GME 60259 Cold Resistance of Elastomers

Developed by General Motors Europe (GME), the “GME 60259 Cold Resistance of Elastomers” standard is a materials testing standard used to evaluate the performance of elastomeric materials after exposure to low temperatures. Elastomers are widely used in vehicles in gaskets, seals, hoses, air seal strips, bushings, vibration dampers, and flexible fasteners. Because these components often operate in extremely cold climates, maintaining their mechanical properties is crucial for vehicle safety and durability.

This standard describes a laboratory procedure for exposing elastomer samples to specified low temperatures for a predetermined period and then evaluating changes in their physical properties. However, this standard was not designed for new global vehicle programs and was subsequently replaced by the ISO 23529 standard. Nevertheless, it remains applicable to certain legacy or ongoing programs.

The primary purpose of the GME 60259 standard is to determine whether an elastomer can retain its functional properties after being exposed to cold environmental conditions. This test method helps engineers determine the following:

• Resistance to cold-related brittleness
• Changes in hardness after exposure to cold.
• Flexibility at low temperatures
• Suitable for use in cold climates.
• Durability of the material throughout the vehicle's lifespan.

This standard is particularly valuable for verifying the rubber materials used in vehicles sold in regions experiencing severe winter temperatures.

The GME 60259 standard applies to numerous elastomeric materials, including:

• Natural rubber (NR)
• Ethylene propylene diene monomer rubber (EPDM)
• Nitrile rubber (NBR)
• Silicone Rubber
• Chloroprene rubber (CR)
• Fluoroelastomers (FEM)
• Thermoplastic elastomers (TPE)

Typical automotive applications of this standard include:

• Door and window seals
• O-rings
• Engine gaskets
• Fuel system gaskets
• Vacuum hoses
• Suspension bushings
• Protective bellows
• Heating, ventilation and air conditioning (HVAC) seals

The described test method measures, in principle, how exposure to low temperatures affects the properties of elastomers. In general, the test follows these steps:

• Preparation of standardized test samples.
• Conditioning the samples at a sub-zero temperature for a specific period of time.
• Removing the samples from the cold environment.
• Measuring changes in mechanical properties.
• Comparing the results with the original values.

The aim is to simulate the environmental conditions encountered when driving a vehicle during the winter months.

After being exposed to cold, the material is typically evaluated in terms of the following aspects:

• Change in hardness: Hardness is usually measured using the Shore hardness method. An excessive increase in hardness indicates a loss of elasticity.
• Bending test: This standard assesses brittleness, typically using bending tests. Samples are bent after cold conditioning to determine if cracking or fracture occurs.
• Visual inspection: Inspectors examine the samples from the following perspectives:
  • Surface cracks
  • Cracks
  • Permanent deformation
  • Whitening
  • Material damage
• Elastic recovery: The ability of an elastomer to return to its original shape after deformation can also be evaluated, depending on the component requirements.

Rubber components become harder as temperatures drop. When an elastomer loses too much of its elasticity, several problems can arise:

• Leakage
• Water inlet
• Air leak
• Increased cabin noise
• Reduced vibration isolation.
• Component cracking
• Early failure

The GME 60259 standard helps manufacturers identify materials that can maintain their performance in winter operating conditions.

This standard is generally applied in the qualification of the following:

• Door sealing systems
• Luggage seals
• Sunroof seals
• Engine compartment rubber parts
• Fuel system components
• Cooling system hoses
• Air intake hoses
• Chassis rubber components
• Electrical connection gaskets

The various advantages provided by the GME 60259 standard are as follows:

• Simulates real-world cold weather conditions.
• Identifies fragile materials before production.
• It improves vehicle reliability.
• It supports material selection for global markets.
• It helps reduce warranty claims.
• It provides repeatable laboratory evaluation.
• It allows for the comparison of alternative elastomer compounds.

The GME 60259 standard works in conjunction with various related elastomer testing standards, including:

• Determination of indentation hardness (Shore A and D) using the GME 60252 Durometer method.
• ISO 23529 Rubber - General procedures for the preparation and conditioning of test specimens for physical testing methods.
• ISO 188 Rubber, vulcanized or thermoplastic - Accelerated aging and heat resistance tests
• ISO 37 Rubber, vulcanized or thermoplastic - Determination of tensile stress-strain properties
• ASTM D2240 Standard test method for rubber properties - Durometer hardness
• ASTM D746 Standard test method for determining the temperature of brittleness of plastics and elastomers by impact method.

Although developed for General Motors Europe, the GME 60259 standard test principles are also applied in the following sectors:

• Automotive production
• Commercial vehicles
• Agricultural machinery
• Construction equipment
• Aviation and space
• Industrial machinery
• Rail Transportation

Using the GME 60259 standard enables manufacturers to:

• To verify cold weather resistance.
• Comparing different rubber formulations
• Increasing product reliability
• Meeting OEM qualification requirements
• To reduce failures occurring in the field.
• Supporting quality assurance during production.

In conclusion, the GME 60259 standard is a crucial test method for evaluating the cold resistance of elastomers used in automotive applications. By measuring changes in hardness and assessing brittleness after controlled low-temperature exposure, this standard helps ensure rubber components remain flexible, durable, and functional in harsh winter conditions. While newer GM programs are transitioning to the ISO 23529 standard, the GME 60259 standard remains a valuable reference for understanding older projects and GM's historical material qualification practices.

For many years, our organization, with its competent and experienced staff, 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 GME 60259 standard.