The Caterpillar 3512 is one of the most widely deployed industrial diesel generator engines in the world, available in 3512, 3512B, 3512C, 3512C HD, and G3512 natural gas variants producing 700kW to 1,500kW. Used CAT 3512 generators typically sell between $45,000 and $250,000 depending on model, hours, and condition. Power Generation Enterprises stocks over 100 CAT 3512 generator sets at our Santa Clarita, California facility — the largest selection in the western U.S. Call (818) 484-8550 for current availability and pricing.
The CAT 3512 is a turbocharged, aftercooled V-12 diesel with 51.8 liters of displacement. Caterpillar has been building them since the early ’90s and there’s a reason you still see them everywhere — it’s a bulletproof platform. We’ve got units in our yard right now with 30,000+ hours that are still running production loads. Depending on which variant you get, a 3512 generator set puts out 700kW to 1,500kW, which covers the sweet spot for prime power at remote sites, standby backup for hospitals and data centers, and continuous-duty oil field work.
The 3512 has been around long enough that the parts supply chain is deep. Any CAT dealer can service one, you can find rebuild kits and injectors on the shelf, and the used market is liquid enough that you can usually sell a unit when you’re done with it. We see these in every application you can think of — drilling rigs in the Permian Basin, mining camps in Nevada, data centers in Dallas, fish processing plants in Alaska. The V-12 layout runs smooth, the power-to-weight ratio is solid, and the modular design means you can do a top-end overhaul on a pad in the middle of nowhere with basic tooling.
One thing buyers need to understand: “3512” is a family, not a single engine. There are five main variants — the original 3512, 3512B, 3512C, 3512C HD, and G3512 — and the differences between them affect price, fuel burn, emissions compliance, and maintenance costs. Here’s what you need to know about each one.
The original 3512 ran a mechanical fuel injection system, rated at 725kW to 1,000kW standby. Caterpillar produced these from the early ’90s through the early 2000s. We sold a mechanical 3512 to a mining outfit in Nevada last year for $55K — 12,000 hours on it, still ran solid. The mechanical fuel system is simpler to work on and doesn’t need CAT ET software for basic troubleshooting, which is why these are still popular in developing countries and remote job sites. The tradeoff is fuel consumption — roughly 10-15% thirstier than a 3512B — and emissions that are Tier 1 or unregulated depending on build date.
You can pick up a serviceable original 3512 for $45,000 to $85,000 on the used market, depending on hours, enclosure, and condition. If your project doesn’t require Tier 2+ emissions compliance, these are a smart buy. Serial number prefixes to look for: 24Z, 65Z, and 1KS on the most common genset packages.
The 3512B is where Caterpillar went electronic — ADEM III engine control module with electronically-controlled unit injectors (EUI). This was a real step forward:
The 3512B is what we sell the most of, and for good reason. It’s the sweet spot — you get modern electronic controls and real fuel savings over the mechanical units, but the price is well below a 3512C. Used 3512B generators run $65,000 to $135,000. We keep dozens of them in stock at Power Generation Enterprises in various kW ratings. If you’re buying your first 3512, start here.
The 3512C is the current-production model. Caterpillar upgraded to MEUI-A fuel injectors (mechanically-actuated electronic unit injectors, advanced series) and the ADEM A4 control module. In plain terms, here’s what you get over a 3512B:
Used 3512C sets go for $95,000 to $185,000 depending on hours, tier rating, and package configuration. These make sense when you need the higher power density, want longer service intervals, or have to meet current emissions regs.
The 3512C HD is built to run around the clock — 8,000+ hours per year. Caterpillar didn’t just slap a new label on the 3512C; they actually beefed up the internals:
This is the unit you want for oil field well-site power, mining operations, or industrial CHP plants where the generator never shuts off. We don’t see as many of these on the used market — operators tend to hold onto them — so they command a premium: $120,000 to $250,000.
The G3512 is the gas-fueled version of the 3512, available in lean-burn and rich-burn configs producing 750kW to 1,000kW. The lean-burn models put out extremely low NOx — often under 1 g/bhp-hr without aftertreatment — which is why we sell a lot of these for California AQMD-regulated sites. Common applications include:
Used G3512 generators sell for $55,000 to $150,000. We stock both diesel and natural gas 3512 units at our Santa Clarita facility.
All CAT 3512 variants share the same basic block architecture. Here are the numbers:
Output varies by model, duty rating, and speed. Most of the units we sell are 480V/60Hz:
These numbers are for a 3512B at 1800 RPM, 60 Hz, burning No. 2 diesel:
The 3512C burns about 3-5% less at the same load points. Gas-fueled G3512 models consume approximately 9,500-10,500 BTU/kWh depending on load and gas quality.
