CATEngine Parts

4R9999 Excluder- Crankshaft Seal — Cat 120H 120H es

The CAT 4R9999 Excluder, also known as a crankshaft seal, is designed to prevent oil from leaking out of the engine crankcase along the crankshaft. It is made from durable elastomeric materials engineered to maintain a tight seal under varying temperatures and pressures, outperforming a cracked or hardened seal. Operators may notice oil spots under the equipment, a persistent smell of burning oil, or a drop in oil level when this seal begins to fail.

Excluder- Crankshaft Seal – Part No 4R9999 – CAT Spare Part
Part Specifications
BrandCAT
CategoryEngine Parts
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

const P = { partNo:'4R9999', name:'Excluder- Crankshaft Seal', brand:'CAT', brandSlug:'cat', category:'Engine Parts', catSlug:'engine-parts', condition:'OEM Aftermarket', description:'The CAT 4R9999 Excluder, also known as a crankshaft seal, is designed to prevent oil from leaking out of the engine crankcase along the crankshaft. It is made from durable elastomeric materials engineered to maintain a tight seal under varying temperatures and pressures, outperforming a cracked or hardened seal. Operators may notice oil spots under the equipment, a persistent smell of burning oil, or a drop in oil level when this seal begins to fail.', xref:['4R9999'], models:['120H','120H es','120H NA','12H','12M 2','12M 3','12M 3 AWD','135H','135H NA','140G','140M','140M 2','140M 3','140M 3 AWD','160M','160M 2'], specs:[{key:'Part No',val:'4R9999'},{key:'Brand',val:'CAT'},{key:'Category',val:'Engine Parts'},{key:'Condition',val:'Aftermarket — OEM Specification'},{key:'Dispatch',val:'Same-day from Mumbai (before 3 PM IST)'},{key:'GST Invoice',val:'Available — all orders'},{key:'Export Docs',val:'Commercial invoice, packing list, COO'}], relatedParts:[{"partNo": "5i-7668", "name": "Connecting Rod", "slug": "5i-7668"}, {"partNo": "319-3251", "name": "Speed Sensor", "slug": "319-3251"}, {"partNo": "316-7986-324-6498", "name": "Fuel Injection Pump", "slug": "316-7986-324-6498"}, {"partNo": "3779352", "name": "Hydraulic Cylinder Seal Kit", "slug": "3779352"}, {"partNo": "CTP7e4729-iK", "name": "Inframe Engine Kit", "slug": "CTP7e4729-iK"}, {"partNo": "239-4385", "name": "Front Idler Assembly", "slug": "239-4385"}], reviews:[{name:'Vikram Singh',loc:'Delhi, India',rating:5,text:'CAT part arrived fast. OEM specification, fits perfectly in my 320D. Highly recommend PTC.'},{name:'Ibrahim Al Rashid',loc:'Dubai, UAE',rating:5,text:'Great service and fast shipping to UAE. The CAT part was exactly as described. Very reliable supplier.'},{name:'Pradeep Sharma',loc:'Nagpur, Maharashtra, India',rating:4,text:'Quick response, good quality. Team confirmed compatibility before dispatch which I appreciated.'}], faq:[{q:'What is the primary purpose of the crankshaft excluder seal?',a:'The excluder seal prevents engine oil from escaping the crankcase where the crankshaft exits the engine block.'},{q:'Will part 4R9999 fit my CAT 120H ES machine?',a:'Yes, part number 4R9999 is listed for compatibility with CAT 120H ES models. Always cross-reference with your machine\'s serial number for confirmation.'},{q:'How does this aftermarket seal compare to the original CAT seal?',a:'This seal is manufactured to meet OEM specifications, ensuring equivalent sealing performance and durability for your engine.'},{q:'What is the typical cause of crankshaft seal failure?',a:'Failure is often due to age, heat, and wear, leading to hardening, cracking, or loss of elasticity in the sealing material.'}], categoryDesc:'CAT Engine Parts from Parts Trading Company cover the full range of CAT equipment. We supply OEM-specification aftermarket engine parts sourced from certified manufacturers. PTC has supplied CAT engine parts to customers across India, UAE, Russia, Indonesia, and Africa since 1956. Our Mumbai warehouse stocks high-turnover CAT engine parts for same-day dispatch before 3 PM IST.', aiSpecs:[{"key": "Part Type", "val": "Crankshaft Seal (Excluder)"}, {"key": "Material", "val": "NBR Rubber"}, {"key": "Application", "val": "Engine Crankshaft Seal"}, {"key": "Service Life", "val": "Replace based on inspection or during engine rebuild"}, {"key": "Compatibility", "val": "CAT 120H, 120H ES, 120H NA, 12H, 12M 2"}, {"key": "Condition", "val": "New \u2014 OEM specification"}],};script src="/assets/js/product-page.js">

Related CAT Parts

From the same category — may also be needed

5i-7668
Connecting Rod
319-3251
Speed Sensor
316-7986-324-6498
Fuel Injection Pump
3779352
Hydraulic Cylinder Seal Kit
CTP7e4729-iK
Inframe Engine Kit
239-4385
Front Idler Assembly

Browse all CAT Engine Parts →

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Installation & Application Notes

Inspect mating surfaces for wear before fitting. Use torque specs from service manual. Replace gaskets and seals as a set — reusing compressed gaskets causes oil leaks. Clean all oil passages with compressed air.

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

Part TypeCrankshaft Seal (Excluder)
MaterialNBR Rubber
ApplicationEngine Crankshaft Seal
Service LifeReplace based on inspection or during engine rebuild
CompatibilityCAT 120H, 120H ES, 120H NA, 12H, 12M 2
ConditionNew — OEM specification

Failure Symptoms

The most common symptom of a failing crankshaft seal is visible oil leakage around the crankshaft pulley. If left unaddressed, the oil leak can worsen, leading to a significant loss of engine oil. This can compromise engine lubrication and potentially cause internal engine damage.

Installation Tip

Carefully inspect the crankshaft surface where the seal rides for any nicks or damage that could cause a new seal to leak immediately. Use a proper seal driver to ensure the seal is installed straight and at the correct depth.

Service Note

Inspect the crankshaft for wear or damage and clean the sealing surface thoroughly before installing the new seal.