How to Buy a Used CAT Excavator: 20 Questions Answered
Used CAT excavator buying guide
How to Buy a Used CAT Excavator: 20 Questions Answered
Twenty direct decision blocks for buyers comparing 6-90 tonne CAT excavators by operating weight, job application, generation, hours, engine, hydraulics, undercarriage, attachment, shipping and landed cost.
| Excavator class | Screening operating weight | Representative CAT models | Best-fit applications |
|---|---|---|---|
| Compact / mini | About 6-10 t | 306, 307, 308, 310 | Utilities, landscaping, drainage, confined sites |
| Small construction | About 11-18 t | 311, 312, 313, 315, 317, 318 | Urban construction, pipe, foundations, road work |
| General construction | About 20-25 t | 320, 320 GC, 323, 325 | General excavation, trenching, truck loading |
| Production | About 29-40 t | 329, 330, 336, 340 | Mass earthmoving, deep foundations, quarry support |
| Heavy production | About 45-55 t | 345, 349, 350, 352 | Rock excavation, large truck loading, major cuts |
| Quarry / mining | About 70-90+ t | 374, 390, 395 | Quarry faces, mining support, continuous production |
These are buying-screen ranges, not universal model weights. Exact operating weight changes with generation, boom, stick, bucket, counterweight, track shoes and guarding; verify the serial-specific specification before transport or lifting decisions.
1. What operating-weight class of used CAT excavator should I buy?
Choose the smallest CAT excavator that safely meets the required digging depth, reach, lift and hourly production. Use operating weight as the first screen: about 6-10 tonnes for utilities and tight sites, 11-18 tonnes for urban construction, 20-25 tonnes for general contracting, 29-40 tonnes for mass earthmoving, 45-55 tonnes for heavy production, and roughly 70-90 tonnes for quarry or mining work. A heavier machine adds stability and bucket capacity but also raises fuel, transport and undercarriage cost. Recommendation: define the hardest regular task and transport limit first, then choose the lowest weight class that completes it with reserve.
2. Should I choose a CAT 306/308, 312 or 315 for smaller jobs?
Choose a 306/308 class for access and transport, a 312 class for balanced utility work, and a 315 class when lifting and production matter more. The 6-8 tonne machines fit narrow roads, landscaping, farm drainage and municipal repairs; 12-14 tonne machines add reach and stability without the footprint of a 20-tonner; 15-17 tonne machines better handle deeper trenches, larger pipe and heavier attachments. The trade-off is higher transport weight, ground pressure and fuel use at each step. Recommendation: buy the 306/308 for confined work, the 312 for mixed utility projects, and the 315 for regular lifting or deeper excavation.
3. Should I buy a used CAT 320D, 320 GC or 323?
Choose a 320D for proven used-market value, a 320 GC for moderate-duty efficiency, and a 323 when lift and production justify the extra weight. As a current-model reference, CAT lists the 320 GC near 22.0 tonnes, the standard 320 near 22.6 tonnes and the 323 near 25.0 tonnes, although older D-series configurations vary by boom, bucket, shoes and counterweight. The 320D usually has broader used parts familiarity; GC models favor lower-intensity work; the 323 gives more stability and payload. Recommendation: select the 320D for general resale value, 320 GC for steady lighter duty, and 323 for higher-production truck loading.
4. How do CAT 325, 330 and 336 excavators differ by job?
Use a 325 class for mobility and medium production, a 330 class for general mass excavation, and a 336 class for heavier rock, lifting and truck loading. Screening weights are roughly 25-28, 29-32 and 35-38 tonnes, but actual configuration must be checked. The 325 reduces transport and fuel burden; the 330 is a common balance for road, foundation and bulk earthwork; the 336 carries a larger bucket and maintains production in harder material. Recommendation: choose the 325 when moves are frequent, the 330 for mixed production, and the 336 only when material density and daily output use its added capacity.
5. When should I move from a CAT 340 to a 349 or 352?
Move above the 40-tonne CAT 340 class only when production, bucket payload or lifting demand pays for the added operating cost. A 340 class is suited to heavy civil work, large foundations and quarry support; 349 and 352 machines enter roughly the 49-52 tonne production range with more bucket capacity, stability and breakout force. They also require wider transport planning, more fuel and higher undercarriage and attachment budgets. A 50-tonner working below capacity is usually less economical than a correctly matched 40-tonner. Recommendation: buy the 340 for mixed heavy construction and choose 349/352 only for sustained rock, bulk excavation or large-truck loading.
6. Is a CAT 374 or 390/395 appropriate for my project?
Choose a CAT 374 or 390/395 only for continuous quarry, mine, major cut or large-scale production work. A representative 374 configuration is about 74 tonnes, while 390/395-class machines approach roughly 86-95 tonnes depending on front, counterweight, bucket and undercarriage. They can load large haul trucks quickly, but mobilization may require component removal, permits, cranes and breakbulk or heavy-lift shipping. Idle time makes their ownership cost difficult to recover. Recommendation: select a 374 for high-volume quarry production and move to 390/395 only when truck size, material and shift output clearly require the 90-tonne class.
