I use to spend quite a bit of time at auctions back in my trade days.
Closed auctions are for trade only which are the best auctions to attend to buy stock.
All fleet/lease vehicles end up being off loaded through auctions. Open auctions (open to the public) is also where the trade tend to dump the dogs they don't want.
Glass's guide is the bible of the motor trade http://www.glassbusiness.co.uk/ but still don't stop you from buying a dog in an auction 
this is why I tend to buy from the aa , as the vans have only ever had one driver , been limited all there lives , and are trackered to death which includes the drivers driving , also because they carry passengers so there maintained 100% as its the aas duty of care to keep there custmers safe while in there vans
I used the same logic when buying mine! 2008 Ex AA Vivaro - 3 months on timing chain snapped and lunched the engine, hope the transits are better
I don't understand some manufacturers (BMW, VW, Vauxhall, Ford) going back to timing chains. Timing chains rattled when they stretched and they wore the sprockets out. Owners believe they don't need to worry about timing chain maintenance like they did a cambelt, but yes they do.
If the timing chain stretches, the sensors pick up and engine issue and the ECU shuts the engine off. Vehicles are towed back to the agents for a computer upgrade that will give an additional tolerance factor. to get the vehicle going again.
This whole issue with cambelts is all about the waterpump. If a water pump bearing seizes up which they sometimes do, then a £15 part can destroy a whole motor,
What was wrong with the design of the 2.0 Pinto engine in my Ford Sierra 30 years ago? Cambelt in the inside, and external fanbelt that drove the water pump, alternator and airconditioner.
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