CAT 1H8278 SEAL for 345C Caterpillar Part - WSTPARTS
WSTPARTS supplies the 1H8278 SEAL, a CAT Thermostat replacement part designed for Caterpillar 345C, 3512 and G3508 applications. It is categorized under Thermostat. Every unit is fitment-verified before dispatch. Manual reference: 3406C: BASIC ENGINE, group 176-5818, page 211; 345C: HYDRAULIC SYSTEM, group 255-1811, page 405.
1H8278 SEAL for Caterpillar 345C — Genuine & OEM Replacement Part
WSTPARTS supplies genuine and high-quality OEM replacement SEAL (Part # 1H8278). Designed for CAT 345C, 3512, G3508, 3406C, 3516, 320C, 345D equipment.
Compatible Models
Key Features
- ✔ 100% compatible with CAT 345C, 3512, G3508, 3406C, 3516, 320C, 345D
- ✔ Meets Caterpillar original quality and performance standards
- ✔ Genuine CAT parts with anti-counterfeit label | OEM alternatives with warranty
- ✔ Available for order, contact for lead time
Specifications
| Part Number (MPN) | 1H8278 |
| Product Name | SEAL |
| Brand | CAT |
| Applicable Models | 345C, 3512, G3508, 3406C, 3516, 320C, 345D |
| Weight | 0.05 kg |
| Condition | New (Genuine / OEM Equivalent) |
| Warranty | 12 Months |
Where This Part Fits
Every row below is a real listing of 1H8278 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 | 176-5818 | p.211 |
| 345C | HYDRAULIC SYSTEM | 255-1811 | p.405 |
| 3512 | COOLING SYSTEM | 122-0501 | p.490 |
| 3516 | COOLING SYSTEM | 122-0500 | p.267 |
| G3508 | COOLING SYSTEM | 133-3689 | p.259 |
| 3512 | COOLING SYSTEM | 166-4377 | p.491 |
| 3516 | COOLING SYSTEM | 166-4378 | p.268 |
| G3508 | COOLING SYSTEM | 122-0501 | p.260 |
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.
System Notes — HYDRAULIC SYSTEM
The hydraulic system covers the main pump, control valves, cylinders, hydraulic tank, filters, hoses and all the fittings that connect them. It converts engine power into the pressure and flow that drive boom, bucket, steering and travel functions. Hydraulic parts fail mainly through contamination and heat: dirt that passes a worn breather scores pump components, aged hoses crack at the crimp, and O-rings harden and weep under pressure. A part in this group is normally replaced when a function drifts, a cylinder creeps, oil shows up under a machine that used to be dry, or the filter comes out loaded with metal.
FAQ
Is 1H8278 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 345C.
Genuine vs OEM replacement — what is the difference?
Genuine CAT parts carry an anti-counterfeit label. OEM equivalents are built to the same specifications, bench-tested and supplied with full warranty at a better price.
Stock, shipping and warranty?
Lead time confirmed on request; we quote the fastest available option. Every order is covered by a 12-month warranty.
📞 Get a Quote: Contact the WSTPARTS parts team | Email: cat@wstparts.com
