Glycol systems commonly use ethylene glycol or propylene glycol mixed with water. Concentration, inhibitors and temperature influence compatibility.
EPDM is frequently a suitable candidate for water-glycol mixtures. Some NBR, FKM and PU compounds can also be appropriate, but suitability cannot be assumed from the family name.
Check the coolant manufacturer's formulation and the seal supplier's compatibility data. Additives, oxygen, pressure cycling and long-term ageing may change performance.
For an existing installation, confirm the seal material and application before substituting a different elastomer.
A seal for glycol at 90 °C: what needs checking?
‘Glycol at 90 °C’ is not enough to approve a seal. State whether 90 °C is the normal operating temperature or a short peak, and provide the fluid product name and datasheet. EPDM is a candidate for assessment, not automatic approval of every EPDM compound.
Checklist for an accurate enquiry
- Fluid product name, ethylene or propylene glycol, and concentration in water.
- Inhibitors and other additives, including possible contact with oil or cleaning agents.
- Minimum, normal and maximum temperatures, including peak duration.
- Operating pressure, pressure cycles, and static or dynamic duty.
- Seal type, part reference or ID × CS, groove dimensions, quantity and requested delivery date.
- Material documentation requirements and any testing of the exact compound.
Investigating a leak in an existing system
Send photos of the seal and installation, the previous material specification and a description of when the leak occurs. State whether the fluid, concentration, temperature or cleaning process has changed. A used seal can be deformed; compare measurements with the drawing and groove.
Request an assessment of the exact compound and fluid combination. A general material chart or a more expensive material alone does not demonstrate that the problem has been resolved.
General technical guidance, not approval for a specific application. Confirm material grade, dimensions and suitability for actual operating conditions.
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