Cat 320 Air Filter Numbers by Generation

One Badge, Three Air Cleaners

The 320 is the most common Cat excavator in the world, and it has been three different machines under one name. Air filtration follows the engine and the air cleaner housing, not the decal, so "air filter for a 320" has three answers that do not trade.

The first is the 320B, 320C and 320D family. Its primary element is 131-8822, a round radial-seal element, with 131-8821 as the inner safety element behind it. Cat's parts listings run that pair across the 320B, 320B L, 320C, 320D, 320D GC, 320D L, 320D RR, 323D and 320E machines, and the same number appears for the 320F L — practical evidence of how long this air cleaner stayed in production.

The second is the 320D2 generation: 320D2, 320D2 GC, 320D2 L, 320E, 320E L, 320F L and the 323D2 and 323E machines. Here the primary element is 528-7222, a round element in the circular air cleaner housing, quoted by Cat at 8.457 in (214.8 mm) across and 16.315 in (414.4 mm) deep. Its internal safety element is a separate number, so it is ordered separately — the outer number alone is half an order.

The third is the current machine. The 320, 320 GC, 320 GX, 323, 323 GC, 323 GX, 324, 325, 326, 326 GC, 333 GC and 335 run the non-round primary 479-8989 in UHE media, with the flat secondary 479-8991 behind it. Cat's 320 / 320 GC / 323 parts reference guide lists the pair against the ZBN, DKJ, YBL and RAZ serial prefixes, and the companion guide covering the HEX, MYK, KTN and LKS prefixes lists the same two numbers.

Which Number for Which Machine

Generation	Primary element	Secondary element	Shape and size
320B / 320C / 320D / 320D L / 320D GC	131-8822	131-8821	Round, radial seal, ~237 mm OD × 130.9 mm ID × 330.2 mm
320D2 / 320D2 GC / 320D2 L / 320E / 320F L	528-7222	Separate safety element — confirm by serial prefix	Round, circular housing, Cat published 214.8 mm × 414.4 mm
Next Gen 320 / 320 GC / 320 GX / 323 / 323 GC / 324 / 325 / 326 / 326 GC / 333 GC / 335	479-8989	479-8991	Non-round, UHE media, Cat published 203 × 297 × 389 mm
D4 / D5 dozers, M317 to M323 wheeled excavators, 120 grader, FM528 forestry	479-8989	479-8991	Same non-round pair as the current excavators

One line in that table is deliberately incomplete. Cat publishes a safety element for the 320D2 family, but the number that reaches us through supplier catalogues varies with the housing fitted, so we ask for the serial prefix and the old element instead of printing a guess. A blank cell in a table costs a buyer one email; a wrong number costs a week.

How to Confirm Which One You Have

Four checks, none of them longer than a minute, and together they settle the question completely.

Read the serial prefix. The PIN plate carries it, and Cat's own guides are organised by it. ZBN, DKJ, YBL and RAZ are the current 320, 320 GC and 323 generation; HEX, MYK, KTN and LKS appear on current 320 and 320 GC machines in the companion guide. If the prefix is one of those, you are in the 479-8989 / 479-8991 pair and the earlier numbers are irrelevant to you.

Look at the shape of the element. A round element that seats on a radial seal is 131-8822 or 528-7222. An oval, panel-style element with plastic end caps is 479-8989. This is the check that survives a machine that has been rebuilt, re-badged or assembled from two donors, which is exactly the machine that arrives at a parts counter with all three numbers quoted for it.

Measure. The three elements are far enough apart that a tape measure is decisive: about 237 mm across and 330 mm long is the 320D element, roughly 215 mm across and 414 mm long is the 528-7222, and approximately 203 mm by 297 mm by 389 mm is the 479-8989. On the 320D2 machines the difference between a 237 mm round element and a 215 mm round element is the difference between a filter that seats and one that leaks dust straight into the intake.

Check whether there is a secondary element. On the current 320 pair, a flat element sits behind the primary and it is 479-8991. Every generation on this page is a two-element system, and the second element is what keeps dust out of the engine while the primary is in your hand.

The Sizes We Publish, and Why Some Are Ranges

Element	Cat published / verified figures	Independent catalogue figures
131-8822	Primary radial seal, cellulose, ISO 5011 efficiency quoted at 99.9%	OD 237 mm, ID 130.9 mm, length 330.2 mm (two independent specification sheets agree)
131-8821	Secondary / safety element, radial seal, standard efficiency	OD 133.4 mm, ID 94.5 mm, length 323.1 mm; one source reads 132 × 94 × 323 mm
528-7222	Primary, round, standard-efficiency media, 8.457 in (214.8 mm) × 16.315 in (414.4 mm) overall	211–215 mm OD × 398–414 mm long, inner diameter 117–137 mm depending on source
479-8989	Primary, non-round, UHE media, plastic end caps: 7.992 in (203 mm) × 11.693 in (297 mm) × 15.315 in (389 mm)	200–203 × 295–297 × 388–392 mm, 2.19–2.2 kg across three catalogues
479-8991	Secondary, non-round, standard media, polyurethane end: 6.811 in (173 mm) × 2.559 in (65 mm) × 14.055 in (357 mm)	Width and depth agree; at least one supplier catalogue quotes a longer 385 mm element and is treated as an outlier

The pattern in the right-hand column is worth understanding rather than distrusting. Independent catalogues measure the element in front of them, and a supplier who copies an old measurement into a new listing leaves the number slightly out. Where Cat and the independents agree within a couple of millimetres — which is the case for the current non-round pair — a tape measure on your old element will match either figure. Where they disagree by more, we print the range and confirm against your part.

