WHAT CHANGED?
Q: I have a 2007 Suburban 5.3L two-wheel drive with 276,427 miles on it. I have changed the oil and filter every 3,000 miles since I bought it brand-new; initially, I used Pennzoil 5W-30 conventional oil and AC Delco oil filters. At 171,856 miles I switched to Pennzoil 5W-30 High Mileage oil because it was burning a quart every 3,000 miles and it was suggested by a mechanic to do this to maybe stop it. Some forums I looked at said the GM engineers knew the LS engine was doing this.
The temperature had always been at 210 during normal driving, but last summer it would run at about 220 when stopped at a red light and then go back to 210 when I started moving. At 263,221 miles I switched to Pennzoil 5W-
30 Synthetic Blend High Mileage because I was having trouble finding conventional high-mileage oil.
This past February it started running at about 220 to 222 again when
