Oil
Posted: Sat Aug 29, 2009 9:08 pm
Will semi syn oil ruin the seals?
Unless you just rebuilt the engine stick with conventional. Suddenly putting synthetic into a 35 yr old truck that was built for SAE 30 (that's not even multi-grade!) oil is a bad idea!
Mine started instantly leaking at the seals with synthetic. Also, the detergents in synthetic oil released a ton of built up sludge in the crankcase... seemed like a good idea at first but it's not good to suddenly "flush" all of it out all at once. I have a problem with my oil immediately turning thin and black after oil changes now due to the sludge release. Before using synthetic, my oil would remain amber-colored for hundreds of miles before gradually turning black. Now with the "sludge release" issue, my fresh oil only lasts a few days before turning black. I think that a couple more flushes with conventional oil (and new filters) will bring back the conventional oil characteristics that I once had. I have had to change my oil every month due to synthetic/sludge contamination.
This is of course a debatable topic.