Crankcase Ventilation Hose Replacement - OEM Only Due to Routing Bends

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Problem

The large molded rubber ventilation hose (Toyota calls it 'Ventilation Hose') that runs from the valve cover oil filler neck area down to the block hardens and cracks after decades, requiring replacement. The hose routes around the alternator with a specific bend that generic hose cannot replicate.

Cracked or hardened large hose running from valve cover area to blockPossible oil vapor leaks or PCV system issues from deteriorated hoseHose visibly degraded after 30+ years

Root Cause

Original rubber ventilation hose (part #12263-42010) deteriorates and cracks with age. This molded hose has a specific bend needed to clear the alternator, which generic bulk oil-rated hose cannot replicate due to its stiffness and internal reinforcement structure.

Confidence

Moderate confidence — Multiple community members agreed on this solution

View Original Thread →Posted August 2021 on SupraForums.com