Cross References by Generation

Cross numbers are leads for a quotation, not fitment guarantees, and they are only as good as the number of independent sources behind them:

Cat number	Cross references we publish	What else circulates
131-8822	Donaldson P536457, WIX 46701, Fleetguard AF25589, Baldwin RS3736	Cat 134-0685 is the UHE upgrade number for the same position, not a substitute for every machine
131-8821	Fleetguard AF25624, Baldwin RS3737 (both appear against the 131-8822 inner in supplier catalogues)	Treat as leads — confirm against the old element
528-7222	WIX WA11720 (outer), paired in WIX's own catalogue with WA11721 as the inner	Some suppliers group 520-6407 with 528-7222; we do not present that as a substitution
479-8989	SA160066 (indexed as HIFI in some catalogue books, Sakura in others), SF-FILTER SL82517, WIX WA11217	Numbers that appear in a single listing are treated as unverified
479-8991	SA160067 (HIFI and Sakura books), WIX WA11220	One Fleetguard number circulates on single supplier pages and is wrong for this element — see below

The Fleetguard case is worth naming because it is the expensive kind of error. A copied supplier listing groups a Fleetguard number with 479-8991. Fleetguard's own catalogue data places that number on a different element altogether: a panel filter of roughly 175 × 223 mm sold for AGCO, Cummins and Doosan applications. A buyer assembling a filter list from copied pages orders it for a 320, receives something that fits nothing, and loses the week either way. The cross reference guide sets out the three-step check we use before printing any of these numbers.

The Three Mistakes in Air Filter Orders

Ordering by badge. "Cat 320 air filter" is the single most expensive search phrase on this page, because three current Cat numbers answer it. The prefix, the housing shape and the old element are the only three things that settle it.

Trusting a cross number that appears once. A number copied from one supplier page onto a website becomes "verified" after three copies, without anyone ever measuring an element. We label single-source numbers as leads on the product pages for exactly that reason.

Replacing half a pair. Every generation on this page uses a primary plus a secondary. The primary catches the dust; the secondary protects the engine while the primary is out of the housing and if the primary ever splits. Replacing one and leaving the other leaves the worn half in the machine, which is the machine that comes back with the same complaint a quarter later.

What We Do Not Publish

No air filter change intervals: Caterpillar sets servicing per machine group, serial range and duty cycle, and a 320 GC on a demolition site loads its air cleaner several times faster than one on general earthworks, so one number printed here would be wrong for most readers. The restriction indicator and the Operation and Maintenance Manual are the honest sources. No fixed prices: media grade, quantity and freight set the number. And no fitment guarantee built on a cross reference — the tables above separate what several sources agree on from what one supplier printed.

What we do instead is the free part. Send the serial prefix from the PIN plate and a photo of the old element next to a tape measure, and we come back with the primary, the secondary, the grade and the price for your machine, and ship in 3–7 days from Shanghai — FOB or CIF to your port.

FAQ

Q: What air filter does a Cat 320D take?
A: A Cat 320D takes the round radial-seal primary element 131-8822 with 131-8821 as the inner safety element behind it. Cat's parts listings put 131-8822 across the 320B, 320C, 320D, 320D L, 320D GC, 320D RR, 323D and 320E family, and the same element appears in the 320F L and 323D listings. Independent specification sheets quote it at about 237 mm outside diameter, 130.9 mm inside diameter and 330.2 mm long, crossing Donaldson P536457 and WIX 46701. If your machine is a 320D2 or later, it takes a different element altogether.

Q: Why does my 320 need a different filter than my neighbour's 320?
A: Because Caterpillar has built three quite different air cleaners under the 320 badge. The 320B to 320D family uses the round 131-8822 with 131-8821 behind it. The 320D2, 320D2 GC, 320D2 L, 320E, 320F L and 323E generation uses the round 528-7222 primary in the circular housing. The current 320, 320 GC, 320 GX, 323, 323 GC, 324, 325, 326, 326 GC, 333 GC and 335 uses the non-round 479-8989 with 479-8991 alongside it. None of the three fits another's housing, so the badge on the panel settles nothing.

Q: How do I confirm which Cat 320 air filter I need without a parts book?
A: Four checks, in this order. Read the serial prefix off the PIN plate — ZBN, DKJ, YBL and RAZ are the current 320, 320 GC and 323 generation, and HEX, MYK, KTN and LKS also appear on the current 320 and 320 GC in Cat's own guides. Open the air cleaner and look at the shape: a round element on a radial seal is 131-8822 or 528-7222, an oval panel-style element with plastic ends is 479-8989. Then measure the old element — about 237 mm across and 330 mm long is the 320D element, about 215 mm across and 414 mm long is the 528-7222, and roughly 203 mm by 297 mm by 389 mm is the 479-8989. Finally, check whether a flat secondary element sits behind the primary; on the current 320 pair it is 479-8991.

Q: Can I substitute a cross reference number for the Cat air filter?
A: Only when the number can be confirmed in more than one independent catalogue, and only after checking the dimensions. For the 320 family we publish the numbers that appear in several sources: Donaldson P536457, WIX 46701, Fleetguard AF25589 and Baldwin RS3736 against 131-8822; HIFI SA160066, SF-FILTER SL82517 and WIX WA11217 against 479-8989; HIFI SA160067 and WIX WA11220 against 479-8991. Numbers that appear on a single supplier page we treat as leads, not substitutes — one widely copied listing pairs a Fleetguard number with 479-8991 that Fleetguard's own data places on an unrelated panel element.