CAT 0303978 CONNECTOR for C18 Caterpillar Part - WSTPARTS
WSTPARTS supplies the 0303978 CONNECTOR, a CAT Electrical System replacement part designed for Caterpillar C18, 3516B and 3512 applications. It is categorized under Electrical System. Every unit is fitment-verified before dispatch. Manual reference: 3512: COOLING SYSTEM, group 231-6339, page 555; 3516B: COOLING SYSTEM, group 197-9064, page 233.
0303978 CONNECTOR for Caterpillar C18 — Genuine CAT & Replacement Part
WSTPARTS supplies genuine CAT and OEM-equivalent direct-replacement CONNECTOR (Part # 0303978). Designed for CAT C18, 3516B, 3512, 3306, C32 equipment.
Compatible Models
Key Features
- ✔ 100% compatible with CAT C18, 3516B, 3512, 3306, C32
- ✔ Meets Caterpillar original quality and performance standards
- ✔ Genuine CAT lines: New Genuine / Cat Reman / Cat Classic | OEM-equivalent direct replacements
- ✔ In stock, ready to ship
Specifications
| Part Number (MPN) | 0303978 |
| Product Name | CONNECTOR |
| Brand | CAT |
| Applicable Models | C18, 3516B, 3512, 3306, C32 |
| Weight | 0.05 kg |
| Condition | New (Genuine CAT / OEM-equivalent direct replacement) |
| Warranty | 12 Months |
Where This Part Fits
Every row below is a real listing of 0303978 in the Caterpillar parts manual: the machine it is published under, the system it belongs to, the group number and the manual page. Use it to confirm the part against your own parts book before ordering.
| Machine | System | Group No. | Manual Page |
| 3512 | COOLING SYSTEM | 231-6339 | p.555 |
| 3516B | COOLING SYSTEM | 197-9064 | p.233 |
| C18 | ELECTRICAL AND STARTING SYSTEM | 241-2422 | p.322 |
| C32 | COOLING SYSTEM | 355-8823 | p.162 |
| 3306 | FUEL SYSTEM | 150-3730 | p.896 |
| C32 | COOLING SYSTEM | 355-8834 | p.163 |
| 3516B | COOLING SYSTEM | 208-0822 | p.239 |
| C32 | COOLING SYSTEM | 419-4106 | p.164 |
System Notes — COOLING SYSTEM
The cooling system covers the radiator, water pump, thermostat, fan and fan drive, coolant hoses, clamps, the surge tank and the belts that drive it. It holds engine temperature inside the range where clearances and oil film stay correct. Failures are usually slow and then sudden: a hose softens and balloons before it bursts, a water pump seal starts weeping from the weep hole, a thermostat sticks partly open so the engine runs cold and burns more fuel. On construction sites the radiator also packs with dust and debris, which raises pressure across the core and finds the weakest hose or clamp first.
System Notes — ELECTRICAL AND STARTING SYSTEM
The electrical and starting system covers the battery, starter motor, alternator, wiring harness, relays, switches and the instrument panel. It carries current from the batteries to the starter to crank the engine, and from the alternator back to keep the batteries charged. Because these machines work in dust, vibration and wide temperature swings, connectors corrode, harness insulation chafes against the frame, and starter solenoids burn out from repeated short cranks. Parts in this group are usually replaced on a symptom basis — slow cranking, a dash warning, lights that dim under load, or a no-start condition traced to an open circuit.
FAQ
Is 0303978 the right part for my machine?
Match the part number on your old part, or send us your equipment serial number — WSTPARTS verifies fitment free of charge for CAT C18.
Genuine CAT vs direct replacement — what is the difference?
Genuine CAT covers three factory lines: New Genuine, Cat Reman (core exchange with core charge) and Cat Classic (brand-new economy line). OEM-equivalent direct replacements are non-CAT parts; grade and warranty are confirmed in the quotation.
Stock, shipping and warranty?
In stock — ships within 24 hours. Every order is covered by a warranty per quotation.
📞 Get a Quote: Contact the WSTPARTS parts team | Email: cat@wstparts.com
