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Precision sealing for valve train compartment – The OEM D7500-1003201A Cylinder Head Cover Gasket is a Yuchai‑exclusive, multi‑layer steel (MLS) gasket designed to provide a perfect seal between the cylinder head cover and the cylinder head. Manufactured to exact original equipment specifications, this gasket prevents oil leaks, keeps contaminants out, and withstands extreme engine vibration and temperature cycles. For guaranteed compatibility and performance, always choose genuine Sinotruk Homan parts.
The D7500-1003201A cylinder head cover gasket is specifically engineered for Yuchai diesel engines used in SINOTRUK Homan trucks. It features a rubber‑coated steel construction with integrated stopper beads that provide controlled compression and compensate for surface irregularities. The gasket is pre‑formed to match the exact profile of the Yuchai cylinder head cover, ensuring a drop‑in fit without trimming or modification.
The D7500-1003201A is a multi‑layer steel (MLS) gasket composed of three perforated steel layers with a full‑face elastomer coating (FKM rubber). The middle layer features stopper beads that limit material compression, preventing over‑tightening and ensuring uniform clamp load across the entire sealing surface. This design is far superior to traditional cork or silicone gaskets, which can shrink, harden, or extrude under heat and oil exposure.
Yuchai engines (model families YC6A, YC6L, YC6M, YC6K) used in SINOTRUK Homan trucks demand a gasket that can withstand high blow‑by pressures and thermal expansion. The D7500-1003201A is tested to survive 1 million thermal cycles from ‑40°C to +150°C without losing sealing force. The integrated rubber beads also act as vibration dampers, reducing noise transfer from the valve train.
This gasket is fully compatible with both cast iron and aluminium cylinder head covers. Its thickness (1.5 mm) provides adequate gap filling for minor surface warpage (up to 0.2 mm) while the rubber coating conforms to local imperfections. Unlike aftermarket products, the OEM gasket has pre‑formed bolt holes with rubber eyelets that centre the gasket during assembly, eliminating misalignment.
3‑layer perforated steel core with FKM rubber coating, provides excellent recovery and resistance to oil and high temperatures.
Precision‑cut to match the Yuchai cylinder head cover contour. The D7500-1003201A ensures perfect alignment of bolt holes and oil drainback passages.
Integrated stopper beads prevent gasket crushing, maintain correct compression height, and eliminate the need for re‑torquing after initial assembly.
| OEM Number | D7500-1003201A |
| Product Name | Cylinder Head Cover Gasket (Yuchai Exclusive) |
| Brand | SINOTRUK Homan |
| Material | Multi-layer steel (3 layers) with full-face FKM rubber coating |
| Thickness (compressed) | 1.50 mm ± 0.05 mm |
| Gasket Type | Full perimeter, one‑piece, with integrated rubber bolt hole seals |
| Operating Temperature Range | -40°C to +160°C (continuous), peak 180°C |
| Maximum Pressure (crankcase blow‑by) | 200 kPa (2 bar) dynamic |
| Bolt Hole Quantity | 18 (Yuchai 6‑cylinder pattern) |
| Rubber Material | FKM (Viton) – oil and fuel resistant, hardness 70 Shore A |
| Steel Core Material | DC04 deep‑drawing steel, zinc‑nickel plated (corrosion protection) |
| Gasket Compression Limit (stop beads) | 1.45 mm (prevents over‑tightening) |
| Recommended Torque (cover bolts) | 10 Nm + 90° (dry) or 12 Nm (oiled) |
| Compatible Engine Models (Yuchai) | YC6A, YC6L, YC6M, YC6K, YC6MK, YC6T series (6‑cylinder) |
| Compatible Truck Models | SINOTRUK HOWO, A7, T7H, C7H with Yuchai engine option |
| Certification | IATF 16949, ISO 14001, Yuchai Engine approval |
The D7500-1003201A is manufactured using progressive die stamping to produce the three steel layers with precise perforations. The layers are then stacked, aligned, and clinched together. The FKM rubber is applied via a transfer moulding process that bonds the material to the steel core without air bubbles. Stopper beads are embossed onto the middle layer to act as compression limiters – this prevents the gasket from being crushed and ensures that the rubber maintains its sealing pressure for the life of the engine.
Each gasket is 100% visually inspected and then subjected to a 2‑bar air leak test on a fixture that simulates the cylinder head cover and cylinder head interface. Random samples undergo thermal cycle testing: 1,000 cycles from ‑40°C to +150°C while measuring load retention. The gasket retains over 95% of its original sealing force after 1,000 cycles, far exceeding the 80% industry standard.
The FKM rubber compound is specifically formulated for contact with hot engine oil, diesel fuel, and coolant condensation. It has excellent resistance to compression set (less than 15% after 100 hours at 150°C). The steel core is protected by a zinc‑nickel coating that withstands 500 hours of salt spray without red rust, making this gasket suitable for trucks operating in coastal or winter road salt conditions.
The FKM rubber used in the D7500-1003201A is resistant to engine oil (synthetic and mineral), diesel fuel, coolant (ethylene glycol), and acids formed during combustion blow‑by. Unlike nitrile (NBR) or silicone gaskets, FKM does not swell or soften in the presence of oil, maintaining consistent torque retention. The steel core is fully encapsulated by rubber, preventing any wicking of oil through the gasket layers.
