Caterpillar G3516H
1,966 ekW continuous with a published full-load heat rate down to 8,047 Btu/ekW-hr and a NOx range of 0.50 to 1.00 g/bhp-hr
Caterpillar G3516H is one of 23 gas engines tracked in the SecondWatt catalogue, each with specifications, lead times and indicative secondary-market pricing.
Caterpillar G3516H: 1,966 ekW continuous at 0.8 pf with a full-load heat rate to 8,047 Btu/ekW-hr. Specs, used pricing and inspection points.
The Cat G3516H is a continuous-duty gas generator set published at 1,966 ekW with pumps and 1,982 ekW without pumps at 0.8 power factor, inside a rating band of 1,419 to 2,027 kW. It is the 16-cylinder member of Caterpillar's long-stroke H-series, sharing the 170 mm bore and 215 mm stroke of the G3520H at 78 L rather than 97.5 L. Two builds are published: Humidity/Fuel Tolerant at 11.1 compression and High Efficiency at 12.1. Full-load fuel consumption with fan runs 8,047 to 8,642 Btu/ekW-hr on the High Efficiency build and 8,115 to 8,784 on the tolerant build. NOx is published across 0.50 to 1.00 g/bhp-hr. The package measures 7,003 by 1,955 by 2,408 mm with a dry weight of 18,315 kg, which is 6,485 kg lighter than the G3520H for roughly 78 percent of the output. The H-series block is worth understanding before purchase. It is not the 190 mm-stroke Cat 3500 block used by the G3516 FAST RESPONSE and the G3516C, so a G3516H is not a drop-in equivalent to a plain G3516 despite the shared designation. Confirm stroke on the data plate: 215 mm means H-series and 190 mm means the 3500 block.
Why it matters
It is the efficiency option in the 2 MW class with a complete public specification behind it. Caterpillar publishes full-load heat rate, NOx, geometry, dimensions and dry weight for this model, which is more than it publishes for the FAST RESPONSE package it markets hardest at data centers. That makes it the easier model to underwrite.
Who buys it
Continuous-duty buyers in the 1.4 to 2 MW block who are optimising fuel cost rather than buying standby capacity. Industrial cogeneration and municipal operators running high annual hours. Buyers who want H-series efficiency at a lighter, smaller footprint than the G3520H, where pad loading or crane access constrains the site.
Role in the data center
Continuous behind-the-meter prime power at roughly 2 MW per set, in plants sized as multiple units rather than single machines. It is the efficiency counterpart to the G3516 FAST RESPONSE, which is optimised for a cold start in under eight seconds instead. Caterpillar publishes more of this model's numbers than of the FAST RESPONSE package, so it is easier to model in a twenty-year total cost comparison even though Caterpillar markets the FAST RESPONSE harder at data centers.
Key specifications
| Continuous rating with pumps | 1,966 ekW at 0.8 pf |
|---|---|
| Continuous rating without pumps | 1,982 ekW at 0.8 pf |
| Published rating band | 1,419 to 2,027 kW |
| Heat rate at 100 percent load with fan, High Efficiency | 8,047 to 8,642 Btu/ekW-hr |
| Heat rate at 100 percent load with fan, Humidity/Fuel Tolerant | 8,115 to 8,784 Btu/ekW-hr |
| Bore | 170 mm (6.7 in) |
| Stroke | 215 mm (8.5 in) |
| Displacement | 78 L (4,765 cu in) |
| Cylinders | 16 count |
| Compression ratio | 11.1 tolerant or 12.1 High Efficiency ratio |
| NOx | 0.50 to 1.00 g/bhp-hr |
| Dimensions | 7,003 x 1,955 x 2,408 mm |
| Dry weight | 18,315 (40,384) kg (lb) |
| Subpart JJJJ NOx ceiling for this class | 1.0 g/HP-hr or 82 ppmvd at 15 percent O2 regulatory limit |
Technical summary
Continuous rating: 1,966 ekW with pumps, 1,982 ekW without pumps, at 0.8 power factor. Published rating band: 1,419 to 2,027 kW. Heat rate at 100 percent load with fan: 8,047 to 8,642 Btu/ekW-hr High Efficiency. Heat rate at 100 percent load with fan: 8,115 to 8,784 Btu/ekW-hr Humidity/Fuel Tolerant. Bore and stroke: 170 mm by 215 mm; displacement 78 L (4,765 cu in), 16 cylinders. Compression ratio: 11.1 Humidity/Fuel Tolerant or 12.1 High Efficiency. NOx: 0.50 to 1.00 g/bhp-hr. Dimensions: 7,003 by 1,955 by 2,408 mm. Dry weight: 18,315 kg (40,384 lb). Engine speed: the 60 Hz sheet lists 1,500 rpm, which does not reconcile with 60 Hz; see variations.
