Hey!! I'm a Magic Rear Seat!!
Anyway...
Had to drive through about a foot of static flood water yesterday & experienced a loud knocking at one point which I thought was either underwater debris or, rather more worryingly, sudden contraction of the exhaust system due to contact with cold water.
Today I have looked & am sure it was debris as the corner of the plastic shielding underneath has detatched & dropped down a bit. The local dealer said I may be able to fix it by pushing the fixings back in but he's off home now cos the local sewage works is about to flood & it would cause him a few issues!
Anyway, is there any chance of cold flood water that contacts the underside of the car causing damage through cooling bits like the exhaust too quickly?
Also what depth of static water should a Civic be able to get through? Any tips on the most reliable & safest way of getting through it too?