Description
About This Engine
The Caterpillar 3046 is an inline-six direct-injection diesel engine used in Caterpillar's medium-duty excavator and crawler dozer products from the early 1990s through the mid-2000s. Built under Caterpillar's manufacturing agreement with Mitsubishi- an arrangement that dates to the 1980s- the 3046 is produced with shared CAT-Mitsubishi engineering standards. Parts for this engine carry both Caterpillar and Mitsubishi part numbers, and buyers sourcing components should be aware that searching under either brand designation may yield the same or compatible parts.
The 3046 family includes two aspiration configurations: the naturally aspirated base version and the 3046T turbocharged variant. The 3046T was used in the CAT 315C excavator where Caterpillar specifically noted it as having the best fuel consumption in its class among diesel engines- a result of improved thermal efficiency and reduced friction between the piston and liners. Both variants share the same fundamental cast iron block-and-head construction with wet-sleeve cylinder liners.
The wet-sleeve liner design is the 3046's most important practical advantage. Unlike parent-bore engines where the cylinder walls are part of the block and require expensive boring or line-honing to rebuild, the 3046's liners are removable sleeves that can be replaced individually. This significantly reduces rebuild cost and time, particularly for operators in remote locations or those doing in-frame overhauls without access to full machine shop capabilities.
Signs You Need a Replacement Engine
- Excessive black smoke under load- injector wear, injection timing drift, or turbocharger issues (3046T)
- White smoke on cold start that does not clear- cylinder liner wear allowing oil into combustion, or injector tip carbonization
- Loss of power without obvious external cause- injection pump delivery rate reduction or air restriction
- Overheating- cooling system restriction or water pump failure. Overheating accelerates liner and seal wear.
- Oil in coolant or coolant in oil- liner seal (O-ring at wet-sleeve base) failure- a common wear item on aged 3046 engines
- Fuel consumption increase without corresponding power gain- injector spray pattern degradation on high-hour units
Known Problems With This Engine
- Wet-sleeve liner O-ring seal leakage- the 3046's most common age-related concern: Each wet-sleeve liner sits in the block on O-ring seals at the base. These seals can harden and leak with age and heat cycling, allowing coolant and oil to mix. We inspect coolant condition and oil for contamination before shipping. O-ring replacement at liner replacement is the correct service.
- Injection pump delivery rate reduction: The mechanical injection pump on high-hour 3046 engines develops wear that reduces fuel delivery rate and injection pressure. Symptoms are power loss and increased fuel consumption. The pump is a serviceable component requiring diesel injection specialist equipment.
- Turbocharger oil seal wear (3046T): The turbocharger on 3046T applications can develop bearing wear and oil seal leakage on high-hour units, causing blue smoke and oil consumption. We note turbocharger condition where applicable before shipping.
- Valve lash drift: The 3046 requires periodic valve lash adjustment. Valve lash on inlet and exhaust is 0.25 mm (approximately 0.010 in) for both. Neglected valve lash causes rough running and reduced performance. We inspect valve train condition before shipping.
- Parts dual-numbering confusion: Buyers ordering replacement parts for the 3046 should be aware that parts are listed under both CAT and Mitsubishi numbers. Using the machine serial number and the engine serial number (5XK prefix most common) is the most reliable way to source correct components.
Caterpillar 3046 Variants
Two aspiration configurations with largely shared internal architecture:
| Variant | HP Range | Key Applications and Notes |
|---|---|---|
| 3046 (Naturally Aspirated) | 100 to 120 hp | CAT 933C/933 track loader | CAT D3C LGP/XL dozer | CAT D4C LGP/XL dozer | Some early 300-series excavators. No turbocharger. |
| 3046T (Turbocharged) | 130 to 190 hp | CAT 315C excavator (noted best fuel consumption in class) | CAT 315BL | CAT 320 series some applications | More common in later production machines. |
What Is Included- What Is Not Included
| INCLUDED- Long Block | Cast iron block with wet-sleeve cylinder liners, crankshaft, pistons, connecting rods, camshaft, cast iron cylinder head, valve train, oil pan, front timing cover. |
|---|---|
| Turbocharger | 3046T units- turbocharger may or may not be present. Confirm at order. |
| NOT INCLUDED | Injection pump (confirm- may or may not be present on the unit), injectors, exhaust manifold, air intake system, alternator, starter, hydraulic pump drive (on excavator applications), flywheel. |
| Serial Number | Engine serial number (5XK prefix most common) documented before shipping- essential for parts sourcing. |
| Core Note | No core charge. |
Vehicle Compatibility
The Caterpillar 3046 and 3046T were used in the following equipment:
| CAT 315C Excavator | 3046T- turbocharged. Best-in-class fuel consumption noted by Caterpillar. |
|---|---|
| CAT 315BL Excavator | 3046T- turbocharged variant |
| CAT 320 Series Excavators (select applications) | 3046T- some early 320 series applications |
| CAT 933C and 933 Track Loader | 3046 naturally aspirated |
| CAT D3C Crawler Dozer (XL and LGP) | 3046 naturally aspirated |
| CAT D4C Crawler Dozer (XL and LGP) | 3046 naturally aspirated |
The 3046 uses Caterpillar's standard equipment mounting architecture for this class. Replacement should be like-for-like using matching serial prefix units. Confirm your machine's engine serial number before ordering to ensure correct configuration.
