The open-type crankcase ventilation system is essential for managing blow‑by gases from the MC13 engine. This open-type crankcase ventilation system routes crankcase vapors through an oil separator, then vents them to the atmosphere while returning captured oil to the sump. When you choose authentic Howo Parts, this open-type crankcase ventilation kit guarantees reliable pressure control and oil separation. Below are detailed descriptions of every component included with this open-type crankcase ventilation assembly kit.
The oil-gas separator air outlet pipe assembly is the main hose that carries cleaned crankcase vapors from the oil‑gas separator to the atmosphere. This open-type crankcase ventilation pipe is made from oil‑resistant synthetic rubber reinforced with textile braid, designed to withstand continuous exposure to hot blow‑by gases without softening or collapsing.
The pipe is pre‑formed to the correct shape for the MC13 engine layout and includes molded end fittings that accept the elastic steel belt clamps. The outlet pipe assembly ensures that blow‑by gases are safely vented away from the engine compartment, preventing oil mist accumulation on components.
The connecting hose is a short rubber tube that links the oil‑gas separator outlet to the air outlet pipe assembly. This open-type crankcase ventilation hose is made from FKM rubber for superior heat and oil resistance, capable of withstanding temperatures up to 180°C. The hose has a smooth inner bore to minimize flow restriction and an outer fabric covering for abrasion resistance. It is secured at both ends using the supplied elastic steel belt clamps, ensuring a leak‑free connection. This connecting hose is a critical part of the open-type crankcase ventilation system, as any crack or leak here would allow unfiltered blow‑by gases to escape into the engine bay.
Two elastic steel belt clamps with dimensions 29mm width and 12mm tightening range are used to secure the hoses of the open-type crankcase ventilation system. These clamps are made from spring steel with a self‑tightening design that maintains constant tension on the hose as it expands and contracts with temperature changes. Unlike worm‑drive clamps, these elastic clamps do not cut into the rubber and provide a uniform sealing force around the entire circumference. They are used to attach both the connecting hose and the air outlet pipe assembly to the oil‑gas separator ports. The open-type crankcase ventilation system relies on these clamps to prevent blow‑by gas leaks that could cause a hissing noise or oil smell in the cab.
The transition joint is a steel fitting that connects the oil return pipe from the oil‑gas separator to the engine block return port. This open-type crankcase ventilation component is made from zinc‑plated steel with a machined sealing seat for the toric seal.
It has a barbed end that accepts the rubber oil return pipe and a threaded end with a composite sealing washer that bolts to the engine block. The transition joint ensures that captured oil is directed back into the sump without leakage. Without this joint, the open-type crankcase ventilation system would allow oil to drain onto the ground rather than returning it to the engine.
The toric seal is an O‑ring with dimensions 17mm inner diameter and 2mm cross section, made from FPM rubber. This open-type crankcase ventilation seal is installed in the transition joint to seal the connection between the oil return pipe and the engine block. The FPM material provides excellent resistance to hot engine oil and blow‑by gas chemicals, maintaining its elasticity even after thousands of thermal cycles. A properly seated toric seal prevents oil leaks that could create a mess on the engine block or, worse, drip onto hot exhaust surfaces creating a fire hazard.
One M6x30 flange bolt with class 10.9 strength and 30mm length is used to secure the oil‑gas separator to its mounting bracket. This open-type crankcase ventilation bolt features an integral flange that distributes clamping load evenly, eliminating the need for a separate washer. The extra length accommodates the thickness of the separator mounting foot and any spacer bushings. Torque this bolt to 12 Nm to ensure the separator remains rigidly attached without cracking its plastic housing.
One M6x16 flange bolt with class 10.9 strength and 16mm length is used to secure the transition joint or a bracket in the open-type crankcase ventilation system. This shorter bolt is used where thread depth is limited, such as in thin bosses on the engine block. Torque this bolt to 12 Nm as well. The 10.9 grade ensures the bolt can withstand the vibration of the diesel engine without loosening.
The oil return pipe is a rubber hose that carries captured oil from the oil‑gas separator down to the transition joint. This open-type crankcase ventilation hose is made from nitrile rubber (NBR) with a smooth bore to prevent oil accumulation. The hose is pre‑cut to the correct length for the MC13 engine and is secured at both ends using clamps (not included).
Proper routing of this oil return pipe is essential; it must slope continuously downward to allow gravity drainage of the collected oil back to the sump. A kink or sag in this open-type crankcase ventilation hose would prevent oil from draining, causing the separator to fill and eventually push oil into the air outlet pipe, creating a smoky exhaust.
Two M14x25 flange bolts with class 10.9 strength and 25mm length are used to secure the oil‑gas separator mounting bracket to the engine block. These large‑diameter bolts provide a very strong attachment for the relatively heavy separator assembly. The flange head distributes the clamping load, and the 10.9 grade ensures the bolts will not stretch under the vibration of the engine. Torque these open-type crankcase ventilation bolts to 50 Nm. Never reuse these bolts if they have been removed, as they are torque‑to‑yield fasteners.
The oil return piping is a second section of oil return hose, typically used on engine variants with a longer distance between the separator and the engine block return port.
This open-type crankcase ventilation pipe is made from the same NBR rubber as the primary return pipe and is secured with the same type of clamps. In some MC13 engine configurations, the oil return path requires two separate hoses connected by a steel union; this piping provides that extension. Always inspect this piping for kinks or swelling during routine service.
