ASTAMOTOR Front Engine Coolant Reservoir for Kenworth & Peterbilt — 603-5403, Durable Direct-Fit

ASTAMOTOR's 603-5403 front engine coolant reservoir is a direct-fit replacement expansion tank engineered to restore your Kenworth or Peterbilt cooling system reliability.

If the original coolant recovery tank on your heavy-duty truck has cracked, warped, or started leaking, replacing it with a quality, compatible unit prevents coolant loss and helps maintain proper cooling system pressure. This ASTAMOTOR reservoir corresponds to OE reference numbers 603-5403, 6035403, N5346001 and T1673008 and is molded from durable plastic designed to resist expansion and cracking under heavy thermal cycles typical of diesel rigs.

Will this reservoir fit my truck model?

Yes — this ASTAMOTOR reservoir is made to match the original dimensions and mounting points of the listed Kenworth and Peterbilt models. Always verify the OE part numbers or compare the old tank to ensure identical inlet/outlet locations and bracket positions before purchase.

• Direct replacement for OE 603-5403 / 6035403 / N5346001 / T1673008
• Compatible Kenworth: T600 (2008–2015), T660 (2008–2017), T800 (2008–2017), W900 (2008–2017)
• Compatible Peterbilt: 348, 365, 367, 377, 382, 384, 385, 386, 388, 389 (various 2008–2018 model years)
• Check hose fitting positions and mounting tabs to confirm fit

How durable is the ASTAMOTOR coolant recovery tank?

The tank is manufactured from high-quality plastic formulated to withstand repeated heating and cooling cycles without excessive deformation. That resilience reduces the chance of cracks or leaks over years of service, which is particularly important for long-haul and heavy-load operation.

• Premium plastic resists thermal expansion and cracking
• Precision-molded inlet/outlet and mounting points for a secure fit
• Material selected for long-term exposure to coolant and heat

How easy is installation and what should I expect?

Installation is straightforward because this is a direct replacement designed to use the same mounting points and hose connections as the factory tank. Typical replacement requires basic hand tools and can often be completed in minutes once the old tank is removed and hoses disconnected.

• Direct bolt-in replacement — no modification required
• Swap hoses and fasteners from the original tank to the new unit
• Bleed and top up coolant per manufacturer procedure after install

What function does the coolant expansion tank perform?

The recovery tank captures expanding coolant when the engine warms and returns it to the system as the engine cools, helping maintain proper coolant level and pressure balance. A reliable reservoir prevents air pockets and reduces the risk of overheating due to coolant loss.

• Balances cooling system pressure during thermal cycles
• Stores and returns coolant to prevent air entry into the system
• Helps maintain correct coolant level to support engine temperature control

Who is this for: Truck owners, fleet managers, and professional technicians who operate or maintain Kenworth T600/T660/T800/W900 and multiple Peterbilt models (listed above) and need a dependable, OEM-matching coolant recovery tank. Choose this ASTAMOTOR unit when you want a durable, direct-fit replacement that restores system integrity and reduces the chance of leaks or overheating due to a compromised reservoir.