Oil filling number 4 cylinder 2007 Rubicon

Around 140,000 miles.
Cyl.#4 gets enough oil in it after shutting off that starting in the morning the cylinder can’t compress.
Causes?

Possible Causes

• Worn Valve Seals
• Bend valve
• Cracked head
• Blown head gasket

Best guess would be a blown head gasket if it runs great otherwise.

• What is a compression test?

CYLINDER HEAD GASKET R&R

REMOVAL

1. Drain cooling system.
2. Disconnect ground cable from battery.
3. Remove upper and lower intake manifolds, Fig. 1.Warning: Intake manifold gasket is made of very thin metal and may cause personal injury, handle with care.
4. Remove cylinder head covers.
5. Then Remove spark plugs from cylinder head.
6. Remove oil level indicator and tube, Fig. 2.
7. Remove exhaust manifold(s).
8. Remove rocker arm and shaft assemblies (2), Fig. 3. Remove push rods and mark positions to ensure installation in original locations.
9. Remove eight head bolts from each cylinder head and remove cylinder heads, Fig. 4.
   INSTALLATION
10. Clean all sealing surfaces of engine block and cylinder heads.
11. Position new gasket(s) on engine block. Lefthand bank gasket is identified with “L” stamped in exposed area of gasket located at front of engine illustrated. Righthand bank gasket is identified with a “R” stamped in exposed area of gasket also, but is located at rear of engine, Fig. 5.
12. Cylinder head bolts should be examined before reuse. If threads are necked down, bolts must be replaced.
13. Necking can be inspected by holding a scale or straight edge against threads. If all threads do not contact scale bolt should be replaced, Fig. 6.
14. Tighten cylinder head bolts 1-8 in sequence illustrated in, Fig. 4. Using 4 step torque turn method, tighten according to following values:
    a. First pass torque bolts (1-8) to 45 ft. lbs. (61 Nm.), Fig. 4.
    b. Second pass torque bolts (1-8) to 65 ft. lbs. (88 Nm.), Fig. 4.
    c. Third pass torque bolts (1-8) to 65 ft. lbs. (85 Nm.), Fig. 4.
    d. Final pass bolts (1-8) to an additional 1/4 turn, Fig. 4. Do not use a torque wrench for this step. Bolt torque after 1/4 turn should be over 90 ft. lbs. (122 Nm.). If not, replace bolt.
15. Inspect and replace worn or bent push rods.
16. Install push rods.
17. Next Install rocker arm and shaft assemblies (2), Fig. 3.
18. Install cylinder head covers.
19. Next Install exhaust manifolds.
20. Install new O-ring on oil level indicator tube and install oil level indicator tube assembly, Fig. 2.
21. Install upper and lower intake manifolds, Fig. 1.
22. Fill cooling system.
23. Connect ground cable to battery.