Soon I will be adding MOS to oil of an 1989 Chevy truck 1/2 ton, it is the 5.7 liter engine with well over 200k miles on it. This truck is largely now only used when we get a lot of snow fall during my commutes. So it can sit around for a long time except that I do try and start and run it every 2 weeks and slosh the fuel around in it. Obviously it likely needs heads reworked, but i thought I would use some MOS and report my observations. Once again only one persons honest and unscientific report. YMMV Below is a video, my son shot for me while I fired it up,,, it had been sitting for about 2 weeks. In the video, you'll hear me ask my son if he's ready and he say's yeah.. I crank and start it and you'll see the smoke. [img]http://i1026.photobucket.com/albums/y330/jcxx75/th_20141214_125444.mp4[/img] Some time later this week, i plan to add the MOS, drive it to work, which will get it nice and warm as required by the instructions on the can of MOS. Will report back at some later date as I get a chance to make some observations. on edit: forgot to mention,,,I have pennzoil 5w-30 HM oil in it for about 500 miles more or less.