How did you figure out it was the wrong oil? By the color?
When I took the car in..I mentioned to the service writer to make sure they used Mobil one..he stated that they didn't use Mobil one, but used a Citgo Product . I just assumed, being a dealer, that they knew what they were doing. I checked with multiple sources for Citgo Lubricants, including Citgo itself, and can't find anyone who has heard of citgo even offering a full synthetic oil that meets the GM4718M spec.
It turned out well...I took it to an oil change place near my house that I have been using for years, and who I trust, and explained the situation to them. They drained out the Citgo Oil, put in a new oil filter, and put in the Mobil One that I had brought with me. They told me .."no charge". That was a pleasent surprise
Valvoline is an excellent company.
My '87 IROC will run to 229 degrees before the 2nd electic fan comes on.
Valvoline is the ONLY oil that i have used that will last a couple of thousand miles before the oil pressure stops dropping.
My IROC has 205,000 miles on it and I use Valvoline HD Racing 20W-50.
I am sure their synthetic product must be good also.
The dealer in Raleigh charges $74.95 for an oil change using Mobile 1. $16 for labor, $9.55 for the filter element (seems low to me) and the remainder for the oil, $49.40. On a normally driven car, it will go ~10,000 miles between oil changes. This seems about right for a full synthetic. The stuff just does not break down, it just gets dirty!