DIESEL ENGINE
REPAIR & OVERHAUL
SERVICES

OEM-Trained Engineers

30% Faster
Turnaround Time
vs. OEM
Benchmark

30% Cost Reduction
with technology,
maintaining
reliability until the
next overhaul

Timely
Deployment
(Access to
Multiple
PRs & CDC)

Comprehensive
Support On-site,
Off-site, Remote,
including
Riding Squad

12-Month
Workmanship
Warranty

Access to Specialized
Tools such as Chris
Marine Cylinder Liner
Honing, Valve Seat
Machining Tool

Detailed
Work Completion
Report

Home » ARM » Repair Overhaul » Marine Diesel Engine Repair Services

Diesel engine repair services help restore engine performance, improve reliability, and reduce the risk of unexpected breakdowns in marine, oil & gas, and industrial applications. At Neptunus, we specialise in the repair, maintenance, and overhaul of 4-stroke high- and medium-speed diesel engines, delivering expert technical support to keep critical equipment operating efficiently. With over three decades of industry experience, we provide reliable diesel engine solutions that minimise downtime, extend engine life, and support uninterrupted operations.

Our team of skilled engineers and technicians brings extensive expertise in working with all major engine brands, including Niigata (OEM Authorized), CAT (Independent Service Provider), EMD (OEM Authorized), Wartsila (Independent Service Provider), Yanmar(Independent Service Provider), MAN(Independent Service Provider), MTU(Independent Service Provider), and Detroit(Independent Service Provider). Whether it’s an emergency repair or a scheduled overhaul, Neptunus offers flexible diesel engine repair services tailored to the specific needs of vessel and rig owners. From in-situ diesel engine repairs performed directly on-site to comprehensive workshop overhauls, we ensure efficient, high-quality service that enhances engine performance and longevity. As part of our diesel engine service offering, we undertake:

Cylinder head repair
Crankshaft inspection and alignment
Fuel injection system calibration
Turbocharger overhauls
Engine performance diagnostics
Spare parts support

We tailor every repair strategy to engine condition, application, and customer goals—ensuring reliable performance and extended engine life. Through our dependable diesel engine repair services, customers benefit from reduced fuel consumption, extended overhaul intervals, and fewer unplanned outages.

Neptunus has extensive experience delivering services both domestically and internationally. We perform diesel engine repairs either at our advanced workshop or in-situ at major Indian ports including Mumbai, Cochin, Goa, Kolkata, Chennai, Visakhapatnam, and Haldia. Internationally, we serve clients across South Asia, the Middle East, Europe, Africa, and beyond—ensuring global support with consistently high standards.

Send in your Enquiry for a Quote

Why choose Neptunus?

3 Decades of
Service Excellence

Engine & Propulsion
End-to-End Solutions

2500+ Successful Projects Delivered Worldwide

Trusted by 100+
Satisfied Customers

Dedicated Experts to
Address Emergencies

Diesel Engine Repair & Overhaul Service at Neptunus

In addition to diesel engine services, we also specialize in Propulsion Systems Repair services for various leading brands, including Kawasaki, Nakashima, and Kamome. Our expertise ensures reliable maintenance and optimal performance. We cater to a wide range of propulsion system needs, delivering high-quality repair solution.

Diesel Engine Brands For Which We Provide Repair & Overhaul Service

The team's exceptional skills and remarkable teamwork have greatly contributed to the success of completing the job on time. Thanks to their dedication, the job was completed in 9 days within timelines, despite the spare parts being delayed. We are grateful for Neptunus' unwavering support and exceptional service, and we hope to work again with you on our next project.

We are proud to be one of the largest tug boats operators from India. Most of our vessels run on Niigata engines that are being serviced very reliably and efficiently by Neptunus Power Plant Services for over two decades. One of these vessels, Ocean Spirit needed a re-configuration and programming of a critical controller circuit card and we asked Neptunus to do this during the one day scheduled downtime. However, to our delight, the Neptunus service team worked smartly to do most of the coding and programming work offline to save the on-vessel execution time. As a result, the job was done quickly during normal working hours without disturbing the operations. This allowed us to utilize our scheduled downtime for other maintenance activities. I wish to appreciate this great deal of planning and customer centricity shown by the Neptunus service team and look forward to a lasting relationship.

I am writing this mail on behalf of Rig Main Engine #4 TOH job done by Neptunus Team. I would like to take an opportunity to first of all thank Neptunus Team for doing the job on time.We appreciate the Disassembling/Assembling procedure done by Team. They worked as per the OEM procedure and the quality of their work was excellent.The work was completed safely without any incident. We wish them all the best for their future. Please improve communication from base office according upgrade spare parts and unnecessary spares order but not in using of 1 St Toh list ,please refuse extra item on next TOH.

We truly appreciate the way the entire job was carried out by the Neptunus team, from meticulous planning to seamless execution. Thanks to their dedication and expertise, the job was completed in just four days. We are grateful for Neptunus' unwavering support and exceptional service, and we look forward to collaborating with them again on future projects.