A 250ml bottle of Loctite 242 thread locker is included for securing the bolts in the open-type crankcase ventilation system. This medium‑strength, removable thread locker prevents loosening due to vibration while still allowing disassembly with hand tools. A small drop of Loctite 242 should be applied to the threads of the M6 and M14 bolts before installation, especially on the bolts that secure the separator to its bracket. Using thread locker ensures that the open-type crankcase ventilation components remain tightly fastened even after thousands of operating hours.
open-type crankcase ventilation – genuine HOWO blow‑by gas management kit for MAX 4X2 MC13
This open-type crankcase ventilation kit includes the outlet pipe, return hoses, transition joint, toric seal, all clamps, and the required fasteners. No extra components are needed to install or repair the MC13 engine’s crankcase ventilation system.
All hoses in this open-type crankcase ventilation kit are made from NBR or FKM rubber specifically formulated for continuous exposure to hot oil and blow‑by gases. They resist swelling, cracking, and hardening, ensuring a long service life.
Unlike conventional worm‑drive clamps, the open-type crankcase ventilation system uses elastic clamps that maintain constant tension through thermal cycles. These clamps do not cut into the hoses and provide a uniform, leak‑free seal.
A 250ml bottle of Loctite 242 is supplied to ensure that the open-type crankcase ventilation bolts remain tight under engine vibration. Using thread locker on the M6 and M14 bolts prevents loosening and blow‑by gas leaks.
During engine operation, high combustion pressure forces a small amount of gas past the piston rings and into the crankcase. This blow‑by gas contains unburned fuel, water vapor, and fine oil mist. If allowed to accumulate, the pressure would push oil out of seals and gaskets. The open-type crankcase ventilation system relieves this pressure by ducting the blow‑by gases to an oil‑gas separator. Inside the separator, the heavy oil droplets coalesce on a filter element and drain to the bottom of the separator housing.
The cleaned gases then exit through the air outlet pipe assembly and connecting hose, venting to the atmosphere via the air outlet pipe. The captured oil flows by gravity through the oil return pipe, transition joint, and into the engine block return port, where it drains back to the oil pan. The toric seal and transition joint ensure that no oil leaks at the engine block connection. Without a functional open-type crankcase ventilation system, crankcase pressure would build, leading to oil leaks from the rear main seal, valve cover gaskets, and turbocharger seals.
Before installation, disconnect the battery and allow the engine to cool. Remove the old open-type crankcase ventilation hoses and separator. Clean any oil residue from the engine block return port and the mounting bracket. Apply a drop of Loctite 242 to the threads of the two M14x25 bolts and secure the oil‑gas separator bracket to the engine block, torquing to 50 Nm. Mount the separator to its bracket using the M6x30 bolt (torque 12 Nm,
with thread locker). Install the transition joint into the engine block return port using the toric seal and the M6x16 bolt (torque 12 Nm). Connect the oil return pipe of oil‑gas separator between the separator outlet and the transition joint, securing each end with an elastic steel belt clamp. Attach the connecting hose to the separator outlet and the air outlet pipe assembly, again using the elastic clamps. Route the air outlet pipe assembly so that it points downward and away from the exhaust manifold. Start the engine and check for leaks or hissing sounds.
If the engine produces a hissing sound that increases with load, a crack or loose connection in the open-type crankcase ventilation hoses is likely. Inspect the connecting hose and air outlet pipe for splits, and tighten the elastic clamps. If oil residue appears on the engine block near the transition joint, the toric seal may be damaged or the bolt may be loose.
Replace the toric seal and retorque. If the oil return pipe is kinked or clogged, oil will accumulate in the separator and be pushed out through the air outlet pipe, causing a smoky exhaust and oil consumption. Inspect the return hose for kinks and blow through it to check for blockage. If the engine has excessive blow‑by due to worn piston rings, the open-type crankcase ventilation system cannot compensate; a compression test will confirm internal wear. A faulty oil‑gas separator (not included in this hose kit) can also cause oil carryover; if oil is present in the air outlet pipe, the separator element may require replacement.
Inspect the open-type crankcase ventilation hoses every 50,000 km or during each oil change. Squeeze the hoses to check for hardening or cracking; if they feel brittle or show visible cracks, replace them with genuine components. The elastic clamps do not require adjustment, but inspect them for rust or loss of tension; replace any clamp that no longer holds the hose firmly.
The oil return pipe should be checked for kinking and for signs of oil leakage at the transition joint. The toric seal can be replaced as a precaution when the oil return pipe is removed. If the engine oil becomes contaminated with fuel or coolant, the open-type crankcase ventilation hoses may degrade prematurely; address the source of contamination first. Loctite 242 should be applied each time the bolts are removed, as the original thread locker will have cured.
This open-type crankcase ventilation hose kit is compatible with the SINOTRUK MC13 engine found in HOWO MAX 4X2 tractors, SITRAK C7H, and HOWO T7H trucks. The kit fits all production years from 2018 onward and is designed for the open‑type system that vents to the atmosphere.
This open-type crankcase ventilation kit is not compatible with closed‑type systems that route blow‑by gases back into the intake air (closed crankcase ventilation). It is also not compatible with the MC11 or WD615 engine platforms, which use different hose lengths and connectors. Always verify your engine serial number and the type of crankcase ventilation system installed before ordering.
Aftermarket open-type crankcase ventilation hoses are often made from non‑reinforced rubber that softens and collapses under engine heat, restricting blow‑by flow and increasing crankcase pressure. Generic clamps may not be the correct diameter or may use worm‑drive mechanisms that cut into the hose. Non‑genuine toric seals may be made from NBR instead of FPM rubber,
which hardens and leaks. The bolts in copy kits may not be genuine grade 10.9 fasteners and may stretch or break. Genuine HOWO open-type crankcase ventilation components are manufactured to SINOTRUK’s exact specifications, using oil‑resistant FKM/NBR rubber, spring steel clamps, FPM seals, and certified grade 10.9 bolts. The small additional cost of a genuine open-type crankcase ventilation kit is insignificant compared to the cost of engine damage caused by excessive crankcase pressure or oil leaks.
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