Can I remove and replace lifters in my 02 wrangler sport 6 cylinder with just removing the valve cover?

you dont have to remove the head but you do have to remove valve cover timing chain cover since you will be removing both cams to access the hydraulic lash adjusters {lifters}the link is not the 2.2 but shows what is entailed in removing the cams
Cylinder Head 101 Remove Cams Rockers Lifters

That is a ridiculously high price to replace lifters on a 4 or 6 cylinder engine. On the Mitsubishi 4 cylinder motor, the only thing that is needed to do is remove the valve cover and remove the rocker rod. (2 rods which hold the rocker assembly.) Next is remove the lifters from the bottoms of the rockers and pop in the new ones. Be sure to soak the new lifters in oil for 24-48hrs prior to install so they are pre-filled before install. Replace the rocker assembly and torque down to specs. replace valve cover and then start the vehicle. Check that there is no loud tapping noise and do not race the engine until the lifters have pumped up with engine oil. You should replace oil and filter for this engine work as well.

Wrangler 6 cylinders engines are a straight 6 engine with only one valve cover. The gasket for the valve cover is sold separately from the entire valve cover so it can be replaced.

It is possible, I have seen this done. You have to connect a compressor to a fitting that will screw in and seal in the hole for the spark plug for the cylinder you want to change the lifter on. Pressurize the cylinder so the valves won't drop and do the replacement. Without looking up the repair procedure for a lifter that is as far as I can go with this. In some vehicle the lifter can be replaced without removing the cam but most will require that be done. Make sure you get the repair manual on your vehicle so you have directions for removing and replacing the lifter. I know there are some shops that do this all the time but I have never done it myself.

not a valve, but a lifter. I will paste procedure below. You judge if you can do it or not. Recommend you replace them all while you're in there. If you let this go, the lifter will wear out the camshaft. Lifters are $22 each, and you have 8 of them. You will also need a new valve cover gasket.
Please let me know if you have questions, and thanks for using FixYa.

2.0L Engine
SOHC engine
See Figures 6, 7, 8 and 9

1. Disconnect the engine air cleaner-to-valve cover hose from the cover by compressing the hose clamp with pliers and sliding the clamp back, then separate the hose from the cover.
2. Remove the spark plug wire separators from the valve cover and set the wire assemblies aside.
3. Unfasten the three valve cover retaining bolts.
4. Remove the valve cover and gasket from the cylinder head.
   

WARNING Do not use any abrasive grinding discs to remove gasket material. Use a plastic manual gasket scraper to remove the gasket residue. Be careful not to scratch or gouge the aluminum sealing surfaces when cleaning them.

1. Remove the old gasket material from the cylinder head and valve cover mating surfaces.

Fig. Fig. 6: Remove the spark plug wire separators from the valve cover

Fig. Fig. 7: Compress the engine air cleaner-to-valve cover hose clamp with pliers, and slide the clamp back ...

Fig. Fig. 8: ... then disconnect the hose from the valve cover

Fig. Fig. 9: Unfasten the valve cover retainers and remove the valve cover-2.0L SOHC engine

If removing more than one valve lifter (tappet), mark the lifters and their locations as they must be installed in their original bores.

1. Remove the rocker arm(s).
2. Unfasten the lifter guide plate retainer.
3. Remove the guide plate and the lifter.

To install:

1. The oil feed hole in the lifter must face away from the oil feed hole in the cylinder head.
2. Lubricate the lifter(s) with clean 5W-30 engine oil and install them in their original bores.

Make sure the lifter guide plate retainer tabs are towards the rear of the cylinder head, and the lifter guide plate tabs are towards the front of the cylinder head.

1. Install the lifter guide plate and tighten the retainer.
2. Install the rocker arms.
   

Do not use any sealer with a silicone type gasket.

1. Install a new gasket and the valve cover.
2. Install and tighten the valve cover retainers to 71-97 inch lbs. (8-11.5 Nm).
3. Attach the spark plug wire separators to the cylinder head.
4. Connect the engine air cleaner-to-valve cover hose and engage the hose clamp

Depends on which engine you have. If you have

ADJUSTMENT Although it is sometimes possible to reuse an old cylinder head cover gasket, in most cases it makes more sense to purchase a new one before beginning the procedure. Some vehicles may require the use of silicone sealant either with or without a new cover gasket. For more details, please refer to the cylinder head cover procedures in Engine & Engine Overhaul of this repair guide and refer to the gasket manufacturer's instructions.

