The camshaft thrust plate perimeter seal forms a seal between the camshaft thrust plate and the gear case cover. If the seal should require replacement due to leakage, the seal can be replaced without removing the cylinder head. The following procedure should be used if the perimeter seal requires replacement.
Repair or Replacement of Thrust Plate Perimeter Seal
To determine if repair or replacement of the thrust plate perimeter seal is necessary, perform the following procedure. See Figure
Flowchart for Repair or Replacement of Camshaft Thrust Plate Perimeter Seal
Removal of Thrust Plate Perimeter Seal
Remove the thrust plate perimeter seal as follows:
Remove the air cleaner and charge air cooler ducting from the turbocharger and air intake manifold. Refer to section
If the upper radiator hose prevents removal of the valve rocker cover, drain coolant into a suitable container until it is below the level of the thermostat housing outlet. Then disconnect the hose from the thermostat housing. Refer to section
Using LPS Contact Cleaner or equivalent residue-free solvent, clean the gear case back/thrust plate area to improve visual access to the seal area. Wipe the area dry with paper towels.
Using an appropriate marker, scribe a vertical locator line across the gear case and the back face of the camshaft thrust plate. This will ensure proper positioning of the thrust plate during reassembly. See Figure
Camshaft Thrust Plate Clearance
Using the square hole in the middle of the crankshaft pulley, rotate the crankshaft to align the lightening holes in the camshaft drive gear with the camshaft thrust plate mounting bolts, providing access to the bolts.
Using an appropriate marker such as a grease pencil, mark the gear teeth. This will ensure proper cam timing during reassembly.
Insert the shoe of the camshaft drive gear torque holding tool, J 35652
, through a lightening hole of the camshaft drive gear. See Figure
Installation of Camshaft Drive Gear Torque Holding Tool
Using the 3/4 in. square hole in the center of the crankshaft pulley, bar the engine over slightly so that the bolt holes in the holding tool align with the access cover bolt holes in the gear case cover.
Install the camshaft drive gear torque holding tool, J 35652
, to the gear case, engaging one of the lightening holes in the camshaft drive gear. Use two of the access cover bolts to secure the tool to the gear case cover.
Using a long 3/4 in. drive breaker bar and a 27 mm impact socket, remove the camshaft drive gear mounting bolt. Discard the bolt.
Remove camshaft drive gear torque holding tool J 35652
from the gear case cover.
Insert a clean shop towel into the gear case opening to prevent removed bolts from falling into the gear case.
Do not allow bolts or the shop towel to fall into the gear case. Failure to remove loose bolts or the shop towel from the gear case may result in severe gear train damage at engine startup.
Remove the three (current) or two (former) camshaft thrust plate mounting bolts carefully to avoid dropping them into the gear case. Refer to section
Reverse camshaft gear pilot tool J 35906
by turning it 180 degrees and install it to the camshaft drive gear access opening using three of the access cover bolt holes.
The J tool number should face away from the engine and the hub end of the tool should be inside the access hole. Tighten the three tool retaining bolts.
Engage the puller bolt in the threads of the camshaft drive gear hub until the bolt is tight. Turn the bolt clockwise, pulling the thrust plate towards the front of the engine approximately 6-7 mm (1/4 in.) until the camshaft hub contacts the J tool and the perimeter seal is clearly accessible. The gap between the end of the camshaft and the thrust plate should be wide enough to permit the perimeter seal to pass through.
Using a flat-bladed screwdriver on the side of one of the camshaft lobes, lever the camshaft back and away from the thrust plate.
Using a hook-end pick, J 39227
, reach into the thrust plate bore in the gear case, hook the perimeter seal, and pull it off of the thrust plate. Pass the seal between the thrust plate and camshaft and discard. Pull the diamond seal from the thrust plate groove and discard.
Inspection of Thrust Plate Perimeter Seal Groove
Inspect the thrust plate perimeter seal groove as follows:
Rotate the thrust plate by hand and visually inspect to make sure all seal material is completely out of the seal groove. If necessary, use a work light or flashlight to thoroughly inspect the groove.
