Oil Pan Seal Fits Most Military HUMVEE 6.5L Diesel Engine (Later A2/Rev Models)
National Stock Number (NSN): 5330-01-378-8572
Manufacturer / GM Part Number: 23502587 (or GEP23502587). AM General Part Number: 5743235
IMPORTANT!
For the 6.2L Diesel Engine (Earliest A0/A1 Models)
If you are working on an early-generation 6.2L Humvee, the oil pan profile requires a different thickness, making this 6.5L part incompatible.
Summary Checklist for a 6.5L Fitment:
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Standard 6.5L (Naturally Aspirated & Turbo): Yes, it fits.
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6.5L with One-Piece Rear Main Seal: Yes, it fits.
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Early 6.5L with Two-Piece Rear Main Seal: No.
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Upgraded 6.5L P400 Bedplate Engine: No
Tech Tip: Military mechanics and Technical Manuals notes mention that on later 6.5L engines, only this rear U-shaped seal is used, while the left and right flat edges of the oil pan are sealed directly with Loctite 5900 RTV sealant rather than traditional cork/rubber side gaskets to permanently stop drops and leaks.
Stop messy oil leaks and protect your powertrain with this premium-grade rear oil pan seal. Specifically engineered to deliver a perfect, leak-free seal, this heavy-duty component withstands intense engine temperatures, vibration, and rigorous off-road conditions.
Designed for later-generation vehicles equipped with the standard 6.5-liter naturally aspirated or turbocharged engine block configuration, it provides a precise factory-spec fit. This U-shaped rear seal prevents oil from seeping out of the main pan mating surface, ensuring critical engine lubrication levels remain secure over thousands of miles.
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National Stock Number (NSN): 5330-01-378-8572
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General Motors / Manufacturer Part Number: 23502587 (also designated as GEP23502587)
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AM General Part Number: 5743235
Fitment Note: This seal is strictly designed for 6.5L power plants with a one-piece rear main seal setup. It is incompatible with older 6.2L diesel engine blocks (A0/A1 configurations), early 6.5L variations utilizing a two-piece rear main seal, or upgraded P400 bedplate engines.
Compatible Vehicle Models
This oil pan seal is compatible with later A2-series and Revised (Rev) military fleet variants, including the following model numbers:
M1025A2, M1035A2, M1043A2, M1045A2, M1097A2, M1113, M1114, M1123, M1151, M1152, M1165, M1167
Replacement Interval Guide
Under normal operation, an oil pan seal is classified as a "replace-on-condition" item rather than a scheduled preventative maintenance part. It should be replaced immediately if you observe active dripping, dampness around the oil pan rails, or a drop in engine oil levels caused by a compromised rear seam.
However, because accessing the oil pan requires significant labor, it is standard mechanical consensus to always replace this seal whenever the oil pan is removed for other maintenance tasks or engine overhauls.
