don't run the engine,drain engine oil and replace filter ,add a silicone diesel addative to the engine oil ,this will lubricate all friction surfaces,and help to displace moisture before the engine oil gets into the key areas. I have used STP on several occasions once on a fleet of flooded vans that were stored .another thing to remember is are you going to drain the tank and flush out all associated lines .remove exhaust ,check air filter compartment ,.the latter is probably not necessary if the engine was running and did not cut out whilst in the water.you also faild to mention if your van has a turbo fitted ,daily, its possible there is moisture in the intake.
mech monster
November 2011