2006 Envoy Denali engine woes

[neila452]

Dear Envoy Forum Readers,

I have a 2006 Envoy Denali with the 5.7 liter engine and 52K miles. Bought it new in Dec. 2005.

A year ago in 2010, I suddenly started having engine problems. When first started, it suddenly started blowing smoke out the exhaust, accompanied by a ticking noise and rough running. At first, it would smooth out quickly and be fine. Two or three more incidents and it worsened; it would not smooth out.

Within a week of the first occurrence, I took it to the dealer. They kept it total for about 2 weeks. After a few days, dealer service agent called and said the engine needed a partial rebuilding consisting of new lifters, valve seals, and head gasket on the left bank of cylinders. He said that the mechanic would like to put new valve seals on the right bank, but the extended warranty representative (not GM extended warrant) refused to authorize it. The total bill was $2100 of which we had to pay $280. After the repair, the car was fine.

Then, in late June we took it on a several hundred mile vacation trip. Ran fine the whole way until the day after we arrived. Then, on the way in to town I began noticing the lifters ticking loudly. Stopped and checked the oil level; it wasn't even touching the dipstick. There was an oil change place nearby. Got a complete oil change using Mobil 1 synthetic. No further problems until we arrived home.

Checked the oil a few days after arriving home (about two weeks after the vacation oil change) and found it was down more than a quart. Had Valvoline Oil Change do it (who we always use), putting in synthetic oil again. Runs fine. Probably have put ca. 1500 miles or less on it since then.

Question: Is it time to get rid of this car? Am I likely headed for major engine problems? I maintain the car well; it is like new inside and out. Oil changed every 3000 miles. I would really appreciate some advice from those of you who know more about this 5.7 liter variable displacement engine than I do — I don't know much.

Thank you all so much.

Neil Anderson

[maxwedge]

Excess oil consumption is an indication of internal engine problems, I would have the pcv replaced and checked, cheap job, monitor the consumption, you should get at least 1500 miles to a quart, some would say more. Post back the results of both suggestions.

[jassedai]

I have the exact same problem. Dealership was unable to find an issue but did send me home with reasonably priced oil change and free monitoring every 1,000 miles. We'll see what happens!