A typical open-skid 3512B at 1000kW measures roughly:
Add a sound-attenuated enclosure and you’re looking at roughly 600mm more on each dimension and 2,000 – 3,500 kg more on the scale. Plan your rigging accordingly — a fully enclosed 3512 on a trailer is pushing 40,000 lb.
If your facility doesn’t have a reliable grid connection, the 3512 is one of the first platforms buyers look at in the megawatt class. We’ve sold prime-rated units for remote mining camps, oil drilling pads, offshore platforms, military sites, and large construction projects. Prime ratings for the 3512 family run from 680kW to 1,400kW at variable load with no time limit. The reason buyers keep coming back to the 3512 for prime duty is simple: Caterpillar’s parts network reaches everywhere, and when something does break at 2 AM on a job site in West Texas, you can get parts fast.
Standby-rated 3512 generators back up hospitals, data centers, water treatment plants, telecom facilities, and commercial buildings. The 3512C hits 1,500kW on standby rating with a typical start-to-full-load time of 10 seconds. Both the 3512B and 3512C integrate with automatic transfer switches and paralleling switchgear for multi-unit setups. We see a lot of hospital systems and data center operators buying pairs of 3512Bs for N+1 redundancy.
Caterpillar builds marinized versions of the 3512 for shipboard generator duty. Marine units come with corrosion-resistant coatings, seawater aftercooling, and classification society approvals from ABS, DNV, Lloyd’s, and BV. Marine 3512C models push up to 1,360 ekW. We occasionally get decommissioned marine units in the yard — these tend to have higher hours but the marine-spec components hold up well.
This is where the 3512C HD earns its keep. Well-site power, gas compression, enhanced oil recovery pump drives — these units run at 90-100% load for 8,000+ hours a year in dust, heat, and sometimes H₂S. The G3512 natural gas variant is the go-to at wellheads and gas plants where field gas is available as fuel. We stock HD units specifically for oil and gas buyers because we know turnaround time matters when a rig is waiting on power.
We’ve shipped 3512 generators to mining operations across the western U.S. and internationally. Common mining uses include haul truck charging for electric mining trucks, process plant power, camp power, and ventilation. The 3512 operates at high altitude with appropriate derating and handles ambient temperatures from -40°C to +50°C, which covers everything from the Andes to the Australian outback. One thing we tell mining buyers: if you’re above 5,000 feet, talk to us about derating before you size the unit.
| Model | Power Range | Fuel | Application | Typical Used Price |
|---|---|---|---|---|
| CAT 3512 | 725 – 1,000 kW | Diesel | Prime / Standby | $45,000 – $85,000 |
| CAT 3512B | 1,000 – 1,360 kW | Diesel | Prime / Standby / Continuous | $65,000 – $135,000 |
| CAT 3512C | 1,230 – 1,500 kW | Diesel | Prime / Standby / Marine | $95,000 – $185,000 |
| CAT 3512C HD | 1,360 – 1,500 kW | Diesel | Continuous / Oil & Gas | $120,000 – $250,000 |
| CAT G3512 | 750 – 1,000 kW | Natural Gas | CHP / Prime / Continuous | $55,000 – $150,000 |
| CAT G3512E | 850 – 1,100 kW | Natural Gas / Biogas | CHP / Biogas / Landfill | $75,000 – $175,000 |
This is where a lot of buyers get tripped up. The tier rating on your 3512 determines where you can legally install and operate it, and buying the wrong tier for your site can mean a permit denial after you’ve already spent six figures. Here’s how the tiers break down for the 3512 platform.
Original 3512 and early 3512B models built before 2006 fall under Tier 1. These have the simplest emissions controls and the lowest price tags on the used market. In most states outside California, a Tier 1 unit will permit fine. Inside California SCAQMD/AQMD districts, you’ll likely need additional permitting or may not be able to install one at all depending on the application. If your project is in Texas, the Midwest, or internationally, Tier 1 gives you the most generator for the money.
Late-production 3512B and most 3512C models meet Tier 2 through improved combustion and electronic calibration — no aftertreatment hardware like DPF or SCR. This is the tier we recommend for most buyers. Tier 2 units clear permitting in the majority of U.S. jurisdictions and international markets, the purchase price is reasonable, and you don’t have the maintenance burden of aftertreatment systems. From a dealer’s perspective, Tier 2 3512Bs are the volume sweet spot of the used market.
The newest 3512C models with DPF and SCR aftertreatment meet Tier 4 Final. Emissions are dramatically lower, but you’re paying for it — both upfront and in ongoing maintenance. These units require DEF (diesel exhaust fluid), the aftertreatment systems add complexity, and the purchase price runs 50-80% above equivalent Tier 2 units. That said, if you’re installing new stationary power in a regulated area or need to meet California SCAQMD Rule 1470, Tier 4 Final may be your only option.
