Recommended Nylon Grades for Automotive Fan Shrouds

Working Conditions of Fan Shrouds

Fan shrouds operate in engine bays under continuous thermal radiation of 110–140°C, temperature cycling ranging from -40°C to 130°C, constant vibration from cooling fans, and long-term exposure to coolant vapor, sediment and engine oil. Key material requirements include low warpage, thermal stability, creep resistance, low-temperature impact resistance and stable dimensional performance to guarantee fan dynamic balance. Two mainstream material systems are widely adopted: mineral/glass fiber hybrid reinforced PA6 (cost-effective grade) and heat-stabilized PA66-GF30 (universal standard grade).

1. Universal Standard Grade for Mass-Produced ICE & NEVs: Heat-Stabilized Hydrolysis-Resistant PA66-GF30 (Industry Benchmark)

Selection Rationale

Reinforced with 30% glass fiber, this grade delivers continuous heat resistance up to 140°C, low molding shrinkage and outstanding high-temperature creep resistance. Large thin-wall integrated shrouds maintain consistent shape without warpage, ensuring uniform clearance between fans and radiators to eliminate abnormal vibration noise. Its hydrolysis-resistant formulation withstands ethylene glycol condensate and prevents brittle cracking after long-term thermal aging in engine compartments.

Imported Representative Grades

1. BASF Ultramid A3WG6 Global OEM benchmark for fan shrouds; low viscosity & high flowability for thin-wall filling of large one-piece shrouds, low anisotropic shrinkage and excellent fan dynamic balance; standard black compound for original factory shrouds.
2. LANXESS Durethan AKV30 H1.0 Long-term thermal stabilization with superior resistance to hydrolysis under 135°C coolant exposure, ideal for high heat-load hybrid vehicles.
3. DOMO TECHNYL A218 V30 Balanced rigidity and toughness, minimal glass fiber blooming, suitable for integrated shrouds with integrated buckles and mounting brackets.
4. DuPont Zytel 70G30HS1L Upgraded hydrolysis-resistant variant, factory-matched for coastal high-humidity and hybrid vehicles.

Domestic Alternative Grades

PA A3WG6 ,PA 70G30HS1L,PA A218 V30 (low odor & low VOC grade specially developed for new energy vehicles)

2. Cost-Effective Grade for Entry-Level Vehicles: Mineral & Glass Fiber Hybrid Reinforced PA6 (Low-Warpage Special Grade)

Selection Rationale

Combined mineral and glass fiber fillers drastically reduce warpage caused by single glass fiber reinforcement, with superior melt flowability and lower cost compared to PA66. Designed for entry-level naturally aspirated vehicles with low engine heat load. Limitation: maximum continuous service temperature of 120°C, not applicable to turbocharged or high-heat hybrid engine bays.

Representative Grade (BASF Core Product)

Ultramid B3WGM35 R03 (PA6 with 15% GF + 25% Mineral Filler) 40% total hybrid filler delivers ultra-low shrinkage and minimal sink marks, preventing deformation of large fan shrouds and shortening injection molding cycle time; widely used in entry-level ICE vehicle fan housings.

Lightweight Single Glass Fiber PA6 Grades

BASF B3EG10 (PA6-GF10), B3EG20 (PA6-GF20) Low glass fiber content delivers enhanced toughness and light weight, only applicable to small auxiliary air ducts and split mini shrouds; inadequate rigidity for large main shrouds, prone to resonance deformation under vibration.

3. Upgraded Grades for High-Load Hybrid & High-Displacement Turbo Vehicles: PA66-GF33 / Glass Bead Modified PA66

1. High-Rigidity Creep-Resistant PA66-GF33 (DOMO A218 V33, DuPont 70G33HS1L) 33% glass fiber filler delivers higher flexural modulus, maintaining stable geometry under long-term vibration at 150°C high temperature; specified for heavy-duty shrouds of 2.0T+ high-boost turbo engines and high-power hybrid vehicles.
2. Glass Bead Reinforced PA66 A216 S30  Partial short glass fibers replaced by solid glass beads to achieve nearly isotropic shrinkage with extreme low warpage; premium grade for high-end new energy vehicles requiring strict fan coaxiality tolerance.

4. Special Modified Nylon Grades for Fan Shroud Segmented Applications

1. Low-Odor PA66-GF30 Developed for new energy vehicles with engine bays adjacent to passenger compartments; low VOC emission to meet automotive interior environmental regulations.
2. Toughened PA6/PA66-GF30 (HSL Toughening System) Specially formulated for frigid northern regions; maintains integrity under -40°C drop-weight impact, resisting cracking during winter disassembly and stone impact (PA73G30HSL).
3. MoS₂ Lubricated PA6 (PA L6Y10) Not used for main shroud bodies; exclusively for internal fan shaft bushings and sliding buckles to deliver self-lubricating silent operation.

Material Selection Comparison Table for Fan Shrouds

Material Grade	Continuous Heat Resistance	Warpage Control	Cost	Applicable Vehicle Types	Disadvantages
Mineral/Glass Hybrid PA6-GF15 (B3WGM35)	≤120°C	Optimal	Lowest	Entry-level naturally aspirated compact cars, small split shrouds	Prone to creep deformation in high-temperature turbo engine bays, insufficient heat resistance
Heat-Stabilized PA66-GF30 (A3WG6)	140°C	Excellent	Medium	Most ICE passenger vehicles, standard new energy vehicles (universal industry standard)	Inferior ultra-thin-wall low-warpage performance vs mineral hybrid PA6
High-Rigidity Hydrolysis-Resistant PA66-GF33	160°C	Outstanding	Medium-High	2.0T+ turbo vehicles, high heat-load hybrid shrouds	Poor melt flowability, risk of short shots in ultra-thin wall sections, obvious glass fiber blooming
Glass Bead Reinforced PA66-G30 A216 S30	150°C	Top-Tier	High	Premium new energy vehicles, fan assemblies requiring precise coaxiality	High raw material cost

Quick Material Selection Guide

1. Standard 1.2T–1.8T ICE passenger vehicles & general new energy vehicles → Heat-stabilized PA66-GF30 (PA66 A3WG6)
2. Low-cost entry-level compact cars, naturally aspirated engines, cost priority → Mineral/glass hybrid filled PA6 B3WGM35
3. 2.0T+ high-displacement turbo vehicles, high-heat hybrid engine bays, long-term high-temperature vibration → Hydrolysis-resistant PA66-GF33
4. Vehicles operating in frigid northern regions, requiring superior low-temperature stone impact resistance → Toughened HSL grade PA66-GF30
5. Silent internal sliding bushing small parts only → PA6 L6Y10 unfilled lubricated PA6