Forklift Cylinder head cover

Forklift Cylinder Head Cover: Valve Covers & Rocker Covers for Xinchai 490B 4D27G31 Changchai Yuchai Nissan

The cylinder head cover — also called valve cover or rocker cover — is the stamped steel or cast aluminum cover bolted to the top of the cylinder head that seals the entire valvetrain assembly (valves, rocker arms, rocker shaft, and camshaft) from external dirt, debris, and moisture contamination. It serves a dual function: containing the pressurized oil spray from rocker arm lubrication (at 30-60 psi engine oil pressure) and providing the oil fill cap mounting point and crankcase breather/PCV connection. A warped, cracked, or bent cylinder head cover causes oil to leak onto the hot exhaust manifold directly below — a serious fire hazard on diesel engines where exhaust manifold surface temperatures reach 300-400°C. A leaking cover gasket, stripped bolt threads, or deformed cover flange are the most common failure points. The cover gasket is a one-time-use component that takes a permanent compression set after the first heat cycle — reusing an old gasket is the number one cause of repeat leaks after valve cover service.

Kingstream supplies replacement cylinder head covers for Xinchai 490B/495/498 (the most common Chinese forklift engine), XinChai 4D27G31 (HELI CPCD30), Changchai 4G33V16 (agricultural and forklift diesel), Yuchai YC4FA series, Nissan K21/K25 LPG engines, and universal cast aluminum alloy valve covers. Every cover is inspected for gasket flange flatness, bolt hole thread condition, and overall straightness before shipment.

Types:
• Xinchai 490B (A490B-11001) — 100% original Xinchai OEM valve cover for 490B/495/498 diesel engines in HELI/Hangcha/Baoli 2-3.5T forklifts. 1kg, 1-year warranty, Chongqing
• XinChai 4D27G31 (4D27G31-11100-3) — OEM valve cover for 4D27G31 diesel engine in HELI CPCD30 and Baoli 3T forklifts. High-temperature resistant steel, 2kg, 3-month warranty
• Changchai 4G33V16 (4G33V16-010008) — OEM valve cover for Changchai 4G33V16 diesel engine in tractors, forklifts, and farm trucks. 1kg, 6-month warranty, Jiangsu
• Yuchai YC4FA — Universal cylinder head cover for Yuchai YC4FA diesel engines. Fits multiple Yuchai-powered forklift and industrial applications
• Cast Aluminum Alloy — Universal cast aluminum valve cover. Superior heat dissipation compared to stamped steel. Fits multiple engine platforms
• Nissan K21/K25 (91H20-00310) — Full cylinder head assembly for Nissan K21/K25 LPG engines in F01 series forklifts (1975-1996). Complete assembly with valves. 9kg, 18-month warranty

When to Replace Cylinder Head Covers:
• Oil leak from the top of the engine running down the side of the cylinder head, especially after recent valve adjustment or gasket replacement → Cover gasket is leaking. Replace gasket and inspect cover for warpage
• Repeated valve cover gasket leaks after multiple gasket replacements → The cover flange is warped or deformed from previous overtightening. The gasket cannot seal a warped surface. Replace the cover
• Stripped bolt hole threads in the cover — bolts will not achieve proper torque → The cover bolt bosses are damaged. Temporary Helicoil repair is possible on some covers; replace cover for permanent fix
• Cracked or punctured valve cover from impact damage (dropped tool, forklift collision) → Oil will leak through the crack. Welding stamped steel covers is unreliable due to warping. Replace
• Cover removed for any upper engine repair (head gasket, valve adjustment, rocker replacement) and found to have internal corrosion or pitting → Corroded interior surfaces shed particles that contaminate the oil. Replace cover

OEM Cross-Reference:

Don’t see your engine? Send your engine model and cover type →

Compatible: Xinchai 490B/495/498, XinChai 4D27G31, Changchai 4G33V16, Yuchai YC4FA, Nissan K21/K25. Browse our engine parts catalog.