When you observe sealant oozing or seeping from the joint after the system is pressurized, it means the sealant layer—which should be a cured, durable polymer—is either too weak to resist the force or is still liquid. This failure is a direct result of one of the two following issues: Insufficient Clamping Force (Improper Torque) or Cure Inhibition (Liquid Sealant).
1. The Primary Cause: Insufficient Clamping Force (Under-Torque)
Anaerobic sealants require the flanges to be mated tightly to function correctly.
| Mechanical Problem | Why it Fails | Result (Oozing) |
| Under-Torque | The bolts were not tightened to the manufacturer’s specification, leading to insufficient clamping force on the joint. | Internal pressure finds the path of least resistance and pushes the sealant right out of the joint, often leading to a complete blowout failure. |
| Flange Warpage | The flanges are not flat, so the clamping force is concentrated on high spots, leaving a wide, uncompressed gap in other areas. | The sealant in the wide, uncompressed gap is extruded out when fluid pressure hits that weak point. |
The Fix: Always use a calibrated torque wrench and follow the manufacturer’s specific cross-hatch sequence and torque values. The high clamping force is what contains the sealant.
2. The Secondary Cause: Cure Inhibition (Liquid Sealant)
If the sealant is oozing and it feels tacky or liquid, it failed to cure in the first place. A liquid material cannot resist any significant pressure.
| Chemical Problem | Why it Fails | Result (Oozing) |
| Contamination | Oil, grease, or a non-metallic coating (paint, lacquer) prevented the sealant from contacting the metal catalyst. | The material remains liquid and simply washes out or is pushed out of the joint once pressure is applied. |
| Passive Metal | The metal (e.g., aluminum, stainless steel) did not provide enough metal ions to start or accelerate the cure reaction. | The reaction is too slow; the assembly is pressurized before the sealant has reached its full 5.2 N/mm2compressive strength, leading to failure. |
The Fix: Meticulously clean both surfaces to bare metal. If using a passive metal, you must use an anaerobic activator and allow the full 24 hour cure time before pressurizing the system.
Incure HeatGrip™ 504 Flexible General Purpose Gasket Sealant
For seals that must resist high fluid pressure, we recommend Incure HeatGrip™ 504 Flexible General Purpose Gasket Sealant.
The 504 is designed to cure into a strong, durable, but flexible polymer with a compressive strength of 5.2 N/mm2. When properly cured and contained by correct flange torque, this strength is more than sufficient to resist the internal pressures found in engine, transmission, and hydraulic systems up to 150∘C.
Remember: Sealant oozing under pressure is a sign that the mechanical integrity of the joint (torque) or the chemical integrity of the sealant (cure) has failed. Reassemble only after addressing both.