Caterpillar marine engines we service
Our diesel technicians work across the Caterpillar marine range — propulsion and auxiliary — for both pleasure and commercial vessels.
Model not listed? Call us on (03) 9399 5888 — we almost certainly cover it.
Common Caterpillar issues we diagnose & fix
Recognise any of these? They're the symptoms we're asked to look at most often on Caterpillar marine engines — from the electronic C7.1, C9.3, C12.9, C18 and C32 through to the legacy 3208, 3406 and 3412 — and diagnosing them is everyday work for us as an independent Cat marine specialist.
Overheating at cruise revs or under load
An engine that sits happily at idle but climbs once you push up to cruise usually points to the raw-water side — a tired impeller, blocked strainer or fouled heat exchanger. We flow-test and temperature-check the cooling system to find the actual restriction before it costs you a head gasket.
Black smoke and down on power
On hard-working marine Cats this is commonly a fouled aftercooler or turbocharger, worn injectors, or simple over-propping stopping the engine from reaching rated RPM. We measure boost and exhaust temperatures to pinpoint where the power is going and put it right.
Aftercooler fouling and corrosion
The seawater-cooled aftercooler cores fitted to many marine Cats are a known service item — they foul and corrode over time, robbing power and, left long enough, risking water being drawn into the engine. We clean, pressure-test and recondition or replace cores as part of scheduled servicing.
Raw-water pump leaks or impeller failure
A drip from the pump's weep hole means a seal is on the way out, and shredded impeller vanes often end up lodged downstream in the aftercooler or heat exchanger. We reseal or replace the pump and track down every missing vane.
Exhaust riser and manifold corrosion
Salt streaks or rust weeping around risers and elbows is worth taking seriously — internal corrosion can eventually let water back into the cylinders, which is how good engines get hydrolocked. We inspect, repair and replace marine exhaust components before they take the engine with them.
Recognise one of these? Call (03) 9399 5888 or book a diagnostic — we'll find the cause before it becomes a haul-out.
Our Caterpillar marine services
Caterpillar Servicing & Scheduled Maintenance
Routine servicing is the cheapest insurance a Cat marine engine can have, and our technicians service the range to manufacturer-recommended intervals. We work to the hours on your engine and the way you run your vessel, keeping logbooks current for survey and resale. Stay ahead of breakdowns with planned maintenance you can rely on — call (03) 9399 5888 to book a service.
- Oil, filter, fuel-filter and coolant servicing
- Cooling system, impeller, anode and heat-exchanger checks
- Valve clearance, belt and serpentine inspections
- Service logbooks maintained for survey and resale
Diagnostics & Fault-Finding
When a Caterpillar isn't running right, guesswork gets expensive. We troubleshoot symptom-first — overheating, hard starting, smoke, power loss, vibration — methodically testing the cooling, fuel-supply, air and exhaust systems to find the real cause. You get a clear explanation of what is wrong and a fixed quote before any work proceeds.
- Cooling system pressure, flow and temperature testing
- Fuel supply and filtration checks, from tank to lift pump
- Air intake, turbo boost and exhaust restriction checks
- Smoke, power-loss, overheating and vibration investigation
Repairs, Overhauls & Rebuilds
From a leaking water pump to a full ground-up rebuild, we carry out mechanical repairs across every Cat marine series. We handle top-end work, in-frame and full overhauls, and complete engine rebuilds — with machining, crack-testing and tolerancing done to spec. We'll always give you a straight assessment of repair versus rebuild versus repower so you spend money where it counts.
- Top-end, in-frame and full engine overhauls
- Turbocharger, injector, pump and injection repairs
- Cooling, exhaust, gasket and seal replacement
- Cylinder head, block and component machining
Parts, Repower & Installation Support
As an independent workshop we source genuine Caterpillar and quality aftermarket parts to suit your budget and how long you plan to keep the boat. When an old engine is beyond economical repair, we provide repower planning and installation support — including all-makes options where a like-for-like Cat replacement isn't the smart move. Talk to us before you commit, and we'll map the most cost-effective path.
- Source genuine Cat and quality aftermarket parts
- Filters, impellers, belts, gaskets and service kits
- Repower assessment, engineering and installation
- Alignment, gearbox and propulsion-system support
Mobile Service, Commercial & Survey Support
Not every job can come off the water, so we offer mobile service to vessels berthed across Port Phillip Bay and the Melbourne marinas. We support commercial operators with fleet servicing, breakdown response and the documentation needed for survey and insurance. Keep your boat earning with a workshop that understands commercial deadlines.
- Mobile service and breakdown call-outs across Port Phillip Bay
- Pre-purchase and insurance inspections with written reports
- Commercial fleet servicing and survey support
- Genset and auxiliary engine maintenance
Vessels & applications we look after
Get a Caterpillar service quote
Tell us your model and the issue — workshop or mobile across Port Phillip Bay, usually back to you in 1 business day.
Why boat owners choose Mariner
Caterpillar marine service — your questions answered
Do you service Caterpillar marine engines even though you're not a Cat dealer?
Yes. Mariner Engineering is an independent marine workshop, and our technicians service, diagnose, repair and rebuild Caterpillar marine diesels every week. We're not a factory Cat dealer, but we are experienced all-makes diesel specialists who know these engines inside out. You get expert work without dealer-level pricing — call (03) 9399 5888 for a quote.
Can you get genuine Caterpillar parts for my engine?
We source genuine Caterpillar parts as well as quality aftermarket equivalents, depending on your budget and plans for the vessel. For common service items and most repairs we can have parts to hand quickly. Tell us your engine model and serial number and we'll confirm availability and price — request a quote or call (03) 9399 5888.
Do you offer mobile service or do I have to bring the boat to you?
Both. We provide mobile service to vessels berthed across Port Phillip Bay and Melbourne's marinas, and we also carry out heavier work back at our Spotswood workshop. Larger overhauls and rebuilds are usually best done in the shop, but routine servicing and many repairs can be handled dockside. Call us and we'll work out the most practical option.
My Cat is old and tired — should I rebuild or replace it?
It depends on the engine's condition, hours, parts availability and how long you plan to keep the boat. Many older Cats like the 3208, 3406 and 3412 are well worth rebuilding because the cores are tough and parts are still available. We'll give you an honest assessment of rebuild versus repower, with costs, so you can make the right call. Get in touch on (03) 9399 5888 for a no-obligation appraisal.
How quickly can you turn my Caterpillar job around?
Routine servicing and minor repairs are often completed within a day or two, while overhauls and rebuilds depend on parts and machining lead times. We understand commercial vessels need to keep earning, so we prioritise breakdowns and give you a realistic timeframe up front. Call (03) 9399 5888 and we'll let you know where we can fit you in.
Request a Caterpillar service or repair quote
Tell us your Caterpillar engine model, your vessel and the service, fault or rebuild you need, and our team will get back to you with a quote — usually within 1 business day.
Mariner Engineering is an independent marine service and repair provider and is not an authorised dealer of, or affiliated with, Caterpillar. Caterpillar and associated model names are trademarks of their respective owners, used here only to describe the engines we service.