7. Which CAT generation is better: D/D2, E/F, GC or newer series?
Choose the generation your local technicians can diagnose and support, not automatically the newest one. D and D2 machines often have lower purchase prices and familiar mechanical systems; E and F generations may improve controls and fuel management but add electronics and emissions hardware; GC versions target lower owning and operating cost in moderate duty; standard newer models prioritize production and technology. Compare local diagnostic access, emissions rules, sensor availability and rebuild support before fuel claims. Recommendation: buy D/D2 for simple support markets, GC for predictable lighter duty, and newer standard models only where electronics and after-treatment service are available.
8. How many hours are too many for a used CAT excavator?
Hours are a risk indicator, not a rejection rule. Under about 5,000 hours is a lower-hour screening range, 5,000-10,000 hours is common used territory, and above 10,000 hours needs service records, component history and a larger repair reserve. Compare meter and ECM hours with pedal, seat, joystick, pin, pump and undercarriage wear; a maintained 12,000-hour machine can be safer than a neglected 4,000-hour quarry unit. Idle-heavy utility work and breaker-heavy rock work also age components differently. Recommendation: accept higher hours only when duty history, measured wear and price all support the remaining life.
9. How do I verify CAT serial number, hours and service history?
Match the serial plate, frame identity, meter and ECM record before discussing price. Request clear photos of the product identification number, engine plate, dashboard hours and frame area, then compare them with the invoice and export documents. Product Link, dealer service history or a Product Status Report may add evidence when available, but not every older machine has complete digital records. Fresh plates, inconsistent fonts or ECM hours that differ sharply from the display require investigation. Recommendation: proceed only when machine identity and hour evidence are consistent enough to appear on the sales contract.
10. What engine tests should a used CAT excavator pass?
Require a true cold start, a hot-load test and fluid checks before accepting the engine. Compare start time, idle stability, blow-by, smoke color, oil pressure, coolant condition, leaks and abnormal noise before and after at least 30 minutes of work. Continuous blue smoke, heavy crankcase pressure, coolant in oil or an engine already warm before inspection is more serious than a brief acceleration puff. Oil analysis provides stronger evidence than fresh paint or a washed engine bay. Recommendation: reject or price a rebuild into any machine with persistent smoke, contamination, low pressure or unexplained warning codes.
11. How should I test the hydraulic pump and cylinders?
Test hydraulics hot, under load and with combined functions; a cold no-load demonstration is insufficient. Measure boom-up, arm-in, bucket-curl and swing cycle times against the correct model specification, then repeat after the oil reaches working temperature. Watch for slow combined movement, pump whine, cylinder drift, rod scoring, hose leakage and weak digging force. Pressure and case-drain tests are stronger evidence than video speed alone. Recommendation: require a continuous 20-30 minute working test and choose only a machine that maintains speed, force and stable temperature when hot.
12. How much undercarriage life should remain?
Target at least 50% measured undercarriage life or deduct a complete wear-part budget from the price. CAT Certified Used criteria use 50% remaining life as a quality reference, but ordinary used machines must be measured component by component: links, bushings, rollers, idlers, sprockets, shoes and track tension. One new component beside heavily worn mating parts does not make a healthy system. Wide shoes help soft ground but can accelerate stress on hard rock. Recommendation: buy with a written undercarriage measurement report; treat below roughly 30% remaining life as near-term replacement cost.
13. How do I check the swing bearing, final drives and travel motors?
Test swing and travel after the machine is hot, on level ground and under controlled load. Compare upper-structure play, start-stop shock, swing brake holding, final-drive noise, travel speed and straight tracking. One track lagging, metal in final-drive oil, excessive swing movement or uneven motor temperature can signal expensive repairs. There is no universal acceptable swing-play number across CAT models, so measured movement must be compared with the service limit. Recommendation: choose the machine that tracks straight, swings smoothly and has clean oils, or deduct full component repair cost before buying.
14. Which boom, stick or frame repairs are acceptable?
Accept replaceable pin and bucket wear at a discount, but treat boom, stick, carbody or counterweight repairs as high risk. Inspect both sides of the boom foot, stick-to-bucket area, cylinder mounts, swing frame and track frames for cracks, distortion, unequal gaps and welds hidden by paint. Breaker work can produce different stress from normal digging, while long-reach fronts add leverage. A sound-looking weld does not prove correct alignment or metallurgy. Recommendation: avoid structural repairs unless an independent inspector verifies alignment, weld quality and the exact repair history in writing.
