Fuel Injector 557-7633 20R-8064 for Caterpillar CAT Engine C9 C9.3 C-9
This fuel injector is engineered as a direct replacement for the Caterpillar CAT Engine C9 C9.3 C-9. Manufactured to meet or exceed OEM specifications, it delivers reliable performance in demanding conditions. Each unit is tested for fuel flow, pressure rating, and durability before leaving the factory to ensure consistent quality across every order.
Vehicle Compatibility
| Application | Details |
|---|---|
| Caterpillar | See product specifications |
| CAT Engine:C9, C9.3, C | 9 Applications:Fit For |
| CAT Motor Grader:140M, 140M Series 2, 14L, 160M, 160M Series 2Fit For | See product specifications |
| CAT Track Feller Buncher:2390, 2491Fit For | See product specifications |
| CAT Excavator:330D, 330D L, 330D N, 336D, 336D L, 336D LN, 336D2, 336D2 L, 336D2 GC, 336D2 XE, 336D2 LXE, 340D2 LFit For | See product specifications |
| CAT Wheel Dozer:814F Series 2, 815F Series 2, 816F Series 2Fit For | See product specifications |
| CAT Wheel Scraper:627G | See product specifications |
Replaces OEM Part Numbers
CA5577633 • 557-7633 • 5577633 • 20R-8064 • CA20R8064 • 20R8064 • 20R-8968 • 20R8968 • CA20R8968 • Caterpillar • Engine
Signs You Need a Replacement
If your equipment is showing any of these symptoms, the injectors & nozzle may be the cause:
- Rough idle or misfire — Uneven fuel delivery from a worn injector causes the engine to shake at idle. On Caterpillar engines, this is often accompanied by a knocking sound under load.
- Black or white exhaust smoke — Black smoke means excess fuel; white smoke indicates incomplete combustion. Both point to injector spray pattern degradation.
- Loss of engine power — A single failing injector reduces cylinder output. Multi-cylinder engines lose noticeable power when one injector flows less than the rest.
- Increased fuel consumption — Poor atomization means the engine burns more fuel to produce the same power. Monitor your fuel burn rate as an early warning sign.
- Hard starting or no start — If the injector doesn’t deliver fuel on cranking, the cylinder won’t fire. This is especially common in cold weather with worn nozzles.
- Fuel in engine oil (dilution) — Fuel leaking past the injector seat seal contaminates the crankcase oil. If the oil level rises or smells of diesel, inspect the injectors immediately.
Replace as a Set
Replace all injectors as a set whenever possible. On Caterpillar engines, mixing old and new injectors creates uneven fuel delivery — the new injectors compensate for the worn ones, shortening their life. When installing, use new copper sealing washers and torque to the specification in the service manual. After installation, run the engine at idle for 5 minutes to bleed air from the fuel system, then check for leaks at each injector connection before putting the machine under load.
Frequently Asked Questions
Which Caterpillar models does this part fit?
Refer to the Vehicle Compatibility table above for the full list of Caterpillar models. Each listing includes the body type, engine, and production years. Match your vehicle’s engine code (stamped on the engine block) against the listed codes to confirm.
Can I cross-reference CA5577633 with 557-7633?
Yes. Both CA5577633 and 557-7633 are interchangeable OEM numbers for this part. They refer to the same component with the same specifications, just different part number revisions.
What are the common failure signs on a Caterpillar engine?
On Caterpillar engines, watch for black exhaust smoke under load, rough idle, misfire codes (P0300 series), and loss of power. A single failing injector can reduce engine output by up to 25%. If you notice fuel in the engine oil, the injector seat seal is likely compromised.
What tools do I need to install this on a Caterpillar?
Standard metric hand tools will handle most of the job – sockets, wrenches, and a torque wrench. For Caterpillar equipment, check the specific service manual for any special tools or torque values.
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