Step 4. Valve Guides
Step 4. Valve guidesNote! It is very important to realize that there may be the presence of engine oil in the intake ports without an actual valve guide leakage. Using Automatic Transmission Fluid (ATF) for color differentiation is an effective way to verify if there is or if there is not a leak between the valve guide and the cylinder head. Cylinder head replacements should NOT be based on assumptions.
Valve guide leakage has been seen on vehicles with an engine build date before 040511B01272 (DDMMYYxxxxx). Valve guide leakage is most commonly found when a customer complains of excessive white smoke from the exhaust. However, these tests should be performed on all engines with oil consumption to be sure the valve guides are OK. These tests check if there is oil leakage between the cylinder head casting and the inlet valve guides.
Look at the spark plugs in Photo 4. If the valve guide is leaking in a cylinder, the corresponding spark plug will have more soot than the others. In the example in Photo 4, cylinder 2 is consuming oil.
Remove the cam cover and test each valve guide using ATF. The test below should be performed:
Note! Use safety glasses! Remove the valve tappets. Plug all but one intake port, all injector ports, and the PCV inlet. Starting with the intake port that corresponds to the spark plug with the most soot, apply air pressure to one intake port at a time using a plug similar to those found on emissions testers. See Photos 5 and 6, left. Look at the
base of the valve spring and check for ripples or bubbling in the ATF as you apply light air pressure. If the ATF ripples or bubbles, then replace the cylinder head.
Note that this test is only for the intake valve guides. If valve guide leakage is suspected and there is excessive white/blue smoke from the exhaust, then there is a possibility that the exhaust valve guide is leaking. In that case, the exhaust manifold should be removed and the exhaust port should be check for excessive oil deposits. If this is found, then replace the cylinder head.
AT THIS POINT PRIOR APPROVAL SHOULD BE CONTACTED fill out the form
found on the prior approval website and submit it before any repairs are made.