VW TL 52682 PA66 Finished Parts Carrying Glass Fiber Reinforced Coolant

The standard “VW TL 52682 PA66 Glass fiber reinforced coolant-carrying finished parts - Material requirements”, developed by the Volkswagen automotive company, describes the material requirements for glass fiber reinforced PA66 used in coolant-carrying parts. Volkswagen standard VW 50133 applies to components made from PA66-GF30 that do not come into contact with coolant.

General requirements have been defined as follows:

• According to VW 01155 standard, initial supply and modifications must be approved.
• According to VW 50026 standard, granular material must be supplied for thermoplastic parts.
• Environmental requirements must be met according to the VW 91100 standard.
• Material conformity must be ensured according to the VW 91101 standard.

Tests to determine mechanical properties must be performed on standard samples produced by injection molding. Milling is not permitted for sample production for tests to determine coolant resistance.

Finished parts must be free from processing irregularities such as voids, cracks, and cold joints, which negatively affect strength, service life, and desired appearance. This applies to both the surface and interior of the part.

Indentation marks in the area of ​​ribs, reinforcement elements and fittings are acceptable only if they do not negatively affect assembly or functionality. The parts must allow for flawless assembly.

There should be no functional risk or risk of injury to assembly workers due to burrs, roughness, or loose particle debris.

The glass fibers should be distributed evenly in the material to such an extent that the glass fiber content of samples taken from three different points of a finished part does not differ by more than 1,0 percent.

During injection molding or a related process (e.g., water injection technology), the use of homogenously recycled material from the initial processing stage is permitted up to 30 percent by weight. Parts must be verified to have the expected maximum percentage of recycled material.

According to this standard, a distinction is made between dry and conditioned conditioning conditions:

• The dried samples were dried until their weight remained constant and stored in a continuously dry environment prior to testing.
• Conditioned samples are obtained by incubating dry samples in a waterproof bag filled with water at 70 degrees Celsius until the specified equilibrium state is reached. Alternatively, samples can be conditioned according to the DIN EN ISO 1110 standard.

In short, the VW TL 52682 standard ensures that components such as coolant pipes, expansion tanks, thermostat housings, and radiator end tanks maintain their structural integrity, leak-proofness, and long-term durability under the demanding conditions of the engine cooling system.

The main purpose of this standard is as follows:

• To guarantee resistance to hydrolysis (protection against coolant degradation)
• To ensure mechanical strength and dimensional stability at high temperatures.
• Defining test protocols for production approval and quality control.

According to this standard, the material must have the following basic properties:

• Glass fiber content: 30% plus/minus 2% by weight. Test method according to DIN EN ISO 1172 standard.
• Density: 1,36 plus/minus 0,02 g/cm³³The test method is according to the DIN EN ISO 1183-1 standard.
• Moisture content (as received): 1,0-3,0% by weight. Test method: drying at 100 degrees.
• Melting point: At least 255 degrees.
• Ball indentation hardness: Minimum 195 N/mm²²

Additional requirements include:

• Bending strength and modulus
• Impact resistance (notched)
• Heat aging behavior
• Low temperature performance
• Resistance to coolant (typically ethylene glycol/water mixtures such as G12, G13)

The VW TL 52682 standard involves rigorous testing on finished parts (approximately 24 parts are required for full qualification):

• Refrigerant resistance/hydrolysis test: Long-term exposure to refrigerant mixtures (typically 1000+ hours at 135 degrees).
• Static long-term testing: Pressure and temperature aging.
• Leakage test: Internal pressure test.
• Dimensional stability test: After heat aging.
• Impact and mechanical tests at room temperature and low temperatures.
• Appearance and workmanship quality test: Absence of critical cracks, voids, or defects on the sealing surfaces.

PA66-GF30 is a popular choice for cooling system components because it offers an excellent balance of the following features:

• High heat resistance
• Good mechanical strength
• Chemical resistance to refrigerants.
• Weight savings compared to metal.

However, this standard PA66 is susceptible to hydrolysis (degradation in hot glycol/water). VW TL 52682 certified materials use hydrolysis-stabilized grades to prevent fiber formation and strength loss throughout the vehicle's lifespan.

The relevant standards are as follows:

• TL 52062: General PA66-GF30 for coolant-free applications.
• VW 50133: PA66-GF30 parts without coolant.
• TL 774 standard series: Coolant specifications (G12, G13, etc.)
• VW 01155: Initial sample approval process

The VW TL 52682 standard remains a critical benchmark in the automotive industry for ensuring reliable and long-lasting plastic cooling system components in vehicles.

The VW TL 52682 standard is necessary because it ensures that plastic materials used in automotive cooling systems can withstand the extreme thermal, chemical, and mechanical stresses inside modern vehicle engines. The main reasons this standard is important are as follows:

• High temperature resistance: Cooling system components such as radiator end tanks, cooling pipes, and expansion tanks operate continuously at temperatures around 120-140 degrees Celsius. Materials that cannot withstand these temperatures may soften, crack, or lose strength over time. This standard defines the requirements for materials that maintain their durability under prolonged heat exposure.
• Hydrolysis protection: Engine coolants typically contain mixtures of ethylene glycol and water. These fluids can chemically attack polymers through hydrolysis, especially at high temperatures. This standard ensures that PA66 materials resist degradation when exposed to hot coolants for extended periods.
• Preventing cooling system failures: Cooling system components are critical for safety. If a plastic part carrying coolant fails, it can cause the following:
  • Coolant leak
  • Engine overheating
  • pressure loss
  • Reduced engine efficiency.
  • Potential engine damage.

This standard includes pressure cycling and long-term aging requirements to verify that components remain reliable throughout the vehicle's service life.

• Mechanical strength under pressure: Cooling systems are subjected to repeated pressure fluctuations during heating and cooling cycles. This standard includes the following tests:
  • Pressure vibration test
  • Static long-term pressure test
  • Thermal aging assessments

These tests confirm that reinforced PA66 materials maintain adequate mechanical integrity under real-world operating conditions.

For many years, our organization, with its competent and experienced team, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services compliant with the VW TL 52682 standard.