VW TL 52361 Aramid Reinforced Coolant Hoses - Material and Functional Requirements

The standard "VW TL 52361 Aramid reinforced coolant hoses - Material and functional requirements" developed by the Volkswagen automobile company specifies the requirements for elastomer compounds used for hoses in the coolant circuit. The hoses are suitable for temperatures occurring in the cooling system (minus 40 degrees to plus 150 degrees, briefly up to 160 degrees). The hoses are also available with an inner layer stabilized against electrochemical corrosion.

According to this standard, the general requirements are as follows:

• The approval of the initial supply and changes must comply with the VW 01155 standard.
• The environmental requirements specified in the VW 91100 standard must be met.
• Material suitability must be in accordance with the VW 91101 standard.
• For full testing, 10 finished parts (larger design) and 20 finished parts (smaller design) are required.
• Tests should be performed on samples taken from finished parts.

The inner surface of the hose must be flawless and must not show any irregularities. The entire structure must be free from defects such as bubbles or inclusions in the rubber as well as fabric defects. The hoses must be free from stains, bleached areas, crystalline deposits and gray cast. The individual layers must be properly bonded even after contact with the medium. The hoses must be free from separating agents and foreign matter such as rubber particles and fabric fibers.

The working pressure range should be between 0 bar and 2,4 bar positive pressure according to the drawing.

The inner layer thickness of the hoses should be 60% to 70% of the total wall thickness. It should have a strong structure and an outer layer.

Inner layer materials and outer layer materials shall be optionally EPDM (synthetic rubber), or cross-linked EPM (ethylene propylene copolymer) (in accordance with “ISO 1629 Rubber and tyres - Nomenclature”). Reinforcement materials shall be aramid (knitted fabric).

The requirements for material properties are given in the table given in the standard as follows:

• Thermogravimetry (according to PV 3927 standard)
• Density (according to ISO 1183-1 standard)
• Pyrolysis gas chromatography/mass spectrometry (according to PV 3935 standard
• Zinc content (determined by the disintegration method (sulfuric/nitric acid), zinc concentration is measured using atomic absorption spectroscopy or inductively coupled plasma (analysis)
• Hardness (according to ISO 48-4 standard, as received, after thermal aging at 160 degrees for 96 hours, after aging in coolant at 160 degrees for 96 hours, after aging in diesel fuel at 23 degrees plus/minus 2 degrees for 46 hours)
• Tensile strength (according to DIN 53504 standard, as received, after thermal aging at 160 degrees for 96 hours, after aging in coolant at 160 degrees for 96 hours, after aging in diesel fuel at 23 degrees plus/minus 2 degrees for 46 hours)
• Elongation at tear (according to DIN 53504 standard, as received, after thermal aging at 160 degrees for 96 hours, after aging in coolant at 160 degrees for 96 hours, after aging in diesel fuel at 23 degrees plus/minus 2 degrees for 46 hours),
• Tension value (at 53504 percent elongation according to DIN 100 standard.
• Weight change (after aging in coolant at 160 degrees for 96 hours, after aging in diesel fuel at 23 degrees plus/minus 2 degrees for 46 hours)
• Determination of residue (according to PV 3339 standard, after aging in coolant at 160 degrees for 96 hours)
• Tear propagation resistance (according to DIN ISO 34-1 standard method A, after thermal aging at 160 degrees for 96 hours, after aging in coolant at 160 degrees for 96 hours)
• Volume resistance (according to DIN EN 62631-3-1 standard)
• Electrochemical resistance of the inner layer (only for TL 52361 electrolytic capacitor) (the coolant/water ratio of the current design is 50:50, voltage 10V, time 10 days, temperature 100 degrees).

The requirements for the properties of finished parts are given in the table given in the standard as follows:

• Odor (there should be no objectionable inherent odor)
• Ozone resistance according to VW 2.8.1 standard (must be free of cracks)
• Behavior in cold air bending test (according to VDA 675-254 standard, 40 hours at minus 22 degrees) (must be elastic, no cracking or breaking)
• Plastic deformation according to PV 3307 standard (during aging, the area around the hammer edge of the sample should not be torn, after 160 hours of thermal aging at 22 degrees, it should be at most 75 percent)
• Adhesion strength per mm of sample width according to DIN 53530 (the lowest peak force shown in the diagram must meet this requirement) (as received at least 2,5 in strength, must be at least 160 strength after aging in coolant for 96 hours at 2 degrees and at least 23 strength after aging in diesel fuel for 2 hours at 46 degrees plus/minus 0,5 degrees)

To prepare the sample, a strip knife separation machine is used and the outer and inner layers of the coolant hose are separated.

Among the numerous tests, measurements, analyses and evaluations carried out for businesses in various sectors, our organization also provides testing services defined in the “VW TL 52361 Aramid reinforced coolant hoses - Material and functional requirements” standard with its trained and expert staff and advanced technological equipment.