I was wondering what your guys view on using engine additives are. I have a 90 b12 with 146,000 miles on it and the engine is fillthy. I also had someone listen to my car start up and he said it sounds like I have sticky lifters( not sure what lifters even are) and I have a leak from the seal behind the distributor. I have been using semi synth for the last 6,000 to try and help out my engine a little. I have heard a lot about engine additives that clean out sludge and gunk and clean sticky lifters and recondition seals, but do they actually do anything? Also, would it possibly damage my car? If I have nothing to use I might try one because it's worth the money in my opinion to keep this car going as long as I can, but for anyone who has experience in this field what brand is the best and what sort of additive should I try. All opinions are welcomed.