two years). Check The part pipe for signs of corrosion, pitting, or cracking. The flange bolts should be checked for tightness; retorque to 30 Nm if any are loose. The coolant mixture should be tested for proper freeze protection and pH balance (target pH of 8). Old coolant that has become acidic can corrode the outlet pipe of thermostat from the inside, leading to premature failure. Replace The part pipe if any internal corrosion is visible.
When replacing the thermostat or water pump, always install new Coolant water bolts, as used bolts may have lost their thread locking capability. After any cooling system service, perform a pressure test to 2.5 bar and verify that The part pipe and all connections hold pressure for at least 10 minutes.
This outlet pipe of thermostat and Coolant water hardware kit is specifically designed for the SINOTRUK MC13 engine used in HOWO MAX 4X2 tractors, SITRAK C7H, and HOWO T7H trucks. The part components fit all production years from 2018 onward and are compatible with the standard cooling system configuration.
The M8x130 Coolant water bolts are unique to the MC13 thermostat outlet pipe; MC11 engines use a shorter bolt length. This Coolant water kit is not compatible with older WD615 or D10 engine series, which use a different outlet pipe design and bolt pattern. Always verify your engine serial number before ordering this Coolant water kit.
Aftermarket outlet pipes of thermostat are often made from lower grade aluminum that corrodes rapidly, or from steel that rusts from the inside, contaminating The part system with rust particles that can block the radiator core. The flange faces on copy parts may not be machined flat, leading to gasket failure and coolant leaks within weeks of installation. Non genuine Coolant water bolts may be property class 8.8 instead of 10.9 and lack the MAN183 thread locking patch,
resulting in loosening under vibration and eventual joint separation. Genuine HOWO Coolant water components are manufactured to SINOTRUK’s exact specifications, using corrosion resistant aluminum alloy, precision machined flanges, and certified grade 10.9 fasteners. The small additional cost of a genuine outlet pipe of thermostat is insignificant compared to the cost of an engine rebuild caused by overheating from a sudden coolant loss.
We are a heavy-duty truck parts store. Please leave your contact information and inquiries. We will respond within 12 hours.
