Coolant Reservoir Cap - 21 lb Reservoir Side - Freightliner Cascadia P4 05-32312-000 572.2044

Hold cooling-system pressure where it belongs with this 21 lb Coolant Reservoir Cap distributed by FleetPro Parts & Tires. It is the reservoir-side cap for the Freightliner Cascadia P4, 2018-2024, and it is the part most often overlooked when a truck starts losing coolant nobody can find on the ground. A cap with a worn seal or the wrong pressure rating bleeds off system pressure, drops the boiling point of the coolant, pushes fluid out of the overflow, and fails the shop's pressure test every single time. Manufactured by Automann to Fleet Standard specifications, this cap is stocked heavily right here in our Hanover Park, Illinois warehouse for lightning-fast shipping to fleets, diesel repair shops, and owner-operators nationwide.

Pressure Held, Coolant Kept: The 21 lb Cascadia P4 Cap Advantage

A pressurised cooling system runs hotter than boiling without boiling, and the cap is the only thing making that true. This one is rated at 21 psi, the rating specified for the Cascadia P4 reservoir side, so the system reaches operating temperature and holds it instead of purging coolant into the overflow every time the truck pulls a grade. Fit a cap rated too low and you give that margin away; fit one rated too high and you load the hoses, the reservoir seams and the radiator with pressure they were never built to see.

The sealing surfaces are what age out. The rubber hardens, takes a set, and stops sealing against the filler neck long before anything looks obviously wrong, which is why a slow and unexplained coolant loss so often ends at the cap. Replacing it during a coolant service is the cheapest step in the entire job, and it is the difference between a pressure test that holds and an afternoon spent chasing a leak that was never there.

At FleetPro Parts & Tires, we keep the numbers straight so you order once. This cap is a direct replacement for highly searched industry numbers including Freightliner 05-32312-000 and its unhyphenated form 0532312000.

Vehicle Fitment & Compatibility

This heavy-duty aftermarket coolant cap is intended for the following commercial application:

• Make/Model: Freightliner Cascadia P4, 2018-2024
• Position: Reservoir side
• Pressure Rating: 21 psi (21 lb)
• Component Group: Cooling System / Reservoirs & Fluid Tanks

Direct Replacement & Cross-Reference Numbers:

This Automann coolant reservoir cap serves as a direct replacement for the following part numbers:

• Freightliner Interchange: 05-32312-000, 0532312000
• Automann Distributor #: 572.2044

Technical Specifications

• Component Type: Coolant Reservoir Cap
• Position: Reservoir Side
• Pressure Rating: 21 psi (21 lb)
• Fits: Freightliner Cascadia P4, 2018-2024
• Weight: 0.13 lbs
• Package Dims: 3.2 x 3.2 x 1.65 in
• Warranty: 1-Year FleetPro Warranty
• Product Level: Fleet Standard Aftermarket
• Brand: Automann (Distributed by FleetPro Parts & Tires)