Wipe the groove clean after inspection.
Installation of Thrust Plate Perimeter Seal
Install the thrust plate perimeter seal as follows:
Failure to install seals properly, failure to install new, dry (no lubrication) bolts where required, or failure to tighten bolts to the required torque using an accurately calibrated hand torque wrench may result in bolt loosening and loss of clamping load, which may cause severe engine damage.
Do not use RTV or any other type of sealant on the thrust plate perimeter seal. Application of sealant will prevent proper seal crush (flow), which may result in seal leakage.
After passing a new perimeter seal between the thrust plate and cylinder head, carefully install it in the thrust plate perimeter groove with the ribbed edges against the sides of the groove and the beveled edge facing out.
The former thrust plate perimeter seal was redesigned to provide greater reliability and less susceptibility to twisting during installation. See Figure
for design configuration.
Thrust Plate Perimeter Seal
Failure to properly seat the perimeter seal in the thrust plate groove will result in seal damage. If the seal twists at initial installation or when pushing in the thrust plate, the seal can be cut and damage will result. Any seal damage can result in seal leakage during engine operation.
Rotate the thrust plate by hand and feel the seal to ensure it is fully seated in the thrust plate perimeter groove. If any ribs are felt on the outside edge, the seal is twisted and must be adjusted. Apply Super Lube to the inside bore of the gear case housing and not the seal.
When pushing the thrust plate and seal into the gear case, the seal may appear to twist. Do not be concerned because it is only rolling a little. As long as the seal was not twisted when initially installed, the seal will straighten itself out because its profile is designed to resist rolling.
The former two-bolt thrust plate face seal was redesigned to provide superior oil sealing characteristics. See Figure
for design configuration.
Two-bolt Camshaft Thrust Plate Face Seal
The current thrust plate uses a three-bolt design, as of serial number 6R352129.
Inspect the thrust plate face seal groove to ensure all seal material is removed. Clean the face seal groove with LPS Contact Cleaner or equivalent residue-free cleaner. Do not use mineral spirits, since this will leave a residue.
Wipe and dry the area thoroughly with clean paper towels.
To avoid injury from flying debris when using compressed air, wear adequate eye protection (face shield or safety goggles) and do not exceed 40 psi (276 kPa) air pressure.
Always bow out the cam cap bolt holes in the cylinder head before applying sealant and installing the cam cap. Failure to observe this step may cause lubricating oil trapped in the holes to push the sealant away from the cap when bolts are installed, resulting in a leak path.
For proper adhesion of the sealant at the cam cap/cylinder head joints, this area must
be completely cleaned and all residue removed before new sealant is applied. Clean the cylinder head and bearing cap contact surfaces thoroughly with LPS Contact Cleaner or equivalent residue-free cleaner. Wipe dry with clean paper towels.
Failure to clean surfaces completely and remove all residue may result in improper gasket eliminator application, which may cause oil seepage during engine operation.
Do not use RTV or any other type of sealant or spray adhesive on the camshaft diamond seal. Application of sealant or adhesive will prevent proper seal crush (flow), which may result in seal leakage.
Camshaft thrust plate face seals are not reusable. When replacement of a perimeter seal or removal of the camshaft is required, a new camshaft thrust plate face seal must
Install a new seal in the thrust plate, making sure it is securely seated in the thrust plate face seal groove.
For engines built after May 1999, use sealant 23525918 (50 mL) or 23525919 (330 mL) in the two diagonal groove cuts of the front bearing cap only. For engines built prior to May 1999, apply DDC gasket eliminator 23523064, or equivalent, to the joint surfaces of the number 1 camshaft bearing cap. See Figure
. To help ensure proper adhesion of the gasket eliminator to the bearing cap, do not apply oil to the number 1 cam bearing or journal before installation of the bearing cap.
