Ordering the wrong CAT radiator is one of the more expensive mistakes a workshop can make: cores are heavy, freight isn't cheap, and a machine sitting idle waiting for a return-and-reorder cycle costs more than the part itself. This guide walks through how Caterpillar radiators are identified across model ranges, the part numbers you're most likely to be chasing, and how to approach replacement without the guesswork.
Why CAT Radiator Part Numbers Get Confusing
Caterpillar has run several radiator designs across each model line as machines move through D, E, and GC series updates, and aftermarket suppliers often list the same core under half a dozen cross-reference numbers. It's a bit like trying to order a replacement part for a well-used family car that's had three facelifts; the badge on the front says the same thing, but the part underneath the bonnet has quietly changed two or three times.
That's why the serial number plate on your machine, not just the model name, is the real source of truth. Caterpillar's own service literature is built around machine serial number ranges for exactly this reason: two "320D" excavators built five years apart can call for different radiator part numbers depending on engine and cooling package.
Common Caterpillar Radiator Part Numbers by Model
- CAT 320D, 330D: One of the most widely cross-referenced radiators is part number 265-3624, also listed under 212042
- CAT 320D, 323D, 325D, 329D: Commonly seen as 265-3556, along with 326-3870 and 312-8340 — note that both a standard radiator core and a separate hydraulic radiator variant exist for this platform, so confirm which one you need
- CAT 320D, 320DL, 323D, 323DL: Several valid cross-references exist for the same core family, including 850924, 312-8341, 326-3956 and 360-9273
- CAT 336E: Commonly referenced as 450560
- Multiple D-series and C-series engines: Radiator cap 036-1865 shows up repeatedly as a shared component
Always cross-check any of these against your machine's serial plate or parts book before ordering, and if you're not sure which of several cross-reference numbers applies, reach out to our team for a fitment check.
If your model or generation isn't covered above, our full Caterpillar Parts collection and Radiators collection are searchable by part number, or you can call our team directly for a manual cross-check.
Aluminium or Copper? What Most Modern CAT Machines Run
Most Caterpillar excavators from the D-series onward ship with aluminium-core radiators as standard, chosen for their lighter weight and strong corrosion resistance across the long duty cycles typical of mining and civil construction work. Older C-series and B-series machines are more likely to run copper-brass units.
If you're deciding whether to replace like-for-like or upgrade an older CAT machine to an aluminium unit, our guide, Aluminium vs Copper Radiators for Heavy Equipment: Which Is Better?, walks through the trade-offs in detail, including a full side-by-side comparison.
A Hypothetical Example: Diagnosing a "CAT Radiator" That Wasn't the Problem
Consider a workshop that gets a call about a CAT 320D running hot on a demolition site. The obvious assumption is a failed radiator, and the team orders a replacement core on the spot. When it arrives and gets fitted, the machine still overheats.
The actual issue, on inspection, turns out to be a collapsed lower radiator hose restricting flow; the radiator itself was fine. A cooling system is a chain, not a single link. The main components involved are:
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The radiator core itself
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The water pump
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The fan and fan motor
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Hoses and clamps
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Coolant condition and mix
Ordering a new core without checking the rest of the chain is a bit like replacing a car's radiator because the heater isn't blowing hot; sometimes the fix is somewhere else in the loop entirely. Before you commit to a full radiator replacement, it's worth ruling out hoses, thermostat, fan drive and coolant condition first a cheaper fix that a lot of workshops skip past in the rush to order the "obvious" part.
Step-by-Step: Replacing a CAT Radiator
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Confirm the part number against your machine's serial plate, not just the model badge; see the section above
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Drain the coolant fully into a proper containment vessel before removing any lines
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Disconnect and inspect hoses and clamps; this is the right moment to replace worn caps and hoses rather than reusing them
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Remove the fan shroud and guarding as needed to clear the old core
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Unbolt and remove the old radiator, checking mounting brackets and isolators for wear
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Fit the new radiator, torque mounts to spec, and reconnect hoses with new clamps
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Refill with the correct coolant specification and bleed the system per your machine's service manual
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Run the machine under load and monitor temperature gauges through a full duty cycle before signing the job off
