The SPOOLOGIC Crankcase Ventilation (CCV) Oil Separator Line SL-350-027 is a direct-replacement CCV oil separator line for 6.6L Duramax L5P (2024-2026) applications. Built to OE form and fit, it routes crankcase blow-by vapor through the CCV oil separator system. Ships complete with the sealing hardware required to complete the install in one job. Backed by a 1-Year Limited Warranty.

Why You Replace the CCV Line — Not Just the Seals

Oil lines and their sealing hardware are not designed to be reused forever. Here’s what’s actually happening to the parts you’re tempted to put back:

• OE CCV/oil separator lines clog. The line routes crankcase blow-by vapor through the oil separator and back into the intake. Over time, oil vapor coats the inside of the line, restricts flow, and drives up crankcase pressure — you’ll see rear main leaks and valve cover weeps as the first symptom.
• Molded plastic and rubber sections crack. The line lives in the engine bay and sees the same thermal cycling as every other underhood component. Molded elbows crack at stress risers, and rubber sections split at the crimps.
• Seals are single-use. Any O-ring or gasket that gets torqued down takes a permanent compression set the moment it’s installed. Reused seals weep crankcase vapor and oil.
• Cracked CCV lines cause driveability issues. A crack anywhere on the CCV path causes unmetered air into the intake — codes, rough idle, and long-term MAF sensor contamination from oil vapor.

Component Breakdown — What Each Piece Does

• 1 CCV oil separator line assembly — molded plastic and rubber line formed to OE geometry, routes crankcase vapor from the valve cover through the separator to the intake.
• Pre-installed O-rings — seal the line to the CCV separator and intake ports.

Material Technology — Why Each Material Was Chosen

• Formed steel line body — the line is bent to OE geometry so it clears the surrounding components and drops into the factory brackets without modification.
• OE-spec sealing hardware — the included crush washers, O-rings, or gaskets are the correct material and durometer for the oil temperatures and pressures this line sees in service.
• Heat-treated steel bolts and fittings — every threaded fastener in the kit is the correct grade, length, and thread pitch for the port it goes into.

Install Notes

• Clean the intake-side and separator-side mating surfaces with a lint-free rag before installing the new line. Old oil residue on the mating faces will keep the new O-rings from sealing.
• Install the new O-rings dry — no RTV, no thread sealant. The seals are designed to seal on clean, flat metal.
• Start all fittings by hand before torquing anything.
• Follow the OE service manual torque specs. Over-torque cracks the plastic housings; under-torque leaks and pulls unmetered air.
• Route the line through the factory brackets so it doesn’t rub against moving components.
• Clear any CCV codes and inspect after a full heat cycle — a leak here pulls fuel trims off spec.

What’s Included

• 1 CCV oil separator line assembly with pre-installed O-rings

Interchange / Cross-Reference

• GM OEM 12739532 — cross-reference

Features

• Direct-replacement CCV oil separator line for 6.6L Duramax L5P (2024-2026) applications
• Ships with the sealing hardware required to complete the install
• OE form and fit — direct replacement, no modifications
• Backed by a 1-Year Limited Warranty

Fits 2025-2026 6.6L Duramax

• 2025 – 2026 Chevrolet Silverado GMC Sierra 2500 3500 6.6L Duramax L5P
• 2025 – 2026 Chevrolet Silverado 4500 5500 6500 6.6L Duramax L5D

1-Year Limited Warranty

Every SPOOLOGIC crankcase ventilation oil separator line is covered by a 1-Year Limited Warranty against defects in materials and workmanship from the date of purchase. Warranty covers replacement of the part only. Warranty does not cover labor, towing, downtime, consequential damages, failures caused by improper installation, failures caused by dirty or damaged mating surfaces, reuse of any included gasket or O-ring, or use outside the listed fitment.