Gasket Eliminator Application
When replacing the number 1 cam cap on engines with serial numbers between 06R0295500 and 06R0301875, the depth of the cam cap oil passage seal recess in the cylinder head must
be measured before camshaft cap installation. See Figure
1. Bearing Cap Stud Seal
5. Bearing Cap Oil Passage
2. Bearing Cap Stud
6. Oil Passage Seal Ring
3. Cylinder Head
7. Shim (If Required)
4. Camshaft Bearing Cap
Cross-sectional View of Cylinder Head and Camshaft Bearing Cap
Failure to install the shim under the seal when cam bearing cap seal bore depth is more than 3.04 mm may result in oil leakage around the seal during engine operation.
If bore depth is not within 2.64 mm - 3.04 mm, seal shim part number 23521153 must
be installed under
the square cut ring seal to provide proper sealing.
With a new square cut seal (and shim, if required) installed in the cylinder head oil passage seal recess, replace the number 1 cam cap. Install a new cap stud seal (part number 23521111) onto the flange of the camshaft cap stud, then thread the stud and the camshaft cam bolt into the cylinder head. See Figure
. Alternating back and forth, torque cap stud and bolt progressively to 128148 Nm (94109 lbft).
Loosen the large center bolt of tool J 35906
until it almost disengages from the camshaft hub.
Align the dowel on the camshaft with the cam hub. Push rearward on the tool J 35906
bolt while centering the thrust plate in the gear case bore and observing the alignment marks made previously on the thrust plate and gear case.
Install a metric bolt and washer in a gear case cover bolt hole next to the access hole.
To ensure proper camshaft-to-thrust plate alignment, the scribe marks on the gear case and thrust plate must
be aligned before the thrust plate is reinstalled in the gear case.
Carefully align the scribe marks on the thrust plate and gear case. Then, using a flat-bladed screwdriver or pry bar placed on the bolt washer and working from side to side, lever the thrust plate back toward the camshaft. With the thrust plate securely installed in the gear case, remove the metric bolt and washer carefully to avoid dropping them into the gear case.
Improper installation of the camshaft thrust plate bolts may result in thrust plate bolt stretching or breakage. Bolt stretching may result in an inaccurate torque. Bolt breakage may cause severe gear train damage.
Remove tool J 35906
. Carefully install new, dry (no lubrication) thrust plate mounting bolts through the thrust plate and into the cylinder head and No. 1 camshaft bearing cap. Using a 13 mm socket and an accurately calibrated hand torque wrench, torque the bolts alternately and progressively to 30 - 38 Nm (22 - 28 lb-ft). To avoid excessive tightening and possible bolt stretching, do not use an air wrench, since this may not provide an accurate torque.
Always use a new bolt when replacing the camshaft hub. The camshaft retaining bolt is considered a single-use item and cannot be reused,
regardless of apparent condition. Reusing this bolt may result in excessive bolt stretch, which could lead to loss of bolt torque, hub loosening, and severe engine damage.
Coat the threads and underside of the head of the camshaft drive gear-to-camshaft bolt with International Compound #2. Check the marks previously made on the gear teeth to ensure proper cam gear timing. Install the bolt to the camshaft, finger tighten.
Only tool J 35652
should be used to hold the camshaft drive gear stationary while loosening or tightening the camshaft drive gear-to-camshaft bolt to prevent component damage.
The camshaft should be held in place while starting the camshaft drive gear-to-camshaft bolt, to prevent disengaging the camshaft dowel from the thrust plate hub, requiring disassembly and timing of the camshaft.
Insert tool J 35652
through a lightening hole of the camshaft drive gear.
Using the 3/4 in. square hole in the center of the crankshaft pulley, bar the engine over slightly to position the camshaft drive gear holding tool so that the bolt holes in the holding tool align with the access cover bolt holes in the gear case cover.
Install two of the access cover bolts to secure the tool to the gear case cover.
Ensure any residual oil is removed from the dowel face of the camshaft and mating hub before installing the drive gear.
Apply a light coating of International Compound #2 to the camshaft drive gear mounting bolt threads and the underside of the bolt head. Using a 27 mm impact socket and suitable torque wrench, torque the camshaft drive gear-to-camshaft bolt to 75 Nm (55 lbft). Then turn the bolts clockwise 120 degrees (two flats of the bolt head) to achieve the required torque.