CAT 4N3661 CHECK NPR for C18 Caterpillar Part - WSTPARTS
Need a dependable Engine System part for your Caterpillar C18, C15 and 3406C machine? The 4N3661 CHECK NPR from WSTPARTS is manufactured to OEM-grade tolerances. It is categorized under Engine System. Every unit is fitment-verified before dispatch. Manual reference: 3406C: BASIC ENGINE, group 206-7331, page 343; 3406E: BASIC ENGINE, group 126-9140, page 187.
4N3661 CHECK NPR for Caterpillar C18 — Genuine CAT & Replacement Part
WSTPARTS supplies genuine CAT and OEM-equivalent direct-replacement CHECK NPR (Part # 4N3661). Designed for CAT C18, C15, 3406C, 3406E equipment.
Compatible Models
Key Features
- ✔ 100% compatible with CAT C18, C15, 3406C, 3406E
- ✔ Meets Caterpillar original quality and performance standards
- ✔ Genuine CAT lines: New Genuine / Cat Reman / Cat Classic | OEM-equivalent direct replacements
- ✔ Available for order, contact for lead time
Specifications
| Part Number (MPN) | 4N3661 |
| Product Name | CHECK NPR |
| Brand | CAT |
| Applicable Models | C18, C15, 3406C, 3406E |
| Weight | 0.41 kg |
| Condition | New (Genuine CAT / OEM-equivalent direct replacement) |
| Warranty | 12 Months |
Where This Part Fits
Every row below is a real listing of 4N3661 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 |
| 3406C | BASIC ENGINE | 206-7331 | p.343 |
| 3406E | BASIC ENGINE | 126-9140 | p.187 |
| C15 | BASIC ENGINE | 061-9458 | p.403 |
| C18 | BASIC ENGINE | 061-9458 | p.240 |
| C15 | BASIC ENGINE | 105-3386 | p.404 |
| C18 | BASIC ENGINE | 105-3386 | p.241 |
| C18 | BASIC ENGINE | 109-3285 | p.243 |
| C15 | BASIC ENGINE | 109-3285 | p.406 |
System Notes — BASIC ENGINE
The basic engine group covers the core structure and internals: cylinder block, cylinder head, pistons, rings, liners, connecting rods, crankshaft, bearings, camshaft and the gasket sets that seal them. These parts determine compression, oil pressure and power output. They wear gradually — rings lose tension, bearings show copper, liners glaze — and the first signs are usually blow-by from the breather, rising oil consumption, or a knock that gets louder as the engine warms. Replacing a basic engine part is a planned overhaul decision rather than a roadside fix, so matching the exact part number and serial number range matters more here than anywhere else on the machine.
FAQ
Is 4N3661 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?
Lead time confirmed on request; we quote the fastest available option. Every order is covered by a warranty per quotation.
📞 Get a Quote: Contact the WSTPARTS parts team | Email: cat@wstparts.com
