Dodge Dakota (R1). Manual

ENGINE 2.5L

DESCRIPTION

The 2.5 liter (150 CID) four-cylinder engine is an

In-line, lightweight, overhead valve engine.

This engine is designed for unleaded fuel. The

engine cylinder head has dual quench-type combus-
tion chambers that create turbulence and fast burn-
ing of the air/fuel mixture. This results in good fuel
economy.

The cylinders are numbered 1 through 4 from front

to rear. The firing order is 1-3-4-2 (Fig. 1).

The crankshaft rotation is clockwise, when viewed

from the front of the engine. The crankshaft rotates
within five main bearings and the camshaft rotates
within four bearings.

The engine Build Date Code is located on a

machined surface on the right side of the cylinder
block between the No.3 and No.4 cylinders (Fig. 2).

The digits of the code identify:
• 1st Digit—The year (8 = 1998).

• 2nd & 3rd Digits—The month (01 - 12).

• 4th & 5th Digits—The engine type/fuel system/

compression ratio (HX = A 2.5 liter (150 CID) 9.1:1
compression ratio engine with a multi-point fuel
injection system).

• 6th & 7th Digits—The day of engine build (01 -

31).

FOR EXAMPLE: Code * 801HX23 * identifies a

2.5 liter (150 CID) engine with a multi-point fuel
injection system, 9.1:1 compression ratio and built on
January 23, 1998.

DIAGNOSIS AND TESTING—ENGINE
DIAGNOSIS - INTRODUCTION

Engine diagnosis is helpful in determining the

causes of malfunctions not detected and remedied by
routine maintenance.

These malfunctions may be classified as either

mechanical (e.g., a strange noise), or performance
(e.g., engine idles rough and stalls).

(Refer to 9 - ENGINE - DIAGNOSIS AND TEST-

ING - Preformance) or (Refer to 9 - ENGINE - DIAG-
NOSIS AND TESTING - Mechanical). Refer to 14 -
FUEL SYSTEM for fuel system diagnosis.

Additional tests and diagnostic procedures may be

necessary for specific engine malfunctions that can-
not be isolated with the Service Diagnosis charts.
Information concerning additional tests and diagno-
sis is provided within the following:

• Cylinder Compression Pressure Test (Refer to 9 -

ENGINE - DIAGNOSIS AND TESTING)

• Cylinder Combustion Pressure Leakage Test

(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

• Cylinder Head Gasket Failure Diagnosis (Refer

to 9 - ENGINE/CYLINDER HEAD - DIAGNOSIS
AND TESTING)

• Intake Manifold Leakage Diagnosis (Refer to 9 -

ENGINE/MANIFOLDS/INTAKE

MANIFOLD

DIAGNOSIS AND TESTING)

• Lash Adjuster (Tappet) Noise Diagnosis (Refer to

9 - ENGINE/ENGINE BLOCK/HYDRAULIC LIFT-
ERS (CAM IN BLOCK) - DIAGNOSIS AND TEST-
ING)

• Engine Oil Leak Inspection (Refer to 9 - ENGINE/

LUBRICATION - DIAGNOSIS AND TESTING)

Fig. 1 Engine Firing Order

Fig. 2 Build Date Code Location

1 - NO. 4 CYLINDER
2 - NO. 3 CYLINDER
3 - DAY
4 - MONTH
5 - YEAR
6 - MACHINED SURFACE

ENGINE 2.5L

9 - 3

Dodge Dakota (R1). Manual - part 453