All modern GM cars now are DEXOS recommended, even 2006 HHRs. It is not legal to require unless it is provided free. And, liker I said most semi-syn and full syn oils are DEXOS, the ones that aren't are the "boutique" brands that won't pay the fee.

 

So after replacing the tensioner, and a few days of listening at a cold start, the rattle is still there. While the cover was off, I didn't see any broken pieces of the guides, or anything that didn't look right. However I have noticed that the rattle noise doesn't seem to last as long now, and is almost, faster? If that makes sense.

 

Did you engage the tensioner? A quick tap of a socket extension 3/8 drive worked well.

 

Yes I did engage the tensioner.

 

Excellent!

 

After reading through several threads. I have have two questions:

1. If the tensioner went bad, would the chain become lose and then set off a CEL?
2. If a lose chain sets off a CEL, and I hear a rattle from the chain area, but don't have a CEL, is it safe to drive?

(I hear a rattle and am freaking out)
Thanks in advance!

 

I'm sure someone more knowledgeable will chime in, but if you hear a rattle I would definitely take off the valve cover and at least take a look at what could be going on before you drive it much.

 

X2^^^^^, hear a possible timing chain rattle, investigate, a loose chain means either a stretched chain or broken front guide or tensioner problems.

 

I had a local auto service place replace the timing and balance chains, and water pump.
The noise I heard was from a guide that was broken and the chain was grinding one of the bolts.
Thanks to everyone here for your help.

 

Dodged a bullet!