Find the fix for your 4.0L inline six
Search a symptom, a spec or a part number, or pick a full procedure below.
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Quick specs
Firing order, 4.0L six
1-5-3-6-2-4
Factory manuals 1994–2001 (Group 9 text and Group 8D figures); 1993 data; ExtremeTerrain lists it for every XJ 4.0L
Open the source for Firing order, 4.0L sixEngine oil, 4.0L, with filter change
6.0 qt (5.7 L)
1997–2001 (factory manual). Same figure in the 1984–88 and 1989–95 data and the 2001 data.
Open the source for Engine oil, 4.0L, with filter changeHead bolts 1–10 and 12–14, final, in sequence
110 ft-lb (149 N·m)
2000 factory manual; 1993 data; 2001 data
Open the source for Head bolts 1–10 and 12–14, final, in sequenceSpark plug gap, 4.0L
0.035 in (0.89 mm)
Factory manuals 1994, 1995, 1997, 1999, 2000, 2001; 1993 data; 2001 data; ExtremeTerrain (all XJ years)
Open the source for Spark plug gap, 4.0L
Guides
Guides are the sourced pages: symptoms, specs, and explainers. Open one to read the checks, the values, and where they came from.
- Spec
Jeep 4.0L oil pressure: normal readings, low pressure and the sending unit
Factory oil pressure specs for the 4.0L Cherokee XJ at idle and at speed, the causes of low pressure in order, and how to tell a bad sender from a real problem.
2 min read - Symptom
Jeep Cherokee XJ idle air control motor: symptoms, codes and checks
How the idle air control motor sets idle on a 4.0L Cherokee XJ, the codes it sets, what you can and can't adjust, and how to check it before buying one.
3 min read - Symptom
Jeep Cherokee XJ throttle position sensor: symptoms and how to test it
What the TPS does on a 4.0L Cherokee XJ, the factory voltmeter test by year, the trouble codes, and how to fit a new sensor without binding.
6 steps3 min read - Explainer
Renix vs HO vs OBD-II: which 4.0L Cherokee XJ do you have?
The 4.0L XJ changed engine computers twice. How to tell a Renix, HO or OBD-II truck apart, and why it changes the parts, codes and tests that apply.
2 min read - Spec
Jeep 4.0L firing order and spark plug gap (plus the 2.5L)
Jeep 4.0L firing order 1-5-3-6-2-4 with cylinder numbering, the 2.5L order, spark plug gap, factory plug numbers and torque, checked against the factory manual.
5 steps1 min read - Spec
Jeep 4.0L torque specs: head bolt sequence, mains, manifold
4.0L Jeep head bolt sequence and torque steps (including bolt 11), main caps, manifold and other values, checked against the factory manual.
6 steps1 min read - Symptom
Jeep Cherokee XJ crankshaft position sensor: symptoms, tests, part numbers
How a failing CPS shows up on a 4.0L Cherokee XJ, where it is, the factory voltage checks for 1993–2001, bolt torque and part numbers by year.
4 min read - Spec
Jeep Cherokee XJ fluid capacities: oil, coolant, transmission, axles
Oil, coolant, transmission, transfer case and axle fluid capacities for the 4.0L Cherokee XJ, checked against the factory manual, with conflicts shown.
1 min read - Symptom
Jeep XJ 4.0L cranks but won't start: step-by-step diagnosis
A step-by-step crank-no-start check for the 4.0L Cherokee XJ: codes, relays, fuel pump prime, spark, fuel pressure by year and the crank sensor.
7 steps2 min read - Symptom
Jeep XJ 4.0L overheating: a step-by-step checklist
Why a 4.0L Cherokee XJ overheats and what to check, in order: coolant, cap, trapped air, fan clutch, electric fan, thermostat, radiator, water pump and head.
8 steps3 min read
- Symptom
Systems
Systems are the parts of the vehicle. Open one to see every published guide for that system.
Engine (4.0L & 2.5L)
The AMC 242 4.0L inline-six: Renix, HO and OBD-II versions, head, seals, oil and belts.
Fuel & ignition
Crankshaft position sensor, TPS, IAC, fuel pump, heat soak and ignition.
Cooling
Overheating, thermostat, radiator, fan clutch, water pump and heater core.
Diagnose a problem
Step-by-step flowcharts: crank-no-start, stalling, rough idle.
Specs
Fluid capacities and torque tables, sourced and year-split.
Coming next
These systems have no published guides yet. They are listed here so you know what is still being checked.
- Transmission
- Transfer case
- Axles
- Electrical
- Body & rust
- Steering & suspension
- Buyer's guide
Full procedures
A full procedure lays out the steps and the values that go with them. Open one when you already know the repair.
Jeep 4.0L rear main seal leak: how to confirm it, and how to fix it
How to tell a 4.0L XJ rear main seal leak from oil filter, distributor or plug leaks using the factory dye check, then replace the two-piece seal.
Jeep Cherokee XJ 4.0L water pump: symptoms, replacement and torque
How to tell a 4.0L XJ water pump is failing, why it has to be a reverse-rotation pump, the factory removal order, and the bolt torque by year.
How we check facts
Two independent sources
A value is verified only when two sources that do not copy each other say the same thing.
One is always factory data
At least one of those sources is a factory manual or another factory document.
Unconfirmed facts are flagged
Anything short of that is marked Single source, Not yet verified, Sources conflict, or 2 catalogs.
- 12Published guides
- 202Spec values and part numbers
- 121Verified
- 81Flagged