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Bitzer 4NFCY Rebuilt Bus AC Compressor — New vs Renewed: The Cost Decision
Decision support document DS-4NFCY-R | For fleet operators, bus workshops and parts distributors choosing between new-OEM and professionally rebuilt 4NFCY compressors.
- Overview
- Recommended Products
1. The Decision Framework
The Bitzer 4NFCY is one of the highest-volume bus AC compressor cores in global circulation, fitted on 7–13.5 m buses from Yutong, King Long, Higer, Zhongtong, Foton, BYD, Volvo, Mercedes-Benz and Hyundai. When a core fails, the buyer faces three paths: new OEM unit, generic reman, or professionally rebuilt core. This document compares them on the numbers that matter: cost, testing, warranty and delivery.
Decision factor |
New OEM |
Generic reman |
Our renewed 4NFCY |
Purchase cost |
100% (baseline) |
Variable quality |
40–60% below new OEM |
Refurbishment |
— |
Partial — failed parts only |
Full disassembly + 9-step process |
Testing |
Factory certified |
Visual check only |
100% test-bench run |
Worn parts |
New |
May reuse damaged |
All replaced with new OEM-grade |
Warranty |
OEM terms |
3–6 months |
12 months |
Lead time |
Long |
Uncertain |
7 days ready to ship |
Documentation |
Full |
None |
Test report + refurbishment certificate |
2. What 'Renewed' Means Here — The 9-Step Process
A renewed core is only as good as its process. Every Weili-rebuilt 4NFCY follows the same documented 9-step line:
Step |
Process |
What is verified |
1 |
Incoming inspection |
Visual + initial performance test |
2 |
Complete disassembly |
Full teardown to components |
3 |
Component cleaning |
Ultrasonic cleaning |
4 |
Wear inspection |
Cylinders, pistons, bearings vs OEM specs |
5 |
Parts replacement |
New OEM-grade seals, gaskets, bearings, valves |
6 |
Reassembly |
Standardized torque settings |
7 |
Leak testing |
Nitrogen pressure — zero leak tolerance |
8 |
Performance testing |
Test bench: capacity + clutch engagement |
9 |
Final inspection |
Vibration, noise, oil flow |
Fig. 1 — Rebuilt Bitzer 4NFCY compressor, ready for dispatch
Fig. 2 — Compressor body detail: 4-cylinder open-type configuration, belt-driven
3. Technical Data Sheet
Model |
4NFCY (Renewed) |
Type |
4-cylinder open-type reciprocating |
Cylinder volume |
647 cm³ (39.4 CIR) |
Displacement @ 1450 rpm |
56.2 m³/h (1986 CFH) |
Displacement @ 3000 rpm |
116.4 m³/h (4110 CFH) |
Cylinders × bore × stroke |
4 × 70 × 42 mm |
Allowed speed range |
500 – 3500 rpm |
Weight (without clutch) |
33.0 kg (73.0 lb) |
Magnetic clutch |
LA16 — 12V or 24V DC (10 kg) |
V-belts |
2 × SPB |
Max. pressure (LP/HP) |
19 / 28 bar |
Refrigerant / oil |
R134a: BSE 55 (opt.) · R22: B5.2 (std.) |
Oil charge |
2.5 dm³ |
Crankcase heater |
70 W 12/24V DC (option) |
Capacity control |
100–50% (option) |
Fig. 3 — Shaft and clutch interface: LA16 electromagnetic clutch (12V/24V) with 2×SPB belt drive
4. Application Coverage
The 4NFCY serves urban public transport buses, tourist coaches, intercity passenger buses, school buses and double-deck buses from 7 to 13.5 m. Anti-vibration construction suits bumpy roads and extreme temperature changes; the compressor is designed for mobile air conditioning only — not stationary refrigeration, chillers or passenger-car AC.
Application |
Vehicle length |
Notes |
Urban public transport |
7–13.5 m |
High-idle duty cycle |
Tourist coaches |
8–13.5 m |
Long-distance highway |
Intercity passenger |
7–12 m |
Mixed duty |
School buses |
7–10 m |
Stop-and-go |
Double-deck buses |
10–13.5 m |
High thermal load |
Fig. 4 — Rebuild line: professional reassembly with standardized torque and sealing procedures
5. Risk Control — 100% Tested Before Shipment
Test |
Standard |
Leak test |
Nitrogen pressure — no drop over 30 min |
Clutch engagement |
12V/24V function check |
Running test |
30 min on test bench, variable speeds |
Cooling capacity |
Verified against OEM spec range |
Vibration test |
Within bus-installation limits |
Oil flow |
Proper lubrication confirmed |
Every unit ships with a test report and refurbishment certificate, batch traceability label, and 12-month warranty. Monthly processing capacity: 200+ rebuilt compressors; 100+ units of 4NFCY held in stock for 7-day dispatch.
Fig. 5 — Replacement shaft seal for 4NFCY (available as spare part for rebuild programs)
6. Buyer FAQ
Q1. How much can I save versus a new OEM compressor?
Our renewed 4NFCY typically costs 40–60% less than a new OEM unit while restoring OEM performance — with a 12-month warranty instead of the 3–6 months common on generic remans.
Q2. Is the rebuilt compressor tested before shipping?
Yes, 100% of units: nitrogen leak test, clutch function check, 30-minute variable-speed bench run, cooling capacity verification, vibration and oil-flow checks.
Q3. What is included with each unit?
The rebuilt compressor, a test report, refurbishment certificate, and batch traceability label. Clutch (LA16) and crankcase heater are available as options.
Q4. Which refrigerants and oils are supported?
R134a with BSE 55 oil (option) and R22 with B5.2 oil (standard); oil charge 2.5 dm³.
Q5. What buses is it for?
7–13.5 m buses — Yutong, King Long, Higer, Zhongtong, Foton, BYD, Volvo, Mercedes-Benz, Hyundai and similar platforms with 4NFCY fitment.
Q6. How fast can you ship?
7 days against order confirmation; 100+ units held in stock for global dispatch.
Contact Our Export Team
Hunan Weili Auto Parts Appliance Co., Ltd. — founded in 2007, ISO 9001 & IATF 16949 certified manufacturer of bus & truck AC parts, electric fans, blowers, lighting and alternator components.
WhatsApp / WeChat: +86-18670382782 | Landline: +86-0731-82034997 / 82034998
E-Mail: [email protected] | Websites: www.weilipart.com | www.weiliautomotive.com | www.cooliparts.com
Send us your OEM part number, vehicle model or drawing — we will reply within 24 hours with a quotation and technical data sheet.