15. Which bucket and attachment configuration should I choose?
Match the front equipment to material and duty before comparing excavator prices. Narrow trench buckets reduce moved material for utility work; general-purpose buckets balance loading and digging; reinforced rock buckets and hydraulic breakers need stronger pins, guards and cooling; grapples require suitable auxiliary lines; long-reach fronts trade digging force and lifting capacity for reach. A large bucket can overload a smaller machine when material density or reach increases. Recommendation: specify material, bucket volume, digging depth, attachment weight and required hydraulic flow, then verify the model load chart and auxiliary circuit.
16. How should I compare productivity and fuel use?
Compare tonnes moved per litre and cost per productive hour, not fuel litres per hour alone. Run both machines with the same material, bucket fill, swing angle, truck position and operator, then record cycle time, bucket payload, idle time and fuel consumed. A 36-tonne excavator burning more per hour can be cheaper per tonne than a 30-tonner if it fills trucks in fewer cycles; the reverse is true when the larger machine waits. Recommendation: choose the excavator with the lowest cost per required tonne at your real duty cycle, not the lowest hourly fuel number.
17. How does operating weight change shipping and transport cost?
Transport planning becomes a buying decision above each width, height and axle-load limit, not only at a model number. Compact 6-15 tonne excavators may fit container or flat-rack plans after measuring and partial dismantling; 20-40 tonne machines commonly need flat rack, RoRo or breakbulk; 50-90 tonne machines may require boom, stick, bucket, counterweight or track-frame removal plus cranes and permits. Two machines with the same model can ship differently because of shoes and front equipment. Recommendation: obtain measured transport dimensions, component weights and two freight methods before paying a deposit.
18. What evidence should I request when buying a CAT excavator remotely?
Do not pay from edited clips or a small exterior photo set. Request at least 40 clear photos and a continuous 15-20 minute video showing the serial plate, meter, true cold start, engine bay, hydraulic pump, boom and stick, swing bearing, track system, final drives, bucket pins, full travel and digging under load. Compare image timestamps, yard background and machine details, then add a live video call or independent inspection for higher-value units. Recommendation: proceed only when identity, current location, hot operation and major-component condition are supported by one consistent evidence package.
19. How do I calculate the real landed cost?
Calculate landed cost before ranking machines by advertised price. Add machine price, China inland transport, inspection, cleaning, dismantling, crane and loading, ocean freight, insurance, destination handling, duty or tax, local permits, reassembly and inland delivery. Then add an initial repair reserve of roughly 8-15% depending on machine size, evidence and component condition. A low-priced 349 with weak undercarriage and expensive breakbulk shipping can cost more than a cleaner 340. Recommendation: compare itemized FOB and CIF options to the same port and approve only the lowest risk-adjusted landed cost.
20. What is the final decision rule before buying?
Buy the CAT excavator with the highest verified value score, not the lowest price. Score mechanical and structural condition 35 points, application and operating-weight fit 25, local parts and diagnostic support 15, landed cost 15, and identity or seller evidence 10. Require at least 75/100, then apply a zero-tolerance rule to unresolved serial identity, engine contamination, hydraulic failure, major structural cracks or unsafe repairs. A cheaper machine loses when one pump, undercarriage or transport problem removes the saving. Recommendation: approve the purchase only after the score, inspection exceptions and repair reserve are written into the decision file.
Used CAT excavators from 6 to 90 tonnes
These current listings cover the main operating-weight decisions. Confirm serial-specific operating weight, year, hours, front equipment, undercarriage, working condition and shipping cost before selecting a machine.
FAQ: final checks before purchase
Are CAT and Caterpillar excavators the same brand?
Yes. CAT is Caterpillar's product brand. Model identity still needs to be verified from the product identification number because decals and paint alone do not prove the exact model or configuration.
Can a CAT excavator hour meter be trusted?
Treat the display as one data point. Compare it with ECM hours, service records, pedal and joystick wear, hydraulic condition and undercarriage measurements before using hours to value the machine.
Is a CAT GC excavator always cheaper to operate?
Not always. GC models target lower owning and operating cost in suitable duty, but a standard model may cost less per tonne when higher hydraulic power, lifting or production prevents truck waiting and extra cycles.
Can a used CAT excavator ship in a container?
Some compact machines can ship in a container after exact measurement and preparation. Medium and large excavators commonly require flat rack, RoRo or breakbulk, often with the front equipment or counterweight removed.
Which spare parts should ship with a used CAT excavator?
Prioritize model-specific filters, belts, hose seals, bucket teeth, cutting edges, common sensors and any items difficult to source locally. Match every part to the serial number before shipment.
When is an independent CAT excavator inspection worth the cost?
Use one for high-value machines, incomplete service evidence, breaker or quarry history, structural repairs, or when the buyer cannot absorb a pump, engine, final-drive or undercarriage failure.
Sizing rule: operating weight is only the first filter. Use the serial-specific specification and operation manual for lifting, bucket, hydraulic and transport limits, then confirm the actual machine with photos, continuous hot working video and inspection measurements.
Send the job, required operating weight, budget and destination port.
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