The cooling system should be the first thing you check. Of all the things that go wrong with the BMW 5 Series Touring, this is the most likely. Take the car for an extended test drive and monitor the engine temperature carefully. Check under the bonnet to see if there are any leaks, and quiz the seller.
The next most likely reason for a visit to the workshop is dodgy electrics, so make sure that everything that's meant to work does so.
The axle and suspension systems are the third main area to be aware of, although you're far less likely to have a problem here than if you bought an E-Class or A6. Listen for creaks, groans and thumps, particularly from the rear where a hard-lugging life shows up with saggy shock absorbers.
All in all, though, the 5 Series Touring has proved to be a pretty tough customer.
Page 3 of 4