Solventborne filler comprises at least one alpha,omega-hydroxy-functionalized oligoester which possesses an OH number of 30 to 160 mg KOH/g, a theoretical carbon-carbon double bond content of 1 to 3 mmol/g, a number-average molecular weight of 1000 to 3000 g/mol and a weight-average molecular weight of 2800 to 10 000 g/mol, moreover, the sum of the weight percentage fractions of all the alpha,omega-hydroxy-functionalized oligoesters being 0.5 to 10 wt. %, based on the total amount of the solventborne filler. Also provided are a multicoat paint system, a process for producing a multicoat paint system, and use of the above-designated alpha,omega-hydroxy-functionalized oligoester in solventborne fillers for improving adhesion.