Major variations
Two builds are published: Humidity/Fuel Tolerant at 11.1 compression and High Efficiency at 12.1. The High Efficiency build is roughly 68 to 142 Btu/ekW-hr better at full load, trading fuel and ambient tolerance for heat rate. One Caterpillar document inconsistency is worth knowing before purchase. Caterpillar's 60 Hz H-series and K-series sheets list an engine speed of 1,500 rpm, and the CG170 brochure lists 1,500 rpm alongside both 50 and 60 Hz outputs. A 1,500 rpm machine on a synchronous alternator produces 50 Hz on four poles, not 60 Hz. The pattern appears on at least three separate Caterpillar documents, so it is not a single typo. A resale listing describes a 60 Hz G3520H at 1,800 rpm, but a reseller listing is not a substitute for the OEM specification; confirm engine speed on the nameplate.
Configurations and options
Ratings are published with and without engine-driven pumps, 1,966 against 1,982 ekW. State which you mean, because resale listings use the two figures interchangeably. The H suffix marks the long-stroke 170 by 215 mm block. Caterpillar's wider G3516 designation also covers plain, B, C, K and LE generations built on the 190 mm-stroke 3500 block, and those are different engines sharing a model number.
Compatibility and dependencies
The G3516 and the 3516B diesel share the Cat 3500 block. Caterpillar publishes 170 mm bore, 190 mm stroke, 69 L and a V16 layout on both. They are not the same engine: the diesel is a 14.0:1 compression-ignition unit with electronic unit injection, while the gas set is spark-ignited with a gas fuel train and a different emissions package. What carries across is parts overlap, shared service tooling and a Cat technician base already fluent in the 3500 platform. What does not carry across is ratings, duty, overhaul intervals or the emissions rule. Diesel sets fall under 40 CFR 60 Subpart IIII for compression ignition; this one falls under Subpart JJJJ for spark ignition.
Pricing and availability
Comparable secondary-market band: 273.31–505.55 $ per kW. Trend: rising Condition in this category is dominated by hours to overhaul, not by model year or cosmetic state. A 40,000-hour engine three years from a major is worth materially less than an older unit fresh out of one, and the resale boards rarely publish hours at all. That is why the used spread is so wide. Ask for hours since major and hours since top-end before any other question, and treat a listing without an hour meter reading as unpriceable. Lead time, new: The only dated model-specific schedule on the public record is the Monarch alliance: announced 28 January 2026 with G3516 deliveries running September 2026 through August 2027, which puts first units at roughly eight months from announcement at 2 GW scale. Global Power Supply publishes 26 to 39 weeks for natural gas gensets of 70 to 500 kW in 2026 and no band at all above 500 kW, which is the range the G3516H occupies. Do not extrapolate it upward. Caterpillar publishes no lead time for any gas genset and Cat dealer pages do not quote one.. Lead time, used or refurbished: No published lead time for used G3516H units. The one listing on record was a batch of eight new 2022 units offered together and subsequently sold, which suggests availability moves in blocks rather than as a steady supply.. Warranty, new: The one new G3516H offering on record was advertised as carrying Caterpillar factory warranty, which is a reseller claim rather than a Caterpillar-published term..
