LOSTAR Heavy Duty 603-5403 coolant reservoir front view for overflow control.
LOSTAR Heavy Duty 603-5403 reservoir side view supports quick level checks.
LOSTAR Heavy Duty 603-5403 cap included ensures secure sealing.
LOSTAR Heavy Duty 603-5403 coolant bottle clear body allows level inspection.
LOSTAR Heavy Duty 603-5403 reservoir with hose connections enables straightforward replacement.
LOSTAR Heavy Duty 603-5403 fits Kenworth Peterbilt models across years.
LOSTAR Heavy Duty 603-5403 durable plastic reservoir for long service life.
LOSTAR Heavy Duty 603-5403 coolant reservoir front view for overflow control.
LOSTAR Heavy Duty 603-5403 reservoir side view supports quick level checks.
LOSTAR Heavy Duty 603-5403 cap included ensures secure sealing.
LOSTAR Heavy Duty 603-5403 coolant bottle clear body allows level inspection.
LOSTAR Heavy Duty 603-5403 reservoir with hose connections enables straightforward replacement.
LOSTAR Heavy Duty 603-5403 fits Kenworth Peterbilt models across years.
LOSTAR Heavy Duty 603-5403 durable plastic reservoir for long service life.

LOSTAR Heavy Duty 603-5403 Coolant Overflow Reservoir Bottle for 2008-2017 Kenworth & Peterbilt Trucks | T680 T800 W900

OverviewThe LOSTAR Heavy Duty 603-5403 coolant overflow reservoir bottle is designed as a drop-in replacement for many...
Vendor: LOSTAR
Availability: In stock
£182.10
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LOSTAR Heavy Duty 603-5403 coolant reservoir front view for overflow control.

LOSTAR Heavy Duty 603-5403 Coolant Overflow Reservoir Bottle for 2008-2017 Kenworth & Peterbilt Trucks | T680 T800 W900

£182.10
LOSTAR Heavy Duty 603-5403 coolant reservoir front view for overflow control.
LOSTAR Heavy Duty 603-5403 reservoir side view supports quick level checks.
LOSTAR Heavy Duty 603-5403 cap included ensures secure sealing.
LOSTAR Heavy Duty 603-5403 coolant bottle clear body allows level inspection.
LOSTAR Heavy Duty 603-5403 reservoir with hose connections enables straightforward replacement.
LOSTAR Heavy Duty 603-5403 fits Kenworth Peterbilt models across years.
LOSTAR Heavy Duty 603-5403 durable plastic reservoir for long service life.

LOSTAR Heavy Duty 603-5403 Coolant Overflow Reservoir Bottle for 2008-2017 Kenworth & Peterbilt Trucks | T680 T800 W900

£182.10
Description
Description
x

Overview

The LOSTAR Heavy Duty 603-5403 coolant overflow reservoir bottle is designed as a drop-in replacement for many Kenworth and Peterbilt trucks built between 2008 and 2017. In everyday driving, it helps capture excess coolant during heat cycles, aiding level maintenance and reducing spill risk on busy highways or long hauls.

Engineered for durability, this bottle is specified to fit models powered by Cummins or CAT engines within the listed lineup. The rugged plastic construction is designed to withstand varied road conditions, temperature shifts, and regular servicing requirements.

Key compatibility

  • Fits 2008–2017 Kenworth and Peterbilt trucks as a direct replacement
  • Compatible with Cummins or CAT engine configurations within the family
  • Includes cap for a complete, ready-to-install assembly

Design and build

  • Brand new radiator overflow bottle with sturdy plastic construction
  • Direct replacement that aligns with factory mounting points and hose connections
  • Built to strict quality control standards to ensure consistent fitment

Usage and maintenance

In daily use, it supports coolant level management during temperature cycles and simplifies routine checks thanks to a clear body design. It serves as a practical upgrade for aging reservoirs and for fleets managing spares.

Maintenance tips

  • Inspect hose connections for wear during service intervals
  • Ensure the cap seals tightly after installation to prevent leaks
  • Keep an eye on reservoir level and replace as needed to maintain margins

Note: The dealer part number N5346001 is replaced by this product when performing a straightforward swap, helping keep your cooling system operation consistent without requiring additional parts.

FAQ

Q: What vehicles is this reservoir compatible with?

A: Designed for 2008–2017 Kenworth and Peterbilt trucks, including common T680, T800, and W900 series.

Q: Does the kit include a cap and is it a direct replacement?

A: Yes, it includes a cap and is built as a direct replacement for the original reservoir.

Shipping & Return
Shipping & Return
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Returns Policy

You may return most new, unopened items within 30 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.

Shipping

We can ship to virtually any address in the world. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.

When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.

Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.

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