The move comes nearly a year after the FTSE 250company ushered in a new group CEO - former Euro Disney chairman André Lacroix.
Inchcape wants to highlight recent growth and its ambitions for further expansion.
The move puts in jeopardy The Hogarth Partnership's six-year relationship with the company.
Hogarth has been invited to repitch and Inchcape IR manager Kate Messum said no date has yet been set for a confirmation of an appointment.
The hired agency will report to Messum and the company's board.
Inchcape has been highly acquisitive during the past year. So far in 2006 it has bought Norwich-based Lind Automotive's 21 dealerships for £108m, and forked out up to £38m for a majority stake in St Petersburg's Axel Car Toyota and Lexus car dealership.
The Lind deal made Inchcape the UK's biggest BMW and Mini seller.
Lacroix replaced Peter Johnson as CEO in January and immediately earmarked the fast-growing Russian market - where foreign-brand car sales are rocketing - as having major potential for Inchcape.
Lacroix said he expects foreign brands to account for half of all new car sales in Russia by 2010.
In March, Inchcape announced plans to launch a joint venture with Russia's Independence Group of Companies, based on two Toyota retail and service centres in Moscow.
Lacroix has announced plans to have a major foothold in ten countries within five years, adding Russia and China to its strong portfolio in markets such as Britain, Australia, Belgium and Hong Kong.