What 396.5(a) means in plain language
This regulation targets commercial motor vehicles that are being operated while an oil or grease leak is present — whether that leak originates from the engine, the transmission, or any other drivetrain or mechanical component on the vehicle.
The key word is operating. The violation isn't about having a leaking truck parked at a terminal. It's about putting that vehicle in motion — or keeping it in motion — when a leak is already visible or detectable. An inspector who spots fresh oil drips under your engine, a wet transmission housing, or grease seeping from a wheel-end component has grounds to write this citation.
Leaks matter beyond the paperwork. An uncontrolled oil leak creates a fire risk near hot engine surfaces, degrades braking performance if fluid contacts brake components, and signals that a maintenance issue has been ignored long enough to show up on the pavement.
What our enforcement data actually shows
Across our database of 13 million+ inspections, 396.5(a) has generated 4,930 all-time citations, placing it at #342 out of 3,036 FMCSR codes by citation volume. That puts it in roughly the top 11% of all tracked codes — not a rare find.
The out-of-service picture is more nuanced. Of those 4,930 citations, 1,329 resulted in a vehicle being placed out of service, for a 27.0% OOS rate. That's worth pausing on: 396.5(a) is technically listed as not OOS-eligible under the standard criteria, yet our records show inspectors placed vehicles out of service in more than one in four encounters. How? When an oil leak is severe enough, inspectors can cite a companion code — often 396.7 (unsafe operations) — that does carry OOS authority. The co-occurrence patterns in our data confirm exactly that. The net result is that 27.0% of 396.5(a) inspections ended with the truck parked. For context, the all-FMCSR average OOS rate across all codes is 31.4%, so this code runs about 4.4 percentage points below average — but the gap is not a reason for comfort given the volume.
Recent activity has quieted significantly. Our inspection records show only 3 citations in the last 12 months and 2 in the last 90 days. That low recent frequency doesn't mean enforcement pressure has vanished; it means the inspectors who do flag it are still flagging it, and the historical 27.0% OOS conversion rate hasn't changed.
Who gets cited most
Looking at the last 180 days, the only state with recorded citations in our database is Texas, with 2 citations — and 1 of those resulted in an OOS placement, a 50.0% OOS rate for that window. Texas is a high-inspection-volume state generally, so its presence here is consistent with overall enforcement patterns.
On the carrier side, our data shows fleets such as United Parcel Service Inc (USDOT 21800) with 31 all-time citations and CRST Expedited Inc (USDOT 53773) with 17 citations leading the all-time count. These are high-mileage, large-fleet operations with enormous inspection exposure, and their appearance at the top of a citation list reflects volume of operations as much as anything else.
On the equipment side, FRHT-badged vehicles account for 1,505 all-time citations — the single largest make in our records for this code — followed by UTIL at 572 and KW at 465. If you're running a Freightliner-family truck, the data suggests your platform shows up disproportionately often in these inspections.
How severe is this compared to similar codes
Within the Vehicle Maintenance category, 396.5(a)'s 4,930 citations are a small number compared to the heavyweights. Consider 393.9(a) — Inoperable required lamps, which has accumulated 660,737 citations in our database — roughly 134 times the volume of 396.5(a). Its OOS rate sits at 15.4%, well below 396.5(a)'s 27.0%, meaning that when inspectors do find an oil/grease leak they're more likely to take enforcement action than when they find a bad lamp.
Look at 396.3(a)(1) — Inspection/repair/maintenance (general), which carries 236,919 citations and a 45.3% OOS rate. That's the broader maintenance-failure umbrella, and its higher OOS rate reflects how aggressively inspectors use it. When a 396.5(a) citation appears alongside a 396.3(a)(1) citation in our co-occurrence records, the combination is far more likely to end with a truck parked.
396.17(c) — No proof of periodic inspection shows 198,331 citations but a 0.0% OOS rate. Pure paperwork violation, no OOS risk. By contrast, 396.5(a)'s real-world 27.0% OOS conversion rate is a reminder that mechanical condition violations carry teeth that documentation violations do not.
How to avoid it
The co-occurrence data in our records is a direct map of what inspectors find on the same truck at the same inspection when 396.5(a) is written. Use that map to structure your pre-trip:
- Walk the undercarriage slowly. A visual scan of the ground under the engine, transmission, and drive axles before you move the truck takes under two minutes. Fresh oil or grease on the pavement is the first clue.
- Check brake components for contamination. Our data shows 393.47E (slack adjuster defective) and 393.48A (inoperative/defective brakes) co-occurring with 396.5(a). Leaked oil that migrates to brake shoes or slack adjusters creates a compounding violation scenario — one leak turns into three or four write-ups.
- Inspect steering linkage and coupling hardware. 393.53B (steering system components worn) and 393.55D2 (coupling device defective) also appear in the co-occurrence pattern. Grease purging from worn steering joints or fifth-wheel components is a direct pathway to a 396.5(a) citation.
- Verify lights and emergency equipment before departure. 393.11 (lighting devices/reflectors) and both 393.95A and 393.95F (fire extinguisher and warning devices) show up in the same inspections. An inspector writing one violation will walk the whole truck — a clean vehicle limits exposure across all categories.
- Freightliner and Kenworth operators: pay extra attention to engine seals and transmission gaskets. FRHT accounts for 1,505 citations and KW for 465 in our all-time records. If you're running either platform, add a specific check of valve cover gaskets, oil pan seals, and transmission output shaft seals to your standard pre-trip routine.
- Don't dismiss a minor seep. Inspectors don't require a puddle. A visible wet film on a component surface is enough. Address seeps at the terminal before dispatch, not at a scale or inspection station.