Z24i Engine
See Figures 1, 2 and 3
For the intake valves: 1-4-5-8 valve clearance is 0.012 in. (0.30mm). For the exhaust valves: 2-3-6-7 valve clearance is 0.012 in. (0.30mm). The pivot locknut torque specification is 12-16 ft. lbs. (16-22 Nm).

1. The valves must be adjusted with the engine warm, so start the truck and run the engine until the needle on the temperature gauge reaches the middle setting. After the engine is warm, shut it off.
2. Note the location of any wires and hoses which may interfere with cylinder head cover removal, disconnect them and move them to one side. Remove the bolts holding the cylinder head cover in place and remove the cover. Remember, the engine will be hot, so be careful!

Fig. Fig. 1: Check the valve clearance with a flat feeler gauge-Z24i engine

Fig. Fig. 2: Loosen the locknut and turn the adjusting screw to adjust the valve clearance-Z24i engine

Fig. Fig. 3: With the No. 1 piston at TDC, adjust the top set of valves FIRST; with the No. 4 piston at TDC, adjust the bottom set of valves SECOND-Z24i engine

1. Rotate the crankshaft until the timing marks indicate that the No. 1 piston is at TDC of the compression stroke. If you're not sure of which stroke you're on, remove the No. 1 spark plug and hold your thumb over the hole. Pressure will be felt as the piston starts up on the compression stroke.
2. Refer to the accompanying illustration (upper part), then check valves (1), (2), (4) and (6) using a flat bladed feeler gauge. The feeler gauge should pass between the valve stem end and the rocker arm screw with a very slight drag. Insert the feeler gauge straight, not at an angle.
3. If the clearance is not within the specified value, loosen the rocker arm lock nut and turn the rocker arm screw to obtain the proper clearance. After correct clearance is obtained, tighten the locknut.
4. Rotate the crankshaft until the timing marks indicate that the No. 4 piston is at TDC of the compression stroke. If you're not sure of which stroke you're on, remove the No. 4 spark plug and hold your thumb over the hole. Pressure will be felt as the piston starts up on the compression stroke.
5. See the illustration (lower part), then check valves (3), (5), (7) and (8). Check and adjust valve clearance as necessary.
6. Install the cylinder head cover gasket, the cover itself and any wires or hoses which were removed. Check the engine oil level.

KA24E, VG30i and VG30E Engines
See Figures 4 and 5
These models utilize hydraulic valve lifters. Periodic adjustment is neither necessary or possible. There is however a bleed down procedure that is necessary when the valve train has been disassembled.
HYDRAULIC LIFTER BLEED DOWN

1. Remove the cylinder head cover.
2. Check the lifters for proper operation by pushing hard on each lifter with fingertip pressure.
3. If the valve lifter moves more than 0.04 in. (1mm), air may be inside it. Make sure the rocker arm is not on the cam lobe when making this check.
4. Install the cylinder head cover.
5. If there was air in the lifters, bleed the air by running the engine at 1000 rpm for 10 minutes.

Fig. Fig. 4: Cross-sectional view of an installed hydraulic valve lifter-4 cylinder engine

Fig. Fig. 5: Cross-sectional view of an installed hydraulic valve lifter-6 cylinder engine

We have an 02 Liberty 3.7L, here at my repair shop, after customer replaced, spark plug's and all coil pack's, brought it here to my shop, was running with two cylinder's miss, did cylinder compression test, no compression on two cylinder's, remove valve cover's, found two rocker arm's off, remove cylinder head's, and found that on those two cylinder's the valve seat's had drop, keeping the valve open, and that's why the two rocker arm's had come off, do a cylinder compression test, could be the same thing, hope this was very helpful.

Hydraulic Lifters REMOVAL & INSTALLATION 4.8L Engines

1. Remove the rocker cover.
2. Remove the engine side cover.
3. Back off the rocker arm adjusting nuts and remove the pushrods. Keep them in order for installation.
4. Reaching through the side cover opening, lift out the hydraulic lifters. If your are going to re-use the lifters, remove them one at a time and mark each one for installation. They must be re-installed in the same locations. If a lifter is stuck, it can be removed with a grasping-type lifter tool, available form most auto parts stores.
   
