The Cat 320D is probably the single most common excavator in the used fleets we supply parts for across Africa, the Middle East and Latin America — which means it is also the machine whose filter numbers get misquoted most often. Ask three sellers for "320D filters" and you will get three different lists, because the 320D was built in multiple serial runs that changed detail part numbers, and because some sellers are quoting you elements from other Cat engine classes entirely. This guide is the complete, source-checked list for the standard 320D and 320D L with the C6.4 ACERT engine, with the serial rules that stop you buying the wrong one.
1. The Complete Cat 320D Filter List (C6.4 Engine)
The table below is compiled from Cat's own 320D parts reference guide and the 320D parts manual (replacement-items section), cross-checked against aftermarket fitment lists in September 2026. For the standard 320D — and, where noted, the 320D L and 320D GC — this is the full service set:
| Service item | OEM part number | Notes |
|---|---|---|
| Engine oil filter | 1R-0739 | Most 320D/320D L/320D GC builds; older Cat numbers 1R-0658 and 1W-3300 appear on the same fitment lists |
| Fuel filter element | 1R-0751 | Fuel filter change item in Cat's 320D reference guide |
| Fuel/water separator element | 326-1644 | Supersedes the 1R-0770 element listed in the 320D parts manual |
| Air filter — outer (primary) | 131-8822 | Some listings supersede with 134-0685; shared with 320B–320E family |
| Air filter — inner (secondary) | 131-8821 | Always ordered as a pair with the outer element |
| Hydraulic tank return filter | 179-9806 | Also listed for the 323D/330D/336D family by sellers — confirm by serial |
| Pilot filter | 5I-8670 | Some manuals also list 126-1813 — serial-confirm |
| Case drain filter | 093-7521 | Fitted in the hydraulic case-drain line |
Two cautions before you order anything. First, the 320D GC shares the 1R-0739 / 1R-0751 / 326-1644 line with the standard 320D, but the later 320D2 and 320D2 GC run a different engine and different filter numbers — do not carry this list across to a D2. Second, the 1R-0751 fuel element and 326-1644 separator are not the 1R-0749 / 1R-0750 elements some listings try to sell for the 320D; those belong to the C10–C18 engine class. Our 1R-0750 and 1R-0749 product pages cover exactly which machines those fit.
2. The Numbers That Depend on Your Serial
Cat's own 320D parts reference guide splits the standard 320D by serial prefix. The mainstream prefixes list the elements in the table above — 1R-0739 oil filter, 1R-0751 fuel element, 326-1644 water separator — while MZD-prefix builds list the 1R-1807 oil filter with separate fuel and separator numbers (364-5287 and 438-5386 on the same guide). Nothing about this is guessable from the model name on the side of the machine, and that is the point:
- Photo the old element. The stamped number on the filter you are replacing settles more arguments than any model badge. If the stamping is worn, measure thread size and outer diameter in millimetres.
- Send the serial. The serial ties your machine to its exact build specification, which is how a supplier picks between 1R-0739 and 1R-1807 before quoting instead of after.
- Watch for supersessions, not mistakes. 326-1644 replacing 1R-0770, and 134-0685 appearing on listings alongside 131-8822, are normal number changes across Cat's production — they are not signs of a wrong part. A real red flag is a seller quoting a number that belongs to a different engine family (like 1R-0750 on a C6.4 machine).
The air side deserves one extra note: 320D air housings changed across builds, and some later 320-class machines run radial-seal elements that fit only their own housing. If the label on your housing names a filter family you do not recognise, send a photo of the housing label together with the old element number — that combination is enough to confirm the right pair.
3. How to Order 320D Filters Without Paying Twice
The economics of this machine are simple: its filters ship flat and light, so the freight cost of buying the full service set together is barely more than buying one element — while a wrong element costs you double freight plus the downtime of discovering it on site. Buyers who order Cat 320D filters from us tend to follow the same routine:
- Order the set, not the single. Oil, fuel, separator, two air elements and the return filter cover one full service interval, and bundling removes the "which one is due next" phone call.
- Price against the band, not the cheapest listing. Quality aftermarket elements for this machine typically run 30–60% below OEM list — and a price far under that band usually means thinner media. The authenticity checks in our fake-filter guide and OEM parts guide apply to every element in the list above.
- Get the confirmation in writing. A one-line "confirmed for serial XYZ" before payment is free; a teardown to fit a wrong filter is not.
If you are buying filters for a 320D you do not have in the workshop yet — the usual situation when a container of used excavators is still on the water — collect the serials and old-part numbers at the pre-shipment inspection. Send the filter list with the machine order and the service set can ride in the same container. Need the full picture on Cat filtration across models? Our Caterpillar engine parts guide covers the C7/C15/C18 side of the family, and the filters catalogue carries the Cat and Komatsu model-specific ranges.
FAQ
Q: What engine oil filter does a Cat 320D take?
A: Most Cat 320D and 320D L builds (C6.4 engine) list the 1R-0739 engine oil filter — Cat's own 320D parts reference guide confirms it for the standard 320D, the 320D L and the 320D GC. MZD-prefix 320D builds list the 1R-1807 element instead, so confirm with your old filter's number and machine serial. Aftermarket crosses for 1R-0739 include Baldwin B7600, Fleetguard LF667 and Donaldson P554004.
Q: Does the 1R-0750 or 1R-0749 fuel filter fit a Cat 320D?
A: No — the 1R-0749 and 1R-0750 elements belong to the C10–C18 engine class (the 1R-0749 is also listed for 330D/336D machines), not the 320D's C6.4 engine. Cat's 320D parts reference guide lists the 1R-0751 fuel filter element and the 326-1644 fuel/water separator element for the standard 320D. Ordering 320D fuel parts by model name alone is how the wrong element arrives.
Q: Which air filter elements fit a Cat 320D?
A: The 320D parts manual lists two elements: the 131-8822 outer/primary element and the 131-8821 inner/secondary element, a set shared across the 320B–320E family of excavators; some aftermarket listings supersede the 131-8822 with 134-0685. Air housings changed across builds, so confirm the element family against the label on the housing or old element.
Q: How do I order Cat 320D filters from CN Machinery?
A: Message us on WhatsApp or email sales@cn-machinery.com with your machine serial and the numbers printed on the old elements — photos help. We confirm every element against your machine before dispatch. Stock filter lines ship in 3–7 days, FOB Shanghai or CIF to your port, and quality aftermarket elements typically run 30–60% below OEM list.
Need Filters for a Cat 320D?
Send your machine serial and a photo of the old elements — we confirm the right part numbers and quote within 24 hours.
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