On my 2000 EB, I change oil every 5k or so, I have about 51000 on it now. This December, I added ProLong to the oil right after the winter LOF. I had done some research on additives, but had not found any really negative technical articles on ProLong, although there were several bad reviews on the other additives out there. Some of it is snake oil and some can provide nominal protection, but it's not really what it's cracked up to be. I wanted to use it to have something covering internal parts of the engine during cold startups, as I could here a slight valve clatter at startup, but it goes away after warmup. I just worry that those parts aren't being protected and it seems reasonable that a thin film of additive could do it. Couple weeks ago, while searching this forum, I found a couple negative posts on ProLong. I'm not a tribologist (oil scientist), but I can't really tell what's bad about these products other than exorbitant cost keeping it up with "booster" amounts after your next oil change.

Anyway, my questions are; I think to be safe, I'll want to go back to just plain oil changes with no additive, as additives (and ''booster" amounts) are just extra cost in my mind. I just had the Spring LOF done. Will continued LOF's completely or mostly flush out the ProLong? What about if I decide to go with synthetic at this stage of the engine's life? I'm thinking about going to Mobil One. What do members of this forum recommend and advise? After a couple of flushes/LOFs, will the ProLong be flushed out? And, can I go to synthetic from here?

Thanks in advance - ya'll are a great forum. I check it out everyday for news on my EB, it really helps.

 

I have a99. When I switched to Mobile one synthetic, I used a can of flush before I changed the oil. I use Mobile one in everything now. If you want more info go to the oil forum and do a search.