5. Inspect each lifter thoroughly. If any of them shows any signs of wear, heat bluing or damage, replace the whole set. To install:
   
6. Install and coat each lifter with engine oil supplement.
7. Install the remaining components by reversing the removal procedure.
8. Once installation is complete, adjust the valves as described in the valve lash procedure. Fig. 1: Stuck lifters must be freed using a slide hammer type lifter removal tool
   

4.3L, 5.0L, 5.7L And 7.4L Engines

1. Remove the cylinder head cover.
2. Remove the intake manifold.
3. Back off the rocker arm adjusting nuts and remove the pushrods. Keep them in order for installation.
4. Remove the lifter retainer bolts, retainer and restrictor.
5. Remove the lifters. If your are going to re-use the lifters, remove them one at a time and mark each one for installation. They must be re-installed in the same locations. If a lifter is stuck, it can be removed with a grasping-type lifter tool, available from most auto parts stores.
6. Inspect each lifter thoroughly. If any of them shows any signs of wear, heat bluing or damage, replace the whole set.
7. Coat each lifter with engine oil supplement prior to installation. Tighten the retainer bolts to 12 ft. lbs. (16 Nm). Adjust the valves as described in the valve lash procedure.

6.2L And 6.5L Diesel Engines Fig. 2: Diesel engine valve lifter

1. Remove the cylinder head cover.
2. Remove the rocker arm shaft, rocker arms and pushrods. Keep all parts in order and properly identified for installation.
3. Remove the clamps and lifter guide plates.
4. Remove the lifters by reaching through the access holes in the cylinder head with a magnetic lifter tool. If you are going to re-use the lifters, remove them one at a time and mark each one for installation. They must be re-installed in the same locations. If a lifter is stuck, it can be removed with a grasping-type lifter tool, available form most auto parts stores. To install:
   
5. Inspect each lifter thoroughly. If any of them shows any signs of wear, heat bluing or damage, replace the whole set. NOTE: Some engines will have both standard and 0.010 in. (.0039mm) oversize lifters. The oversized lifters will have "10'' etched into the side. The block will be stamped "OS'' on the cast pad next to the lifter bore. and on the top rail of the crankcase above the lifter bore. WARNING
   New lifters must be primed before installation. Damage to the lifters and engine will result if new lifters are installed dry!
   
6. Prime new lifters by immersing them in clean kerosene, engine oil or diesel fuel and working the lifter plunger while the unit is submerged.
7. Prior to installation, coat the lifter roller with engine oil supplement. Re-used lifters must be installed in their original positions!
8. Install the lifters.
9. Install the guide plates and clamps. Tighten the clamp bolts to 18 ft. lbs. (26 Nm).
10. After all the clamps are installed, turn the crankshaft by hand, 2 full turns (720°) to ensure free movement of the lifters in the guide plates. If the crankshaft won't turn, one or more lifters may be jamming in the guide plates.
11. The remainder of assembly the reverse of disassembly.

Please don't forget to rate!!!!

2.2L Engine When installing new lifters, a pre-lube should always be applied to the lifter body. It is also a good idea to prime hydraulic lifters by submerging them in clean engine oil and depressing the plunger using an old pushrod. This allows the internal components of the hydraulic lifter to coat with oil before initial operation in the engine. All lifters should be replaced when a new camshaft is installed.
If any valve train components (lifters, pushrods, rocker arms) are to be reused, they must be tagged or arranged during removal to assure installation in their original locations.

1. Remove the rocker arm cover.
   
2. Remove the cylinder head assembly from the engine.
   
3. Remove the bolts retaining the lifter anti-rotation brackets, then remove the brackets.
   
4. Remove the hydraulic roller lifters from the bores.
   
5. Inspect the lifter and lifter bore for wear and scuffing. Examine the roller for freedom of movement and/or flat spots on the roller surface.
   

Remove the bolts retaining the lifter anti-rotation brackets ...



... then remove the anti-rotation brackets



The lifters are located in bores in the engine block



Use a lifter removal tool to remove the lifters from the bore

To install:
If installing a new lifter, coat the lifter body with a suitable camshaft pre-lube

1. Install each hydraulic lifter to its bore being careful to align the flat sides (top) of the lifters with the flat sides of the anti-rotation brackets. When properly installed the flat sides of each lifter are aligned parallel to the anti-rotation bracket. The roller at the bottom of the lifter is parallel to the camshaft lobe.
   

Make sure to properly align and install each lifter as improper installation of the lifters or brackets could result in engine damage.

1. Install the anti-rotation bracket retaining bolts and tighten to 97 inch lbs. (11 Nm).
   
2. Install the cylinder head.
   
3. Install the rocker arm cover.
   

Removing the hydraulic roller lifter from the 2.2L engine

possibly a collapsed valve lifter.. intake manifold must be removed to replace it... to confirm.. remove the valve cover and see if the rockers can be compressed by hand..if so probably the lifter