Western Star 4900 Coolant Hoses 1988–2026
Silicone coolant hoses, radiator hoses and molded elbows — 4-ply reinforced replacements matched by inner diameter and OEM number, the fix for the most common roadside coolant failure. The 4900 is Western Star's severe-service conventional — logging, oilfield and heavy-haul duty in production since the late 1980s.
In Stock30% OFFPartStop
Universal Silicone Hump Hose Coupler - 2" ID x 6" Length - 4-Ply Reinforced for Turbo, Intake & Coolant F02484S352
OEM F02484S352
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EGR Silicone Reducer Hose for Cummins ISX15 - 57mm to 48mm ID - Aramid Reinforced with Stainless Steel Ring F02486S352
OEM 3687223
In Stock30% OFFPartStop
90-Degree Molded Elbow Hose - 1.00" ID - Fits Detroit Diesel Series 50 & 60 - Replaces 23518315,F02518S352
OEM 23518315
In Stock30% OFFPartStop
Molded Crankcase Breather Hose - 1.00" ID - Fits Cummins ISX15 & QSX15 - Replaces 4298695, 3427229,F02519S352
OEM 4298695
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11549 Hose Separator Heavy Duty Trucks 100469D 1004690 10QE125P1 5396-11549
OEM 11549
Coolant hose diagram — how the legs connect
| # | Hose | Typical ID | Runs from / to |
|---|---|---|---|
| 1 | Upper radiator hose | 2.5" ID typical | Thermostat housing to radiator inlet |
| 2 | Lower radiator hose | 2.5" ID typical | Radiator outlet to water pump |
| 3 | Surge tank fill line | 0.75"–1" ID | Expansion tank to radiator top tank |
| 4 | Deaeration line | 0.75" ID | Expansion tank to water pump inlet |
| 5 | Heater hoses | 0.75" ID | Engine to cab heater core and back |
| 6 | CAC hot side | 4" ID typical | Turbo outlet to charge air cooler |
| 7 | CAC cold side | 4" ID typical | Charge air cooler to intake manifold |
Western Star 4900 Coolant Hoses (1988–2026) — what we stock
Coolant hoses are the quiet killer on a working truck: they look fine right up until a soft spot lets go on a grade and the temp gauge pins. Factory rubber on a Western Star 4900 of this era has seen years of heat cycles, so squeeze a hose near the clamps, and if it feels crunchy or gummy it is telling you something. We stock 65 cooling hoses and belts, and the silicone in that range is 4-ply reinforced and matched by inner diameter and OEM number. Silicone shrugs off the heat that hardens EPDM rubber, which is why it is the standard upgrade rather than just a repair.
The 4900 is Western Star's severe-service conventional — logging, oilfield and heavy-haul duty in production since the late 1980s.
How to pick the right part for your 4900
Inner diameter is the number that decides the job, and our range clusters into a handful of sizes: 2.5 in and 4 in are the two biggest groups at ten hoses each, then 3 in with seven, 3.5 in and 2 in with four each, and 2.25 in with three. Small heater and P-pipe lines run 0.75 in and 1 in. If your Western Star 4900 is an International or a Volvo, check for a metric number instead: those builds use 82 mm, 100 mm and 57 mm bores, and reducers such as 100 mm to 85 mm or 100 mm to 83 mm are their own part numbers, not a size you can round to the nearest inch.
Why buy coolant hoses from PartStop
Every part on this page is Premium Quality aftermarket — a Direct Replacement matched to factory mounting points and backed by a 6+ month warranty. We publish the OEM cross-reference numbers right on the listing (most sellers hide them), we verify fitment by OEM number or VIN before you buy, and orders placed on business days ship same day from our warehouse in Tacoma, WA. Hoses are stocked and ship same business day, because a truck down on coolant should not wait a week for rubber. If anything about fitment is unclear, call the counter at (253) 600-1351 — a person who knows trucks answers.
Western Star 4900 Coolant Hoses — FAQ
What size coolant hose does my Western Star 4900 take?
Measure the inner diameter of the old hose, not the outer. Across our range the common sizes are 2.5 in and 4 in (ten hoses each), 3 in (seven), 3.5 in and 2 in (four each) and 2.25 in (three), with 0.75 in and 1 in for heater and P-pipe lines. Molded hoses also step between sizes, such as a Z-shape upper that goes 2.50 in to 2.37 in, so check both ends before ordering.
Silicone vs rubber — is silicone worth it?
For a truck that works, yes. Silicone tolerates sustained heat that hardens and cracks EPDM rubber, so it is typically the last set of hoses the truck needs. The price difference is small next to one tow bill.
What is a CAC hose and is it the same as a coolant hose?
No, and mixing them up is a costly mistake. A charge air cooler hose carries hot pressurised air between the turbo, the cooler and the intake, not coolant. Of our 65 cooling hoses, 27 are the CAC family — hump hoses, bellows and reducers — and those run mostly 4 in (eight of them), then 3.5 in and 3 in with three each. A coolant hose in a CAC position will balloon and blow off.
How many stainless rings should a hump hose have?
The ring count goes with the length and the pressure, not with quality. A short 4 in x 6 in hump usually carries two rings, a 4 in x 8 in carries three, and the long bellows hoses run four to six or more across a 12 to 19 in span. Match the ring count on the old hose: fewer rings on the same span means it can collapse under vacuum.
How do I find the right hose for my Western Star 4900?
OEM number first — it is on the listing as a cross-reference and usually printed on your old hose. If the number is unreadable, match shape and inner diameter from your parts diagram, or send us your VIN and we will verify.
Should I replace clamps with the hoses?
Always. Constant-torque clamps are designed for silicone's expansion cycle; old worm clamps bite unevenly and weep. It is a few dollars that decides whether the job holds.
One hose failed — do I replace the rest?
They have all lived the same heat cycles. If the truck is staying in your fleet, a full set is cheap insurance; at minimum, squeeze-test every hose while the coolant is already drained.