Description
Jeep 4.0L L6 Remanufactured Engine – Professional Overview
The Jeep 4.0L L6 Remanufactured Engine is a replacement powerplant specified for select Jeep applications from 1999 through 2006.
This engine uses a 4.0L inline-six (L6) configuration and is identified by block casting numbers 27AB and 28AB. The supplied product information also identifies VIN code S as an application reference.
For engine replacement, matching displacement alone is not sufficient. The vehicle’s model year, application, original engine configuration, casting information, and VIN details should be checked against the available fitment information before ordering.
This engine is professionally remanufactured through a structured process that includes complete disassembly, cleaning, inspection, machining, installation of specified new components, final assembly, and testing.
Fitment and Application Information
The engine is listed for 1999–2006 Jeep 4.0L L6 applications.
The supplied identification details include:
- Engine: 4.0L L6
- Block casting numbers: 27AB, 28AB
- VIN code: S
- Application years: 1999–2006
- Vehicle brand: Jeep
Exact fitment should be confirmed using the vehicle fitment information and applicable casting numbers before purchase.
This is particularly important when replacing an engine across multiple model years, as engine configurations and vehicle applications can vary even when the displacement remains the same.
How the Engine Is Remanufactured
The remanufacturing process begins with complete disassembly and deep cleaning. Cast-iron components are hot tanked, while aluminum components are thermally cleaned to prepare them for detailed inspection.
The components are then inspected for defects and potential damage. Magnaflux testing uses magnetic particles to identify microscopic cracks and fissures, while visual inspection provides an additional evaluation of component condition.
During the machining and rebuilding stage, deck surfaces are CNC machined and specified new components are installed. The supplied process includes new bearings, pistons, rings, lifters, oil pump, gaskets, Viton valve seals, freeze plugs, and galley plugs.
Timing components are also addressed during the rebuild. Depending on the engine design, the process includes a new timing chain with new tensioners or a new timing belt with a new tensioner. If the engine uses a timing-driven water pump, a new pump is installed.
After final assembly, the engine undergoes SIM testing. The cooling and oil systems are fully pressurized, while the crankshaft is spun at high RPM to verify compression and build quality.
What Buyers Should Know Before Installation
When purchasing a replacement Jeep engine, it is important to verify the exact configuration rather than relying only on the 4.0L displacement.
The 27AB and 28AB block casting numbers, VIN code S, production year, and vehicle application provide useful identification information for confirming compatibility.
Buyers should compare these details with the original engine and the vehicle fitment information before ordering.
Proper diagnosis of the original engine failure is also important before installation so that the underlying cause of the failure can be addressed where necessary.
Why This Engine Is a Practical Replacement
The Jeep 4.0L L6 is supplied through a structured remanufacturing process rather than as an engine with an unknown used history.
The process incorporates multiple quality-control stages, including deep cleaning, Magnaflux inspection, machining, installation of specified new components, final assembly, and SIM testing.
For Jeep owners and professional repair facilities seeking a compatible 4.0L inline-six replacement engine, these procedures provide clearly defined checkpoints throughout the rebuilding process.
Who This Engine Is Best For
This 4.0L L6 remanufactured engine is intended for buyers who require a replacement engine for a compatible 1999–2006 Jeep application.
It can be suitable for:
- Jeep owners replacing a failed 4.0L engine
- Automotive repair shops sourcing replacement powertrains
- Professional technicians performing engine replacement work
- Restoration and refurbishment projects involving compatible Jeep vehicles
- Buyers specifically searching for a Jeep 4.0L replacement engine
Before purchasing, confirm the vehicle year, application, engine configuration, VIN information, and applicable block casting numbers.
Technical Specifications
| Specification | Details |
|---|---|
| Product Type | Remanufactured Engine |
| Engine Type | 4.0L L6 |
| Configuration | Inline 6-cylinder |
| Application Years | 1999–2006 |
| Vehicle Brand | Jeep |
| Block Casting Numbers | 27AB, 28AB |
| VIN Code | S |
| Engine Condition | Remanufactured |
| Cleaning Process | Hot tanking for cast iron / thermal cleaning for aluminum |
| Inspection | Magnaflux testing and visual inspection |
| Machining | CNC-machined deck surfaces |
| Testing | SIM tested after assembly |
| Warranty | Up to 7 years / 1 million miles, with optional Pure Care no-fault protection |
Ordering and Support
Before ordering the Jeep 4.0L L6 Remanufactured Engine, compare the vehicle’s exact application with the supplied engine specifications.
The product information recommends verifying fitment using the vehicle fitment information and applicable casting numbers. The 27AB and 28AB casting numbers and VIN code S can provide additional identification points when comparing the replacement with the original engine.
The remanufacturing process includes inspection, machining, component replacement, assembly, and SIM testing to establish quality-control checkpoints throughout the rebuild.
Buyers can also explore related products within the remanufactured engine category when comparing replacement options for different Jeep applications.
Frequently Asked Questions
What type of engine is this?
This is a 4.0L inline-six (L6) remanufactured engine specified for select Jeep applications from 1999 through 2006. The supplied identification information lists block casting numbers 27AB and 28AB and VIN code S.
What years does this Jeep 4.0L engine cover?
The product is listed for 1999–2006 Jeep applications. Exact compatibility should be verified using the vehicle fitment information and applicable casting numbers before ordering.
What are the block casting numbers?
The listed block casting numbers are 27AB and 28AB. These numbers can be compared with the original engine as part of the fitment verification process.
How is this engine remanufactured?
The engine is completely disassembled and deeply cleaned before inspection and machining. New specified components are installed during rebuilding, followed by final assembly and SIM testing.
How is the finished engine tested?
The engine undergoes SIM testing after assembly. Its cooling and oil systems are fully pressurized, and the crankshaft is spun at high RPM to verify compression and build quality.
What components are replaced during the rebuild?
The specified process includes new bearings, pistons, rings, lifters, oil pump, gaskets, Viton valve seals, freeze plugs, and galley plugs. Timing components and a timing-driven water pump are replaced when applicable.
What warranty is available?
The supplied product information states that each engine comes with up to 7 years and 1 million miles of warranty, with an option to upgrade to Pure Care no-fault protection.
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