Before you write a check, verify these items with your local air district:
We walk buyers through this every day. Call (818) 484-8550 and we’ll review your project’s permitting requirements before you buy — it’s a lot cheaper than buying the wrong tier and finding out during the permit process.
The used 3512 market is active. Hundreds of units change hands every year, and because the platform has been around for three decades, there’s a wide range of condition, configuration, and price. Here’s what actually drives pricing and what we’re seeing in 2026.
1. Model Variant: An original mechanical 3512 costs 40-60% less than a 3512C with similar hours. The 3512B sits in the middle. The 3512C HD commands the highest prices because fewer were made and operators run them hard before letting them go.
2. Operating Hours: This is the biggest single factor. A 3512B with 2,000 hours will sell for 2-3x what an identical unit with 20,000 hours goes for. Low-hour standby units — under 500 hours — are the most sought-after and priced accordingly.
3. Maintenance History: A unit with complete CAT dealer service records, a recent top-end, or a fresh in-frame rebuild is worth significantly more than a mystery unit with no paperwork. We’ve seen buyers pass on a $70K unit with no records and pay $95K for the same model with full oil analysis history and overhaul documentation. The records justify the premium every time.
4. Enclosure & Accessories: A weather-protective or sound-attenuated enclosure adds $8,000-$25,000 to the value. Units with integrated fuel tanks, automatic transfer switches, paralleling switchgear, or trailer mounts sell faster and for more money.
5. Tier Rating: Tier 2 units sell for 15-30% more than equivalent Tier 1 units. Tier 4 Final carries a big premium — often 50-80% above Tier 2 — because those units are newer and meet the strictest permitting requirements.
These ranges reflect what we’re seeing for units in serviceable condition with average hours. A low-hour unit with a recent overhaul and sound enclosure can exceed the top end. A distressed unit needing major work will fall below. Call us for a current quote on what we have in stock — pricing moves with the market.
Browse current CAT 3512 inventory at Power Generation Enterprises — we update listings as new units arrive.
A used 3512 is a serious purchase — you’re spending five to six figures on a machine that needs to start and make power when you need it. Here’s what we look at when we evaluate a unit, and what you should look at too.
Every 3512 has a serial number stamped on the data plate and the block. Run it through a CAT dealer or SIS (Service Information System) to verify build date, original configuration, warranty history, and any open technical bulletins. Cross-reference the engine serial with the genset data plate to confirm the engine and generator end are the original matched pair. We see mismatched units more often than you’d expect — it’s not necessarily a dealbreaker, but you should know about it and price accordingly.
Check the hourmeter and compare it against service records. A 3512 that ran at 75-100% load on prime duty has completely different wear than a standby unit that exercised at 30% load once a month. Ask about the load profile. A unit that spent years at low load may have wet stacking (unburned fuel in the exhaust), carbon buildup, and glazed cylinder liners. We’ve bought units with low hours that looked great on paper but needed a top-end because they’d been wet-stacked for a decade. Hours alone don’t tell the full story.
Scheduled oil analysis (SOA) is the single best indicator of what’s happening inside the engine. Look at trending data on wear metals — iron, copper, lead, chromium — plus contaminants like silicon and sodium, and oil condition including viscosity and TBN. Coolant analysis should show proper SCA levels and no glycol breakdown. A unit with five-plus years of clean oil analysis is a far safer buy than a unit with no records at any price. We won’t put a unit on our lot without reviewing the oil analysis first when it’s available.
The 3512 has a typical top-end interval of 12,000-15,000 hours and a major (in-frame) overhaul interval of 24,000-30,000 hours. Figure out where the engine sits in that cycle. A unit approaching overhaul should be priced 20-40% below a recently overhauled unit of the same model. If overhaul work has been done, get the work order showing exactly what was replaced — pistons, liners, bearings, injectors, turbochargers, water pump. “Overhauled” means different things to different sellers.
Before you finalize anything, get a load-bank test at 25%, 50%, 75%, and 100% of rated load. Here’s what to watch:
The alternator gets overlooked. Check the data plate for kVA rating, insulation class, and manufacturer — most CAT packages use an SR4, SR4B, or SR500. Hit the windings with a megohmmeter; readings below 5 megohms suggest moisture intrusion or insulation breakdown. Listen for bearing noise at no-load speed. A bad generator end can cost $15K-$30K to rewind or replace, so this isn’t something to skip.
