What This Hose Is and Where It Lives
This is a molded silicone/rubber 90-degree elbow, 1.00" inside diameter, built for coolant routing on Series 50 and Series 60 Detroit engines. Molded hoses hold their shape at the bend better than a straight piece you'd try to force into an angle - that's why Detroit spec'd it molded instead of flex.
On these engines it typically shows up in the auxiliary water pump circuit or a heater/coolant crossover line, depending on the chassis and year. Exact routing varies by application, so don't assume - pull the old hose and match it up before you order.
These crack and go soft with age from heat cycling more than anything else. If yours is hard, checked, or weeping at the bend, that's your sign - not just a leak at a clamp.
Why These Numbers Cross and What to Check
23518315 is the Detroit part number, and F02518S352, Gates 691850, and Dayco 561.99315 all cross to it because they're built to the same ID, wall thickness, and bend geometry. Different manufacturers, same physical part - that's how the aftermarket cross-reference works.
Where guys get burned on hose crosses isn't the ID, it's the leg length on each side of the bend and how tight the radius is. A 90-degree elbow with legs half an inch off can still clamp on, but it'll sit wrong and stress the connections on both ends. Measure leg length off the old hose if you've got any doubt.
Always confirm against the number stamped or printed on your old hose, or pull it by VIN if the hose is gone and you're going off memory. We can't guarantee fitment sight unseen - that's on you to verify before it goes on the truck.
Ordering From PartStop
We're in Tacoma and keep this one in stock for same-day will-call or local pickup. If you're not local, it ships nationwide and we're not going to make you wait a week for a coolant hose.
Comes with our standard 6+ month warranty. If it fails from a material defect, bring it back - we're not going to argue with you about a cracked elbow.
Call the counter with your VIN or the old part number if you're not sure which hose you need. Cheaper to spend two minutes confirming than to reorder and eat the shipping twice.
23518315 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 23518315. 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 |
|---|---|
| Fleetguard | F02518S352 |
| Gates | 691850 |
| Dayco | 561.99315 |
Frequently asked questions
Does 23518315 fit my Series 60 in a Freightliner?
Probably, but Detroit used these engines across a lot of different chassis and years, and coolant hose routing changed between them. Give us your VIN or pull the number off your old hose and we'll confirm before you order.
Is this the same as the Gates 691850?
It cross-references to it - same ID, same 90-degree bend, built to the same spec as the Detroit 23518315. Different manufacturer, same physical part. Check your old hose's leg lengths against it if you want to be sure before installing.
My hose has no readable number on it, how do I know if this is the right one?
Measure the ID (should be 1 inch) and the length of each leg off the bend, then compare to our listing. If it's close and the engine matches, it'll almost always work - but for a guarantee, give us the VIN and we'll look it up on our end.
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.