REMOVAL & INSTALLATION
See Figures 1 through 9
The oil pan must be pulled downward as much as 6 in. (15.2 cm) to clear the oil pickup. In many cases, this requires that the engine mounts be disconnected and the engine raised to clear a crossmember underneath the shallower section of the pan.
If raising the engine is needed, support the vehicle securely high enough to allow easy access to the underside. Refer to the engine removal and installation procedures and disconnect all the hoses and wires that would prevent the engine from being lifted the necessary distance.
Support the engine on the hoist and remove the through-bolts from the mounts. Elevate the engine only enough to gain the needed clearance and keep a close watch for interference with other components as the engine is raised.
Removal of the lower engine cover may be necessary to access the oil pan on some engines.
- Disconnect the negative battery cable. Drain the engine oil. When the pan is empty, reinstall the drain plug finger-tight.
- Remove the bolts holding the oil pan. The length may vary by location. Keep the bolts in order or identify them so that they may be correctly installed.
- Most engines use a bead of sealer on the oil pan rather than a paper gasket. After the bolts are removed, tap the corners of the pan with a rubber or plastic mallet. If the pan pops loose, it may be removed on the spot. In most cases, the pan will remain firmly glued to the block. Insert the special gasket slicing tool (MB 998727 or equivalent) by tapping it into place with a mallet or hammer. Once in place, drive the tool along the pan to release the sealer and the pan.
DO NOT attempt to loosen the pan with a screwdriver or chisel. The flange of the pan will deform and cause oil leaks after reassembly.
- When the pan is removed, both the flange surface of the pan and the matching surface of the block must be completely cleaned of any remaining gasket or sealer. When cleaning with a scraper, take great care not to gouge or mar the metal surfaces.
- With the pan removed, the oil pick-up screen and tube may be removed by unbolting it from the block. If removed, it should be thoroughly cleaned in a solvent bath and air dried before reinstallation. The gasket surfaces must be cleaned and the old gasket discarded.
- Clean the oil pan with solvent, taking great care to remove all particulate matter and sludge before air drying. The pan must be reinstalled free of any matter which could be circulated through the engine. Remove the drain plug, replace the washer and reinstall the plug, tightening it.
- If the pick-up was removed, reinstall it with a new gasket and tighten the bolts to 13 ft. lbs. (18 Nm).
- On all engines except for the diesel engines, apply a thin bead of sealant (MZ 100168 or equivalent) all around the pan. Cut the tip of the sealant tube to allow a bead about 0.16 in (4mm) to flow. The sealant goes in the groove in the pan flange. Note that the bead should flow to the inside of the bolt holes or between the bolt and the pan. The V6 engines also receive the bead of sealer but the area between the two rear-most bolt holes must not be sealed. Care must be taken to prevent oozing of sealant into the rear valley of the pan. The diesel truck engines use a paper gasket which does not require sealant. Sealant such as 3M;rm ART 8660 or its equivalent must be applied to the block at the four seams where the front and rear cases join. Apply the sealer only to these areas.
- Once the sealant is applied, the pan must be installed within 10 minutes or the sealant becomes unusable. Fit the pan into place and install the bolts finger-tight only, making certain the bolts are replaced in the correct holes as determined by their length.
- Tighten the pan bolts evenly and alternating from side to side to 5 ft. lbs. (7 Nm) only. The pan bolts for the 6-cylinder engine must be tightened in the pattern shown; the pattern may be used as a guide for the correct tightening of other pans.
- Since the oil has been drained, replacement of the oil filter is recommended before refilling the engine oil.
- Install the correct amount of engine oil. Make sure the drain plug is tight before pouring the oil.
- If the engine is supported by a hoist, lower it into position and secure the mounts and through-bolts as necessary.
- If possible, the sealant should be allowed to cure for a period of hours before the engine is started. Once started, let the engine warm up at idle and then shut it off.
- Check the pan carefully around the seam for any sign of leakage. If any leakage is found, do not attempt to cure it by tightening the pan bolts. This usually aggravates the leak rather than curing it. The pan will need to be removed and resealed.