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International Hx515 Diesel Exhaust Fluid (DEF) Filler Caps

International Hx515 Diesel exhaust fluid (def) filler caps

Starting at $20.95, AutoBuffy stocks 1 Diesel Exhaust Fluid (DEF) filler caps from Gates for the International Hx515. The DEF filler cap seals the separate blue-capped tank that feeds your SCR emissions system. A cracked, missing, or poorly sealing cap lets moisture and contaminants into the DEF tank, which can crystallize injectors, trigger fault codes, and derate engine power.

Signs your International Hx515 needs a new DEF filler cap

  • DEF warning light or 'Check Emissions System' message appears on the dashboard even after the tank is full
  • Visible white crystalline residue or dried DEF crust around the filler neck, indicating a leaking or venting cap
  • Smell of ammonia near the DEF tank area, caused by unsealed fluid evaporating
  • DEF level drops faster than expected between fill-ups with no visible puddle underneath the vehicle
  • Cap is cracked, broken, or the blue plastic has become brittle and no longer clicks or locks into place
  • OBD-II scanner shows DEF quality or contamination fault codes, which can result from water or dirt entering through a bad cap seal

Which DEF filler cap should you buy for your International Hx515?

The most important factor is fitment: DEF filler caps use a specific thread pitch and neck diameter that differs from the diesel fuel cap, and the two are intentionally incompatible to prevent misfueling. Beyond fitment, consider whether you want an OE-equivalent replacement or a locking cap for fleet or job-site use where tampering or accidental misfueling is a concern.

OEM Replacement Cap
Best for
Restoring the factory seal quickly and reliably
What you get
Exact thread pitch, torque-to-click mechanism, and integrated gasket matching the original spec for your International Hx515
OE-Equivalent Aftermarket Cap
Best for
Budget-conscious owners who still want a proper seal
What you get
Compatible fitment at a lower price point; quality varies by brand so stick to Gates
Locking DEF Cap
Best for
Fleet vehicles, work trucks, or high-theft environments
What you get
Keyed or tool-required removal to prevent accidental diesel misfueling and unauthorized access to the DEF tank
Cap with Integrated Strainer/Filter
Best for
Vehicles operating in dusty or dirty environments
What you get
Built-in mesh screen that filters debris as you pour, adding a layer of protection against DEF contamination

Diesel exhaust fluid (def) filler caps brands we stock for your International Hx515

Gates
1 option · from $20.95

Replacing a DEF filler cap on a International Hx515

Easy⏱ Under 5 minutesNitrile gloves (DEF is a mild irritant)Clean lint-free ragMild soap and water or DEF-safe cleaner for neck cleaning

Replacing a DEF filler cap is a simple hand-tight swap requiring no tools. Remove the old cap by turning it counterclockwise, wipe the filler neck clean of any crystallized residue with a damp rag, then thread the new cap on clockwise until it clicks or seats firmly. Clear any related fault codes with a scan tool after installation and confirm the DEF level is adequate before returning the vehicle to service.

Frequently asked questions

How much does it cost to replace DEF filler caps on a International Hx515?
A replacement DEF filler cap for a International Hx515 starts at $20.95 for an aftermarket unit. OEM caps and locking versions typically cost more. Because this is a straightforward cap swap requiring no special tools or labor time, the part price is essentially the total cost of the repair.
Can I drive my International Hx515 with a missing or broken DEF filler cap?
You can drive short distances, but it is not advisable. Without a proper seal, the DEF tank is open to moisture, dust, and contamination. Contaminated DEF can damage the SCR injector and catalyst. Most diesel engines will also begin a countdown derate cycle once a DEF-related fault is logged, eventually limiting vehicle speed.
Will a bad DEF cap cause my International Hx515 to derate or go into limp mode?
Yes, indirectly. A failed cap that allows contamination can trigger DEF quality fault codes. Once the engine control module detects a DEF system fault, it initiates a torque or speed derate as required by EPA regulations. Replacing the cap and refilling with fresh, certified DEF is the first step to clearing the condition.
Is the DEF filler cap the same as the diesel fuel cap on a International Hx515?
No. DEF filler caps and diesel fuel caps are intentionally different sizes and thread patterns. The DEF filler neck is smaller and color-coded blue specifically to prevent putting diesel in the DEF tank or DEF in the fuel tank. Never force a fuel cap onto the DEF neck or vice versa.
How do I know if my International Hx515's DEF cap seal is bad vs. a larger DEF system problem?
Start by inspecting the cap itself: look for cracks, a damaged rubber gasket, or a cap that does not click and seat firmly. If the cap looks intact but you still have fault codes, the issue may be with the DEF quality sensor, level sensor, or SCR injector. A cap is the lowest-cost first check.
How often should I replace the DEF filler cap on my International Hx515?
There is no fixed replacement interval. DEF caps are typically replaced on condition — when cracked, when the gasket hardens or deforms, or when the locking mechanism fails. Inspect the cap and its rubber seal each time you refill DEF. Cold climates can accelerate gasket brittleness, so inspect more frequently in harsh winters.

Shop diesel exhaust fluid (def) filler caps by year for the International Hx515

2019

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