is there any oil additives that actually work? i did and intake manifold gasket and valve cover gaskets on my cadillac and lets just say, it wasn't as clean in there as id like it to be. all kinds of sludge in the corners and black crud everywhere. i cleaned up everything as best i could before i put it all back together, but i wondering if there was anything that would clean up everything i couldn't get to.

 

The best thing you can do is use a quality synthetic oil & filter. I would recommend Amsoil XL 7500 full synthetic and a Purolator Pure One filter. Although the oil is rated for up 7500 miles per change I only go about 4000. I have used it for several years and it does well in all applications especially during winter here in Minnesota. In addition I also use Prolong Oil additive every oil change, although this seems to help the synthetic oil is definately what does the trick.