Genuine Cummins Onan Green Label spin-on oil filter with bypass valve for HDKAG (Spec C–G) and HQDPB (Spec A) Quiet Diesel generators. Fleetguard LF3536 direct substitute. Spec letter verification required — not all HDKAG and HQDPB specs use this filter. 90-day limited warranty.
The Cummins Onan 185-5835 is the OEM-specified spin-on oil filter for the HDKAG older Quiet Diesel series (Spec C and later) and the HQDPB HQD Series (Spec A). It is a Green Label filter featuring an integrated bypass valve — a critical component that allows oil to flow during cold starts or if the filter element becomes restricted.
Aftermarket "will-fit" filters frequently lack bypass valves. As these filters trap debris, oil pressure starvation can occur, leading to elevated oil pressure, failed gaskets, and engine damage. For diesel generators, which operate under higher oil pressure and thermal stress than gasoline units, using a bypass-valve filter is especially important.
Spec letter verification is required before ordering. Not all HDKAG and HQDPB spec letters use this filter — see the fitment table and warning section below.
Integrated bypass valve at 86 kPa prevents oil starvation during cold starts and if the filter becomes restricted — non-bypass filters cause pressure buildup, failed gaskets, and engine damage
95% filtration efficiency at 30 microns — captures metal particles, carbon deposits, and contaminants that circulate through the diesel engine during operation
Fleetguard LF3536 is a direct Cummins OEM substitute with identical specifications — you may receive either part number
Tested and designed specifically for Cummins Onan Quiet Diesel RV generators — meets OEM specifications for HDKAG and HQDPB applications
Per the Cummins Onan Green Label Parts Reference Guide, this filter does not apply to every spec letter within the HDKAG and HQDPB families: • HDKAG Spec A–B: Uses a different filter (185-6623) — not this part • HQDPB Spec B: Uses a different filter (333-0802) — not this part Always verify your generator's spec letter from the identification nameplate before ordering. The spec letter appears after the model designation on the generator's data plate.
Fleetguard is Cummins' own filtration brand. The LF3536 is not a third-party aftermarket substitute — it is an OEM Cummins product with identical specifications to the 185-5835. If you receive a Fleetguard LF3536 in place of the Onan-labeled 185-5835, this is a genuine direct substitute and will not affect your generator's performance or warranty standing.
Backed by a 90-day limited manufacturer's warranty against defects in materials and workmanship. Cummins Power Generation warrants only the quality and integrity of Green Label Parts. Damage caused by the use of non-Green Label or non-bypass oil filters is not covered under the Cummins Onan limited warranty.