Motor Grader Fuel Tank Cap – Neck, Vent and Seal Identification
A motor grader fuel tank cap must seal the filler neck while allowing the fuel system to vent as designed. Caps with a similar diameter may differ in threads, bayonet lugs, locks, vents and gasket depth.
Ordering basis: Measure the filler neck and confirm cap retention, venting and gasket design before ordering.
Cap and filler-neck checks
Measure neck outside and inside diameters.
Identify threaded, bayonet or locking retention.
Check lug count, pitch, cap depth and stop position.
Inspect the gasket seat and determine whether the cap is vented.
Symptoms that are not always a bad cap
Fuel starvation, tank vacuum or leakage can also result from a blocked vent line, damaged filler neck, deformed gasket seat or contamination. Inspect the neck and vent path before replacing the cap.
Fit and leak check
Clean the filler area so dirt cannot enter the tank. Fit the correct gasket, close the cap through its full travel and confirm that it locks or stops securely. Check for leakage and abnormal tank pressure during operation.
Product record
| Component | Fuel tank filler cap |
| Part number | Not shown — verify from the original component or parts catalogue |
| Fitment rule | filler-neck diameter, locking design, venting method, seal profile and machine application |
Related product reference
Review the engine-system component identification example for another component-level identification workflow. The linked product is a reference only and does not establish interchangeability.
FAQ
Can a cap be selected by diameter only?
No. Thread or lug design, depth, gasket and venting method must also match.
Should a vented cap be replaced with a sealed cap?
Only if the machine uses a separate verified vent system and the parts catalogue specifies it.
Why is fuel leaking around a new cap?
The neck may be bent, the gasket may be wrong or the cap may not reach the correct locking position.
Compatibility note: Verify the filler neck and fuel-system vent design before ordering.
