Need advice for my 2010 LaCrosse

[Pops2010]

About a year ago before my grandfather passed away, he gave me his 2010
LaCrosse CXS. It has all the bells and whistles aside from the heads up display. It only has 27,850 miles on it. I’ve driven it maybe 1,500 miles this year. He told me before he passed NOT TO DRIVE IT TOO MUCH.

Now here are my questions:

1) It shoots out black smoke for about 10 seconds when it’s started. I posted here a while back about that and everyone said that it was normal. But not it seems to shoot out a little grey smoke when cold. Is that normal?

2) The day of his funeral, it started telling me in the DIC that the car wasn’t in park when I turned off the car and put it in park. I have to turn the car on move the shifter and turn it off sometimes to get it to go away. The dealer said that they can’t diagnose unless I bring it in when it’s happening. That isn’t easy. Any idea what it could be?

3) I noticed a huge difference in gas mileage when I put premium in. Does it have to take premium. I am confused by the manual about this.

4) Does it take the dexos synthetic blend oil? My 2015 and 2016 both took that oil. But I can’t find anything in the manual to tell me.

5) He always had the oil changed 2 times a year even if he didn’t drive it more than 1,000 miles. Should I do the same?

6) Is it OK for the car to sit and not drive often? Everyone keeps telling me that these things are happening because it’s not driven.

7) Any recommendations for a good swirl/clear coat scratch remover? I paid $300 to have the exterior buffed and waxed. He told me that it would get the swirl marks and light scratches out. It didn’t even come close. I’ve used Adams and Groits. But I was looking for something to get those surface scratches out.

thanks in advance!

 

[Mad*Max]

I'll answer some - it uses conventional oil and once a year is sufficient if you are not driving much.

 

[MelsRegal]

1) It shoots out black smoke for about 10 seconds when it’s started. I posted here a while back about that and everyone said that it was normal. But not it seems to shoot out a little grey smoke when cold. Is that normal?
Do you have a check engine light on?

2) The day of his funeral, it started telling me in the DIC that the car wasn’t in park when I turned off the car and put it in park. I have to turn the car on move the shifter and turn it off sometimes to get it to go away. The dealer said that they can’t diagnose unless I bring it in when it’s happening. That isn’t easy. Any idea what it could be?
They didnt consider that the neutral safety switch might need to be adjusted?

3) I noticed a huge difference in gas mileage when I put premium in. Does it have to take premium. I am confused by the manual about this.
Page 8-48 and 8-49 of owners manual. If you have the 6 cylinder engine you should be using 91 unless it is not available. You do not want spark knock at any time.
http://www.vadengmpp.com/owners-manual/buick/2010-Buick-Lacrosse.pdf

4) Does it take the dexos synthetic blend oil? My 2015 and 2016 both took that oil. But I can’t find anything in the manual to tell me.
It would be best to use a 5W30 synthetic that meedts dexos requirements.

5) He always had the oil changed 2 times a year even if he didn’t drive it more than 1,000 miles. Should I do the same?
Change it once a year if you drive less than 7,500 miles per year.

6) Is it OK for the car to sit and not drive often? Everyone keeps telling me that these things are happening because it’s not driven.
It should be driven at least once a month other than winter.

7) Any recommendations for a good swirl/clear coat scratch remover? I paid $300 to have the exterior buffed and waxed. He told me that it would get the swirl marks and light scratches out. It didn’t even come close. I’ve used Adams and Groits. But I was looking for something to get those surface scratches out.
You need to use a liquid light compound on it to get surface scratches removed.

 

[G-261501]

Thanks so much for your replies! You guys have answered all of my questions!