The 3.0L engines used in these vehicles utilize hydraulic lifters. No periodic adjustment is necessary or possible.3.4L Engines
See Figures 1, 2, 3 and 4
The valve lash should be checked and if necessary, adjusted every 100,000 miles (160,000 Km).
Tappet compressor tool T89P-6500-A and tappet holder tool T96P-6500-AH or their equivalents are required to perform this procedure.
- Disconnect the negative battery cable.
- Remove the valve cover. Refer to Engine & Engine Overhaul of this repair guide for the valve cover removal procedure.
Camshaft lobes must be directed 90° or more away from the valve tappet.
- Insert a feeler gauge under a camshaft lobe between the lobe and a tappet at a 90° degree angle to the camshaft. The intake valve clearance (cold) should be 0.006-0.010 inch (0.15-0.25mm) and the exhaust valve clearance (cold) should be 0.010-0.014 inch (0.25-0.35mm).
- If the clearance has to be adjusted, insert tappet compressor tool T89P-6500-A or its equivalent under the camshaft next to the lobe and rotate it down to depress the bucket valve tappet.
- Insert tappet holder tool T96P-6500-AH or its equivalent and remove the compressor tool.
- Direct a jet of compressed air towards the hole in the face of the valve adjusting spacer to lift the spacer off the tappet.
- Determine the size of the adjusting spacer by the numbers on the bottom face of the spacer or by measuring the spacer with a micrometer.
- If the spacer being used will not permit the specified clearance, discard the old spacer and replace it with a spacer that will permit the specified clearance. Make sure to install the spacer with the numbers facing down and that it is properly seated.
- Insert the tappet compressor tool and release the tappet holder.
- Repeat the procedure at each valve by rotating the valve as necessary.
- After all the valve clearances have been checked and/or adjusted, inspect all the valve adjusting spacers to make sure they are fully seated in their bucket valve tappets.
- Install the valve covers.
- Connect the negative battery cable. Refer to Engine & Engine Overhaul of this repair guide for the valve cover installation procedure.