Repair guides, torque specs and fluid capacities for the 4.0L inline six, with every fact checked against two independent sources, one of them always the workshop manual.
Jeep 4.0L torque specs: head bolt sequence, mains, manifold
Tighten 4.0L head bolts in the factory sequence: all 14 to 22 ft-lb, then all to 45 ft-lb, then bolts 1–10 and 12–14 to 110 ft-lb and bolt 11 to only 100 ft-lb [1][2]. Coat bolt 11's threads with sealant and install the gasket dry [1][2]. Main caps go to 40, 70, then 80 ft-lb, with cap 3 done last [1][2].
Tightening order, redrawn from the factory manual (Fig. 56) and the 1993 service data (Fig. 3). Head viewed from above with the front of the engine to the left. Bolt 11 (red, dashed ring) gets 100 ft-lb, not 110.
Install the head gasket dry, with no sealing compound.[1][2]
Coat the threads of bolt 11 with sealant (the factory manual specifies Loctite 592 or equivalent).[1][2]
All 14 bolts, in sequence, to 22 ft-lb (30 N·m).[1][2]
All 14 bolts, in sequence, to 45 ft-lb (61 N·m).[1][2] The factory manual also has you re-check all 14 at 45 ft-lb before the final step.[1]
Bolts 1–10 and 12–14 to 110 ft-lb (149 N·m); bolt 11 to 100 ft-lb (135 N·m).[1][2] The factory manual warns not to over-tighten bolt 11.[1]
Paint-mark each bolt. Head bolts can be reused only once.[1][2]
Verified torque values
Each value below is from the factory service manual (the 2000 manual, cross-checked against the 1994, 1995, 1997, 1999 and 2001 editions where they cover it) and at least one independent source. Where the torque changed between years, the row says which years it covers.
The 2000 and 2001 Group 9 4.0L torque tables say 126 in-lb (14 N·m), the same figure printed in the 2.5L table beside it; every 4.0L procedure says 23 ft-lb (31 N·m). The 1993 data says 17 ft-lb (23 N·m), which looks like the newton-meter and foot-pound figures swapped. Not verified for 1984–93.
1994–2001: Group 11 procedure and torque table (1994), installation procedure (1995, 1999, 2000, 2001); 2001 data
The independent source lists the same 4.0L engine in the TJ Wrangler, not the XJ. No XJ-specific independent source has been found; the 1993 and 2001 service data tables do not list the drain plug.
1995, 1997 and 2000 factory manual 4.0L tables; ExtremeTerrain 4.0L list (TJ Wrangler page)
Not verified for 1995: that manual's 4.0L section says 115 in-lb (13 N·m), the figure other years give for the 2.5L. The 1993 data says 80 in-lb (9 N·m).
1994, 1997, 1999, 2000 and 2001 factory manuals; 2001 data
The factory ignition chapter (Group 8D) gives a range of 26–30 ft-lb (35–41 N·m), and its 1999–2001 specification table says 30 ft-lb (41 N·m), which is where the 30 ft-lb figure comes from. 27 ft-lb is inside the factory range.
1994, 1995, 2000 and 2001 factory manuals, Group 9; 1993 data
Head bolts, re-check all 14 at 45 ft-lb before the final step
45 ft-lb (61 N·m)
Why not verified: Only the factory manuals list this check step (both are the same source family). The 1993 and 2001 service data give three stages with no re-check. It does no harm to do it.
Why not verified: Not a mix-up between fasteners: the 1993 and 2001 service data both list flexplate-to-crankshaft at 55 ft-lb separately from flywheel-to-crankshaft at 105 ft-lb. The factory manuals (1994–2001) give only "Flywheel to Crankshaft 105 ft-lb" for the 4.0L and no separate flexplate figure; their 30RH/32RH chapters (2.5L XJ and 4.0L YJ) give 55 ft-lb for "driveplate to crankshaft". A 1998 CHARM text, read only from Google's index, gives 105 ft-lb for "flywheel or converter plate". No factory figure for the XJ 4.0L with AW4 has been found.
Automatic transmission (AW4); this is the flexplate-to-crankshaft fastener in every source
Why not verified: A different, smaller fastener from the flexplate-to-crankshaft bolts. The factory manuals give 40 ft-lb (54 N·m) only in the 2.5L engine chapter; the 4.0L and AW4 chapters give no figure.
Why not verified: Factory manuals only. The 1993 data agrees on the 5/16 in. bolts (156 in-lb) but gives 114 in-lb (13 N·m) for the 1/4 in. bolts. The torque dropped to 84/132 in-lb in the 1997 and later manuals.
1994 and 1995 factory manuals (procedure and table)
Manifold fasteners 6 and 7. Every 4.0L installation procedure (1994–2001) says 23 ft-lb (31 N·m), and so does the 1994 Group 11 table.[1][4][5][7][8] The 2000 and 2001 Group 9 tables say 126 in-lb (14 N·m), the 2.5L figure printed beside them.[1][8] We use 23 ft-lb, which the 2001 service data also gives.[3]
Spark plugs. The engine chapter says 27 ft-lb (37 N·m); the ignition chapter allows 26–30 ft-lb (35–41 N·m), and its 1999–2001 table says 30 ft-lb (41 N·m).[1][4][5][7][8] The 1993 service data also says 27 ft-lb.[10]
Valve cover. The 1995 manual’s 4.0L section says 115 in-lb; the 1994 and 1997–2001 manuals say 85 in-lb, as does the 2001 service data.[1][3][4][5][7][8][9]
FAQ
Why is head bolt 11 torqued lower on a 4.0L?
Both the 2000 factory manual and the 1993 service data give 100 ft-lb for bolt 11 and 110 ft-lb for the rest, and both call for sealant on its threads [1][2].
Can I reuse 4.0L head bolts?
Only once. Paint-mark them after tightening, and discard any bolt that already has paint on it or whose history you don't know [1][2].
What is the 4.0L main bearing cap torque?
Tighten caps 1, 2 and 4–7 to 40, then 70, then 80 ft-lb. Then load the crank fore-aft and do cap 3 in the same three steps [1][2].
What is the spark plug torque on a Jeep 4.0?
27 ft-lb (37 N·m), per the factory manual's engine chapter and the 1993 service data [1][10]. The factory ignition chapter allows 26–30 ft-lb (35–41 N·m), which is why some sources say 30 ft-lb [4][7].
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Verified. Two independent sources agree, and one of them is factory data.
Single source. Only one source gives this figure.
Not yet verified. It has not been checked against that rule yet.
Sources conflict. The sources do not agree, so both figures are shown.
2 catalogs. Two independent catalogs agree on an aftermarket number. Factory catalogs do not list those.
Every published fact needs two independent sources, one of them factory data. Anything short of that is flagged.