Lifecycle and maintenance
Caterpillar publishes no MTBF and no overhaul interval in hours for the G3516H. The only Cat-published maintenance interval anywhere in the gas line is up to 4,000 operating hours on the CG170 series. MWM publishes 48,000 to 80,000 hours to major overhaul on the CG-series engines Caterpillar also owns, which are different engines, so those are MWM figures rather than Caterpillar figures for this model. The transactional evidence in this category is more useful: Caterpillar gas sets change hands at 37,000 to 62,000 hours and still carry value, so hours to overhaul rather than model year is the number that sets price.
Thermal and emissions profile
Caterpillar publishes the G3516H across a NOx range of 0.50 to 1.00 g/bhp-hr. The upper figure is exactly the 40 CFR 60 Subpart JJJJ ceiling for lean-burn natural gas non-emergency spark-ignition engines at or above 500 HP, which the rule sets at 1.0 g/HP-hr or 82 ppmvd at 15 percent O2. A set ordered at 1.00 g/bhp-hr meets the federal rule natively but with zero margin, so an annual stack test has nowhere to drift. The 0.50 g/bhp-hr setting is an engine-out tune rather than aftertreatment. Selective catalytic reduction is a capital line item that appears when a local permit rather than the federal rule governs, which is the usual case in a non-attainment area. No carbon monoxide or formaldehyde figure is published; formaldehyde falls under NESHAP RICE.
Common failure points
- Detonation from low methane number gas — Knock under load, rising exhaust temperature, controller retarding timing
- Spark plugs and ignition coils — Misfire, rough running, rising carbon monoxide, output derate
- Charge-air and aftercooler fouling — Charge air temperature rising and heat rate drifting above the 8,047 Btu/ekW-hr baseline
- Exhaust valve and seat recession — Compression falling on one cylinder, exhaust spread widening, hard starting
- Emissions drift past Subpart JJJJ — Annual stack test returns NOx above 1.0 g/HP-hr or 82 ppmvd at 15 percent O2
- Turbocharger bearing failure — Oil in the charge air, surge, sudden loss of boost and output
- Wrong-block substitution at purchase — A unit sold as a G3516 that is actually the 190 mm-stroke 3500 block, or the reverse
Inspection checklist
Hours since major overhaul: the dominant price driver in this category, ahead of model year. Hours since top-end: the sibling CG-series calls cylinder head work at 16,000 to 40,000 hours. Stroke on the data plate: 215 mm confirms H-series; 190 mm means it is a 3500-block G3516. Nameplate duty: rated continuous, which is not interchangeable with the 1,500 ekW standby G3516. Power factor: the 1,966 ekW rating is quoted at 0.8 pf, not 1.0 pf. With-pumps or without-pumps rating: the difference is 16 ekW, 1,966 against 1,982. Build variant: Humidity/Fuel Tolerant at 11.1 compression or High Efficiency at 12.1. Heat rate verified under load: expect 8,047 to 8,642 Btu/ekW-hr on a High Efficiency build. NOx tune: published from 0.50 to 1.00 g/bhp-hr; the upper end sits on the federal ceiling. Engine manufacture date: the Subpart JJJJ ceiling binds engines built on or after 1 July 2010.
Procurement channels
New units go through Cat dealers and Cat dealer pages price as Request a Quote. Named dealers holding gas stock include Quinn, Hawthorne, Empire, Western States, Cleveland Brothers, Carter, Stowers, Foley, Holt, Milton, Mustang, Ring Power, Toromont, Wheeler and Boyd CAT. The used channel is quote-driven and deep in Texas and western Canada. DEPCO Power Systems publishes more numbers than anyone else; Industrial Motor Power, Power Generation Enterprises, McKain, Powersafe, Collicutt, Lenmark, NineX, Aaron Equipment and Worldwide Power Products carry inventory but mostly withhold price. Price opacity is the defining feature here.
Regional notes
Confirm frequency and voltage on the nameplate before assuming a listing is North American spec. Caterpillar's own claim for the Cat dealer network is 24/7 service, 99 percent parts availability and a 24-hour response guarantee. That is a Caterpillar claim rather than a measured figure. It is still the commercial argument that matters most in this category, because every large competitor is European or thinner on the ground in North America.