Factory specifications, fluid capacities, torque values, EPA fuel economy and the federal safety record for the 1991 P-Series MD Bus Chassis.
The 1991 Chevrolet P-Series MD Bus Chassis served as a purpose-built medium-duty platform designed to underpin a wide range of commercial and shuttle bodies, powered by a robust yet straightforward engine lineup that included both gasoline and diesel options. With a compact footprint yet capable of supporting substantial payloads, this chassis became a staple for operators needing durability without excess complexity—its 5W-30 API-rated engine oil requirement underscoring a design balanced for both cold starts and sustained heavy use. Remarkably, this model year stands out in the P-Series timeline for its near-flawless reliability record, with just a single owner-reported complaint—isolated to the powertrain—and no recalls, signaling a rare moment of refinement in a line often plagued by more frequent issues. For researchers, it represents a pragmatic benchmark: a workhorse that, in 1991, delivered the rare combination of simplicity and dependability that fleet managers prized.
Fluid capacities, tune-up values and fuel economy at a glance.
Capacities, torques and tune-up values from the factory service manual.
This engine holds 4 qt of 5W-30 API engine oil, 80W-90 · GL-5 in the differential, DOT 3 brake fluid.
| Brake Fluid | DOT 3 |
| Differential Gear Oil | 80W-90 · GL-5 |
| Differential Gear Oil Capacity | 14.0 qt |
| Differential Gear Oil | 80W-90 · GL-5 |
| Differential Gear Oil Capacity | 5.5 qt |
| Engine Coolant | ETHYLENE GLYCOL |
| Engine Oil | 5W-30 · API |
| Engine Oil Capacity | 4 qt |
Owner-reported issues, recalls, investigations and service bulletins on record with NHTSA — an unfiltered look at what owners actually experience.
Owner complaints about the 1991 Chevrolet P-Series MD Bus Chassis dominate in one area — the power train, 1 of 1 reports (100%), well ahead of the next concern. NHTSA has issued no recalls for this vehicle, so these are owner-reported concerns only. 0 of the reports describe a crash and 0 a fire — a small share of the total, but worth weighing against the power train pattern above. These are tallies of what owners actually reported to the federal government, not an editorial score — and higher-selling models naturally rack up more reports.
All 1 complaints on record, top 1 components.
Source: NHTSA Office of Defects Investigation complaint database.
No recall campaigns on record with NHTSA for this vehicle as of the last data refresh.
Showing 5 of 6 bulletins on record with NHTSA.
| Bulletin | Date | Component | Summary |
|---|---|---|---|
| 000604002 | 2000-01-01 | Engine And Engine Cooling | SUBJECT REGARDING A HARD, NO START OR EXCESSIVE GRAY OR WHITE SMOKE CONDITION ON START UP… |
| 98831110 | 1998-02-01 | Engine And Engine Cooling | VEHICLES WITH 6.0L AND 7.0L ENGINES (VINS P, M - RPOS LS0, LR0) MAY EXHIBIT ENGINE… |
| 376105 | 1995-02-01 | Engine And Engine Cooling | COLD ENGINE KNOCK. *TW |
| 376602A | 1995-01-01 | Engine And Engine Cooling | NEW CAST IRON EXHAUST MANIFOLD AND STAINLESS STEEL GASKET TO CORRECT ENGINE NOISE… |
| 476149 | 1994-12-01 | Unknown Or Other | OIL PRESSURE GAUGE READING CONCERNS. *TW |
The most common OBD-II codes for this vehicle's emissions system. These are standardized SAE J2012 definitions, not vehicle-specific fault reports.
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Cross-vehicle references for the kinds of data on this page.
4 qt of 5W-30 API, per the factory manual.
NHTSA lists 0 recall campaign(s) for this model year. Check your specific vehicle by VIN.