CATFuel System

277-4837 Water Expansion Tank — Cat 120K 120M

This is a Caterpillar Water Expansion Tank, also known as an overflow or surge tank, for the engine cooling system. It is designed to maintain proper coolant levels and pressure within the system, preventing overheating and cavitation. A failing tank may show signs of swelling, cracking, or leakage, leading to coolant loss and potential engine damage.

Water Expansion Tank – Part No 277-4837 – CAT Spare Part
Part Specifications
BrandCAT
CategoryFuel System
ConditionAftermarket — OEM Specification
DispatchSame-day from Mumbai (before 3 PM IST)
GST InvoiceAvailable — all orders
Export DocsCommercial invoice, packing list, COO

Compatible Models

Always verify with serial number before ordering.

WhatsApp for Price & Availability☎ Call Mumbai Office

Parts Trading Company  ·  Mumbai, Est. 1956  ·  Same-day dispatch  ·  Ships worldwide  ·  GST invoice included

;

Related CAT Parts

From the same category — may also be needed

7N0449
Nozzle As
7Y3913
Motor As
8P0408
Cap-Fuel Tank Filler
1307282
Bracket
1329447
Pump As-Fuel Transfer
2475213
Actuator As-Governor

Browse all CAT Fuel System →

Ship This Part To Your Location

DubaiSaudi ArabiaNigeriaKenyaSouth AfricaBangladeshMalaysiaGhanaQatarEgypt
India
MaharashtraGujaratTamil NaduRajasthanKarnatakaTelangana

Full shipping information on regional pages · Air freight 2–12 days · GST invoice for India

Installation & Application Notes

Use clean, filtered fuel — fuel injection components have micron-level tolerances. Prime fuel system before cranking to avoid dry-start damage. Replace fuel filter whenever servicing injection components. Calibrate injectors after replacement if equipment has ECU.

Always consult the OEM service manual for model-specific torque values and procedures. WhatsApp our technical team if you need fitment guidance.

Part TypeWater Expansion Tank
MaterialHigh-density polyethylene
ApplicationEngine cooling system
Service LifeReplace when signs of degradation appear
CompatibilityOEM specification
ConditionNew — OEM specification aftermarket

Failure Symptoms

The first sign of a failing expansion tank is often visible coolant loss or a persistent low coolant warning. If ignored, the system may lose its ability to maintain proper pressure, leading to overheating and reduced engine performance. Continued operation with a compromised cooling system can result in severe engine damage.

Installation Tip

Ensure the cooling system is completely cool before draining and removing the old tank to avoid burns. Do not overtighten the mounting bolts, as this can crack the plastic tank.

Service Note

Inspect all coolant hoses and clamps for signs of wear, cracking, or leaks when replacing the expansion tank.