This is a 100% BRAND NEW genuine PTTURBO.COM RHF4 Turbocharger — a direct bolt-on replacement designed for 2.2L diesel engines in Caterpillar, Perkins, New Holland, and Shibaura industrial equipment.

This precision-built turbo comes complete with all installation gaskets and is engineered to deliver OEM-level fitment and performance. Ideal for restoring power, torque, and reliability in skid steers, track loaders, tractors, and generator sets.

Turbo Specifications:

• Model: RHF4 / RHF4-46001P8.5NHBRL323CAZ
• Short Spec: AS12
• Turbine Housing A/R: 8.5
• Displacement: 2.2L (2200cc), 4 Cylinder
• Fuel Type: Diesel
• CHRA: NZ870564

Included Gaskets:

• Oil Inlet Gasket: 210393
• Oil Outlet Gasket: 210636
• Turbine Inlet Gasket: 210385 (2258533)

Repair Kit: NH449813

OEM / Interchange Part Numbers:

• OEM #: 0104-890-012, 13575-6180, 238-9349, 2390230, 2825179, 3082308, 3170981, 3240237, 4429826, 4T-506
• Interchange #: F41CAD-S0081B, F41CAD-S0081G, VA420081, VA420057
• Part #: VB420081

Compatible Engine Models:

• N844L / N844LT
• 3024 / 3024C
• C2.2 / C2.2T
• 404C-22T / 404D-22

Application Fitment:

• Caterpillar 247 Series Skid Steers, Track Loaders, Industrial Applications
• Caterpillar Multi-Terrain Loaders: 247B, 247B2, 257B, 257B2
• Caterpillar Marine & Generator Sets with C2.2 Engines
• New Holland TC55DA Tractors (with Perkins 404C-22T / 404D-22)
• Shibaura ST445 Tractors (with N844L / N844LT engines)
• Terex Loaders and other equipment using RHF4 turbo platform

Why Choose This Turbo?

• 100% brand new — no core charge, no remanufactured parts
• All installation gaskets included for a seamless swap
• Restores lost performance and fuel efficiency
• Precision balanced and built to OEM spec

Fitment Tip:
To ensure exact compatibility, match the turbo part number from your original unit’s nameplate. If you’re unsure, contact us — we’re happy to help verify before purchase.

California buyers: Sales tax applies
We respond to emails during business hours (Mon–Fri, Pacific Time). Closed on weekends and holidays.

About This RHF4 Turbocharger — Caterpillar / Shibaura Tractor ST445

The IHI RHF4 is a compact turbocharger used in agricultural and light industrial diesel engine applications including the Caterpillar and Shibaura ST445 tractor diesel engine. Part numbers VA-420081 and AS12 identify this specific unit. The RHF4 platform is known for reliability in steady-state load conditions typical of agricultural equipment, but failure still occurs from oil contamination, extended service intervals, or ingestion of debris through compromised air filtration systems — a common occurrence in field conditions.

This replacement RHF4 is built to the specifications for the ST445 diesel application and is a direct replacement for the original failed unit. Verify your existing part number before ordering to confirm fitment, as the RHF4 platform is used across several applications with slightly different specifications.

Common RHF4 Failure Causes in Agricultural Use

• Air filter neglect — field dust accelerates compressor wheel erosion
• Extended oil change intervals — journal bearings are the first wear point
• Hot shutdown without idle-down — heat soak bakes oil in the bearing housing
• Oil starvation during low-oil-level operation

Installation Recommendations

Before installing this replacement turbocharger, flush the engine oil system and install new oil and filter. Inspect the oil feed line to the turbo for restriction — carbon deposits in the banjo fitting are a common issue on high-hour agricultural engines. Pre-fill the bearing housing with fresh oil before startup. PT Turbo in San Bernardino, CA has been rebuilding small-frame IHI turbochargers since 1978 and can advise on installation procedures for the ST445 application.