Engine or transmission: Caterpillar hydraulic transmission systems- application specific. The 3046 is coupled to hydraulic torque converters and powershift transmissions depending on the equipment application. Confirm your machine's specific drivetrain before ordering.
Not sure if this fits? Call (240) 301-0095. We verify fitment before every order ships.
Common Names and Search Terms
| CAT 3046 | Most common buyer search |
|---|---|
| Caterpillar 3046 | Full designation |
| 3046T | Turbocharged variant |
| CAT 315 engine | Application buyer |
| CAT 320 engine | Application buyer |
| CAT dozer engine | Dozer application buyer |
| CAT excavator engine | Excavator buyer |
| CAT 3046 diesel | Fuel type designation |
| Mitsubishi 3046 | Manufacturing origin buyer |
| CAT 3046 5XK | Serial prefix buyer |
Used OEM vs Rebuilt- Which Is Right for You?
Used OEM is the right choice for equipment operators who need a cost-effective tested engine with documented serial number and variant confirmed. Our 3046 units are inspected with liner condition, coolant contamination, and turbocharger condition (3046T) assessed before shipping.
A rebuilt 3046 from a CAT-certified rebuilder or authorized CAT Reman exchange makes sense for machines requiring fresh liner seals, new injection components, and full warranty coverage. CAT Reman pricing is typically $4,000 to $9,000 or more. Call us and we can discuss current unit condition.
Condition and Inspection Process
- Full external inspection- block, head, liner protrusion area, coolant hose connections, and all accessible surfaces
- Natural vs turbocharged variant confirmed- 3046 or 3046T documented before every order
- Engine serial number documented- 5XK or other prefix recorded for parts sourcing
- Coolant inspected for oil contamination- wet-sleeve liner O-ring failure indicator
- Oil inspected for coolant contamination
- Valve cover removed where accessible for valve train inspection
- Turbocharger condition noted on 3046T units- oil seepage and shaft play assessed
Mileage and operating hours vary by unit. Where available from the donor vehicle or equipment, we provide this information. Where it cannot be confirmed, we disclose this before your order is placed.
Buyer Tips- What to Know Before You Order
- Document the engine serial number: The 5XK serial prefix (most common) and full serial number are essential for ordering correct replacement parts. CAT and Mitsubishi part numbers may differ- the serial number is the authoritative reference. We document this before shipping.
- Machine serial number for parts ordering: In addition to the engine serial number, the machine serial number (e.g., 315C serial number) is often needed for ordering application-specific components like injection pump arrangements and accessory drives.
- Wet-sleeve liner service: If performing an overhaul on a used 3046, replace all liner O-ring seals at installation regardless of apparent condition. O-ring seal kits are inexpensive- coolant-oil contamination from a failed O-ring is expensive to address after the fact.
- Oil specification: CAT ECF-1 specification or equivalent API CI-4 or higher diesel engine oil SAE 15W-40. Change every 250 operating hours. The 3046 is oil-quality sensitive at the valve train and injection pump.
- Valve lash at installation: Check and adjust valve lash at installation on any used 3046. Inlet and exhaust specification is approximately 0.25 mm (0.010 in) cold.
Why Buy From Vaz Auto Solutions
- 3046 vs 3046T variant confirmed- turbocharged vs naturally aspirated documented before you pay
- Engine serial number documented- 5XK or other prefix recorded for parts sourcing
- Coolant contamination assessed- wet-sleeve liner O-ring failure detected
- Turbocharger condition noted on 3046T units
- Wet-sleeve liner condition assessed- 3046's key rebuildability advantage
- No core charge- keep your old engine
- Free specialist freight carrier delivery to all 50 states
- 15 day replacement warranty on internal defects
- Call (240) 301-0095- speak with someone who understands CAT 3046 variants and equipment engine sourcing
Christopher Martinez (verified owner) –
Excellent used 3046 engine. Dropped right into my Cat loader. Running smooth for weeks now. Great find
James Wilson (verified owner) –
Reliable Cat 3046 from Find Auto Parts Online. Strong performance in my excavator. Quick shipping, competitive price.
Tom K., Phoenix AZ –
Needed a 3046T for my 315C after high hours finally caught up with the original. Vaz confirmed the turbocharged 3046T variant and documented the 5XK serial before shipping. Coolant inspected clean — no liner O-ring contamination. Turbocharger oil seal on the replacement checked good. Machine back in service within the week.
Brad M., Denver CO –
Replaced the naturally aspirated 3046 in my D4C. Vaz confirmed the NA variant and serial number before I bought. Minor valve cover oil seep disclosed — fixed at installation. Engine runs strong. Good to deal with people who know the 3046 is Mitsubishi-based and understand the dual part numbering.