This is a copy of the instructions from the Ford Service manual - 3.8 v6 engine.
Oil Level Indicator Tube
Removal
1. Remove oil level dipstick (6750) from oil level indicator tube (6754).
2. Remove oil level indicator tube retaining nut from LH exhaust manifold stud.
3. Remove oil level indicator tube from cylinder block (6010).
Installation
1. NOTE: Prior to applying sealer, clean oil level indicator tube and cylinder block sealing surfaces with Metal Surface Cleaner F4AZ-19A536-A or equivalent meeting Ford specification WSE-M5B392-A, to remove all residues that may interfere with the sealer's ability to adhere.
Apply a 3 mm (1/8 inch) bead of Silicone Rubber or D6AZ-19562-BA or equivalent meeting Ford Specifications ESB-M4G92-A and ESE-M4G195-A to oil level indicator tube where oil level indicator tube mates with cylinder block.
2. Install oil level indicator tube into cylinder block.
3. Install oil level indicator tube bracket onto LH intake manifold stud. Install and tighten oil level indicator tube retaining nut to 20-30 N-m (15-22 lb-ft).
4. Install oil level dipstick into oil level indicator tube.