The gasket’s design includes raised beads around the bolt holes that act as secondary seals, preventing oil from traveling up the bolt threads. This feature is critical for Yuchai engines where the valve cover bolts pass through the oil gallery area. The bead forms a tight seal even if the main gasket flange sees minor distortion.
The D7500-1003201A is a direct replacement for the original gasket on Yuchai diesel engines. It is symmetrical and cannot be installed upside down. The bolt holes have rubber grommets that center the gasket on the cover, ensuring perfect alignment of all holes. No additional sealant or adhesive is required; the gasket is designed to be installed dry.
Before installation, clean the cylinder head cover sealing flange and the cylinder head surface completely. Remove all old gasket material and oil residue. A thin film of oil on the bolt threads is allowed but not on the gasket itself. Torque the cover bolts in a cross‑pattern sequence to 10 Nm, then an additional 90° turn. Do not re‑torque after engine warm‑up – the stop beads maintain proper compression.
1) Disconnect the crankcase ventilation hose and any sensors attached to the cylinder head cover. 2) Remove the cover bolts in reverse order (outside‑in) to avoid warping the cover. 3) Lift the cover and discard the old gasket; never reuse a gasket once compressed.
4) Thoroughly clean the cover flange and cylinder head surface using a plastic scraper and brake cleaner. Ensure no old gasket bits remain, especially around bolt holes. 5) Inspect the cover for flatness (max 0.3 mm variation). If warped, replace the cover.
6) Lay the new D7500-1003201A gasket onto the cylinder head, aligning the bolt holes with the rubber grommets. 7) Install the cylinder head cover, making sure the gasket stays seated. 8) Insert bolts and tighten by hand, then torque to 10 Nm in a cross pattern, followed by a 90° angle turn.
9) Reconnect all hoses and sensors. 10) Start the engine and check for leaks at idle and at 2000 rpm. No leaks should be visible. Re‑inspect after a 30‑minute operating cycle; the gasket requires no re‑torquing.
The D7500-1003201A gasket is designed for the life of the engine. Signs of failure: oil weeping from the cylinder head cover seam, oil accumulation around the cover bolts, or visible cracking of the rubber coating. If a leak develops, first check bolt torque (should be 10‑12 Nm). If torque is correct but leakage continues, replace the gasket and inspect the cover for warpage or cracks.
Never apply silicone sealant to an MLS gasket – the rubber coating is sufficient and sealant can cause the gasket to extrude or block oil drain passages. If the engine has excessive blow‑by (worn piston rings), the crankcase pressure can blow past any gasket; address the root cause first.
The D7500-1003201A gasket is manufactured under IATF 16949 and ISO 14001 certified facilities. Each batch is 100% inspected for dimensional accuracy, rubber adhesion, and bead height. Random samples are subjected to thermal cycle testing (1,000 cycles of ‑40°C to +150°C), pressure pulsation test (200,000 cycles at 2 bar), and oil immersion test (1,000 hours in engine oil at 140°C).
The gasket meets Yuchai engineering standard YC/T 016 and SINOTRUK Homan standard Q/SQ 1055. A batch code and date stamp are embossed on the rubber surface for traceability. Counterfeit gaskets often have non‑uniform rubber coating, missing stopper beads, or incorrect steel layer thickness. Always purchase from authorized SINOTRUK Homan distributors and verify the QR code on the packaging.
A national haulage company in China operating 500 SINOTRUK T7H trucks equipped with Yuchai YC6L engines switched to genuine D7500-1003201A gaskets after experiencing oil leaks with aftermarket parts. After 2 years and over 700,000 km per truck, no gasket‑related oil leaks were reported. The service manager noted that the genuine gaskets maintained seal even after multiple thermal cycles.
Another fleet in Russia (Siberia) using YC6A engines in HOWO dump trucks reported that the D7500-1003201A gasket withstood extreme cold starts at ‑45°C without hardening or cracking. Previous cork‑composite gaskets had failed within one winter season. The FKM rubber remained flexible, and the steel core did not corrode despite road salt exposure.
Each genuine D7500-1003201A cylinder head cover gasket is supplied in a sealed plastic bag inside a SINOTRUK Homan branded carton. The bag includes a QR code label and a hologram sticker. The gasket itself has the SINOTRUK Homan logo and OEM number moulded into the rubber. Counterfeit gaskets often have a rough rubber surface, missing logos, or a single‑layer steel construction. The genuine gasket has a distinct three‑layer visible edge and the stopper beads are clearly embossed. Always scan the QR code before installation. Using a fake gasket can cause oil leaks, engine fires (oil on hot exhaust), and void the vehicle warranty.
Summary: The SINOTRUK Homan Cylinder Head Cover Gasket (OEM D7500-1003201A) provides a durable, leak‑proof seal for Yuchai diesel engines in heavy trucks. With multi‑layer steel construction, FKM rubber coating, and precision stop‑bead technology, this gasket eliminates oil seepage and ensures long engine life. Choose genuine for peace of mind – trust the part that Yuchai and SINOTRUK Homan engineers designed.
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