The interactions between the different type polyisobutylene (PIE)-succinimides and other engine oil additives as antioxidants and dispersants with high TBN (Total Basic Number) were investigated. Based on the thickening and antiwear efficiency and FTIR spectra of the additive-oil solutions strong interactions were demonstrated. Because of their basic polyethylene-polyamine groups the PIB-succinimide were able to build stable associates with Ca-salicylate and zinc-dialkyl-ditiophosphate type additives. Due to this interactions extra thickening and antiwear effect of the oil blends were achieved.