I know this has probably been addressed, but since I can't search....

Do these oil additives work?

I was about to have my 3K oil change (going on 60K on my 99GLE) and the choad behind the counter tried getting me to purchase their "deluxe" package which consisted of

1) some sort of engine cleaning,
2) some additive like slick 50 (it had those fill in the gaps on the metal chart)
3) oil change

all for $45

Considering they were 40 mins late on my appointment, I decieded that was the last straw and got the hell out of there.

So far, I've been following the manual scheduled maintenance. Is that all I really need to do?

 

YOu don't have to search but you at least attempt to LOOK. Fluids/lubricants section