Possible Solution to the 4 CYC Rattle Issue
The other night i noticed some oil under the car. Checked it out with a flashlight and the entire area was coated with oil. Took it in for service the next day for this and i also brought up the noise where you will hear what sounds like a chain (which is the timing chain anyway) hitting a metal case when it in 4 cylinder mode. I knew there was a TSB about it where GM says no fix at this time. Anyway the tech found a major leak in my oil pan so when he dropped the pan he saw a piece from the timing chain tensioner just laying in the pan. It broke off. Maybe this is whats been causing the issue? Got car back today after that replaced everything of course and problem is gone. My suggestion would be, check your oil pan to see if someone is laying in it b/c if it is, they have to fix the rattling issue. The chain without this peice has slack in it and when in 4cyl mode it makes a rubbing noise.
Last edited by steveman0018; Nov 5, 2010 at 07:04 PM.


