What You're Actually Buying
This is the lower hose running from the radiator outlet down to the water pump inlet on International ProStars. The inner spring matters here - lower hoses see negative pressure when the pump's pulling coolant through, and without that spring wound inside the rubber, the hose walls can pinch shut and starve the pump. Cheap non-reinforced hoses will get you a truck sitting on the shoulder with a temp gauge pegged.
2.5" ID is specific to this application - don't guess on this one. If your old hose measures different, this isn't your part regardless of what year truck you've got, because International ran a couple different diameters across ProStar production depending on engine and cooling package.
Reading the Cross Reference
3840364C1 is Navistar's number, and you'll see it written as 3840-364-C too - same part, dealers just format it different ways. Newstar carries it as IH-3840-364-C or S-28858, and that's their aftermarket line built to the same Navistar spec, not International parts themselves.
Gates 42771956 and Automann 561.55364 are aftermarket manufacturers making a hose that fits this same bend pattern and ID. Duralast F11538 is another aftermarket option you might find at a parts store counter. All of these are supposed to interchange for this application, but hose molds change and suppliers update tooling, so a number that crossed clean two years ago can shift.
Bottom line - pull your old hose and check the ID with a tape measure, and look for any part number stamped or molded into the rubber near the clamp end. That's your fastest confirmation. If it's illegible, get us your VIN and we'll pull it from there.
Ordering From PartStop
We're in Tacoma and keep this hose in stock for same-day pickup or same-day ship if you call before early afternoon. Fleet guys running ProStars up and down I-5 know this hose fails right when you need the truck moving, so we don't sit on backorders for this one.
Comes with our 6+ month warranty. If it shows up and doesn't match your old hose's bend or length, call the counter before you cut clamps off - we'll sort the right number instead of you eating a return on a modified hose.
3840364C1 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 3840364C1. Use them to identify the part — then confirm the exact fit by VIN or the number stamped on your old unit before you order. An interchange is a starting point, not a fitment guarantee.
| Brand / Line | Cross-Reference Numbers |
|---|---|
| Navistar | 3840-364-C |
| Gates | 42771956 |
| Automann | 561.55364 |
| Genuine Newstar | IH-3840-364-C, S-28858 |
| Duralast | F11538 |
| International Harvester (IHC) | F02512S352 |
Frequently asked questions
Does 3840364C1 fit my ProStar?
Depends on the cooling package your truck came with. This hose fits the F02512S352 spec specifically - give us your VIN or the number off your old hose and we'll confirm before you order.
Is this the same as the Gates 42771956?
Gates 42771956 is built to cross with this Navistar number, so it should fit the same application. It's a different manufacturer making the part to spec, not a Navistar-produced hose. Compare ID and length against your old hose if you're not sure.
Why does the inner spring matter on a lower hose?
Lower hoses run under suction from the water pump, and without that wire spring reinforcement the hose can collapse on itself under vacuum, cutting off coolant flow. You'll see it as overheating that comes and goes with RPM.
Not sure it fits? We check before you pay.
Run your VIN and we’ll match parts to your exact truck, or call the counter — a person who knows trucks verifies fitment by OEM number before the order ships. No wrong-box returns.
More cross-reference guides
Need the part, not just the reading?
Every part below is a Premium Quality aftermarket Direct Replacement with published OEM cross-reference numbers, a 6+ month warranty and same-business-day shipping from Tacoma, WA. Not sure it fits? Run your VIN — or call and a person who knows trucks will verify fitment before you pay.