The AMC 2.5L Inline-4 engine was developed by American Motors Corporation (AMC) that was used in AMC, Jeep, and Dodge vehicles. The engine block and head are both made of cast iron, and features an Overhead Valve (OHV) design with 2 valves per cylinder. Production began in 1984 and seized in 2002.
The AMC Inline-4 engine began production after 3 years of development within AMC. It was specifically designed to be used in Jeeps, and was not designed as a standard passenger car engine.
The 2.5L was produced between 1984-2002. Just like the other inline engines AMC created, it was considered reliable and inexpensive to repair. The 1984 and 1985 model years were paired with a single barrel carburetor. In 1986 the engine was paired with the Renix computer system and changed over to Throttle-body Fuel Injection (TBI) which injected fuel into the throttle body.. In 1991, the engine fuel delivery system was again updated to the Mopar Sequential Multi-Point Fuel Injection system (MPFI), which injects fuel above each cylinder’s intake valve.
This engine was used in a variety of vehicles throughout AMCs lineup – but here are some of the Jeeps you can find it in:
- 1983-1984 Jeep DJ-5M
- 1984-1986 Jeep CJ-7
- 1984-2000 Jeep Cherokee
- 1986-1992 Jeep Comanche
- 1987-2002 Jeep Wrangler
Engine Power Specifications
| YEAR | HP | TQ |
|---|---|---|
| 1984-1985 | 105hp @ 5000rpm | 132lb-ft @ 2800rpm |
| 1986-1990 (TBI) | 117hp @ 5000rpm | 135lb-ft @ 3500rpm |
| 1991-2002 (MPFI) | 120hp @ 5250rpm | 139lb-ft @ 3250rpm |
Oil Types and Capacities
| Viscosity | Above 0°F: 10W-30 Below 60°F: 5W-30 |
| Capacity | 4 qts (3.8L) |
| Oil Filter | Mopar 5281090AB WIX 51085 |
| Drain Plug Torque | 30ft-lbs |
Tune-up Parts
| Spark Plug | 1984-1985: Champion 82 1986-1998: Champion 412 1999-2002: Champion 438 |
| Plug Wires | 1984-1990: NGK 53292 1991-2002: NGK 53186 |
Common Problems
Lifter Tick
Lifter tick is a common issue on these engines. While essentially harmless, many people do not enjoy the sound of the top of the engine slightly ticking when running. Besides replacing rockers and lifters, the only solution I’ve seen to work is to use a zinc additive in your oil or switch to an oil type that includes higher levels of zinc. One of the most recommended oils to use in the 2.5L engine (and 4.2L & 4.0L for that matter) is the Shell Rotella Diesel Engine Oil. The oil works great in the engine and includes lots of Zinc. As a result, this engine oil usually reduces lifter tick noise.
Modification
Since the 2.5L engine is a low-powered engine, it’s not common that people modify them. A common upgrade to the engine would be to swap it out for a 4.0L engine.