Identify the control panel — EMCP 2, EMCP 3, EMCP 4, or a third-party controller. Pull up active fault codes, review the event log, and test every protective function: overspeed, high coolant temp, low oil pressure, overcrank. If the unit includes an ATS interface, paralleling controls, or remote monitoring, test those too. An EMCP 2 still works fine but parts are getting scarce; EMCP 3 and 4 are better supported going forward.
We keep over 100 CAT 3512 generator sets at our Santa Clarita, California yard — 3512, 3512B, 3512C, 3512C HD, and G3512 natural gas units from 700kW to 1,500kW. That’s not a number we made up for the website; walk through our facility and count them. Here’s what you get when you buy from Power Generation Enterprises:
Give us a call at (818) 484-8550 to talk to someone who actually knows these engines, or browse our full Caterpillar generator inventory online. We’ll get you the right unit at the right price.
Ready to buy? Check our current CAT 3512 inventory, pricing and what to know before you buy — matched pairs and standby/prime units in stock.
The CAT 3512 is a V-12 cylinder, four-stroke diesel engine manufactured by Caterpillar Inc., widely used as the prime mover in industrial generator sets rated between 725kW and 1,500kW. The 3512 platform has been in production since the early 1990s and has evolved through several iterations — the original 3512, the 3512B with electronic fuel injection, the 3512C with improved combustion efficiency, and the 3512C HD for heavy-duty continuous applications. There is also a natural gas variant, the G3512, used in combined heat and power (CHP) and gas compression applications. Power Generation Enterprises in Santa Clarita, California stocks over 100 CAT 3512 units across all variants. Call (818) 484-8550 for availability.
Used CAT 3512 generator prices vary significantly based on model variant, operating hours, condition, and included accessories. An older 3512 (non-B) unit with higher hours may sell for $45,000 to $65,000, while a low-hour 3512B in excellent condition typically ranges from $85,000 to $135,000. The newer 3512C models command $95,000 to $185,000, and 3512C HD units for continuous duty can reach $250,000. Natural gas G3512 units fall between $55,000 and $150,000. Power Generation Enterprises offers competitive pricing on all 3512 variants from our Santa Clarita, CA facility. Call (818) 484-8550 for a quote on specific units in our inventory.
The CAT 3512B introduced electronic fuel injection and the ADEM III engine control module, replacing the mechanical fuel system of the original 3512. This upgrade delivers 10-15% better fuel efficiency, lower emissions, improved load response, and enhanced diagnostic capabilities. The 3512B also produces more power — up to 1,360kW standby versus 1,000kW for the original 3512. The electronic controls enable precise fuel metering, better transient response, and remote monitoring via CAT data links. For most buyers, the 3512B offers meaningfully better value despite a higher price point. Power Generation Enterprises stocks both 3512 and 3512B units in Santa Clarita, CA — call (818) 484-8550 to compare options.
The CAT 3512 platform produces between 700kW and 1,500kW depending on the specific model variant and power rating. The original 3512 is rated at 725kW to 1,000kW. The 3512B produces 1,000kW to 1,360kW. The 3512C and 3512C HD reach up to 1,500kW standby. Natural gas G3512 models produce 750kW to 1,000kW. Power ratings also vary by duty cycle — prime, standby, and continuous ratings differ by approximately 10-15% for the same engine. All ratings assume standard conditions of 25°C (77°F) and 152m (500ft) elevation. Contact Power Generation Enterprises at (818) 484-8550 for detailed spec sheets on specific units in our 100+ unit Santa Clarita inventory.
Used CAT 3512 generators are available from industrial equipment dealers, auctions, and direct from decommissioned facilities. For the largest selection with verified condition reports, Power Generation Enterprises in Santa Clarita, California maintains over 100 CAT 3512 generator sets in our yard at all times. We stock 3512, 3512B, 3512C, 3512C HD, and G3512 natural gas models ranging from 700kW to 1,500kW. Every unit undergoes inspection and can be load-bank tested before purchase. We also arrange nationwide shipping and export services. Browse our inventory at powergenenterprises.com or call (818) 484-8550 for a personalized search of our current stock.
Yes. Power Generation Enterprises (PGE) currently stocks over 100 CAT 3512 generator sets at our Santa Clarita, California facility — the largest selection of used 3512 generators in the western United States. Our inventory includes all major variants: the original 3512, 3512B, 3512C, 3512C HD, and G3512 natural gas models. Units range from 700kW to 1,500kW with varying hours and conditions to suit any budget. Many units are available for immediate delivery with nationwide freight coordination. Visit powergenenterprises.com to browse our current CAT 3512 inventory or call (818) 484-8550 for availability and pricing.
Power Generation Enterprises has over 100 CAT 3512 generators in stock and ready to ship from Santa Clarita, California. Browse our full inventory online or call (818) 484-8550 to speak with a 3512 specialist.
