How to repair a flood damaged vehicle
I have a 2004 GMC Envoy and I attempted to cross a creek in it and the water was deeper than I realized and as I pulled into the creek the engine stalled and I immediately tried to restart it but it would not even turn over. My first assumption was that maybe the water splashed up and got the alternator wet or something like that so I called for a rollback to come and pull me out. It took about an hour for the rollback to arrive and by the time it got there water had seeped into the floorboards approximately a foot deep. Parked it at my parents house and I let it set for about a week and had my parents neighbor who is a mechanic look at it. He said that there was no water in the oil or transmission so he tried to start it and told me that it acted like the battery was dead. Waited about 2 months and he went back over there with a battery booster and tried again and he said that all the lights come on like they are supposed to but still would not turn over. What do I need to do to get this vehicle running again?
Cars & Trucks - GMC
Answers & Comments
There is no set menu to recommissioning a "flooded" vehicle - in short, it needs checking over and whatever is found needing attention should receive the attention. When checking and making the list, every aspect of the vehicle should be considered from the headlamps to the tail lights.
We once recovered a flood damaged car and water had got in almost everywhere - even inside the engine management computer. It took a deal of time to remove all those electrical bits and pieces, dismantle them as far as possible and leave them to dry for a couple of weeks and then put it all back together again but not only did the car start and run again, no new parts were needed.
That was in the old days of analogue systems. Your car is probably fully computerised and employing digital electronics throughout which is an added complication - think what happens when your mobile phone gets wet. Digital electronics are more sensitive and more likely to self destruct if powered up while wet. It is very difficult to carry out tests on digital electronic components and systems without specialist knowledge and gear.
Putting all that aside for a while, I suggest you begin by removing, dismantling and servicing the starter motor and testing it before refitting and then ensuring the engine cranks by manually energising the starter solenoid. If that stage is ok but engine won't crank with the key you can assume there are electronic problems and begin testing; starting with the immobiliser.
The starter is an electric motor and they don't like being under water, replace the starter, spray penetrating oil on the parking brake cables. as soon as you get it started take it for a cruise and ride the brakes a little to heat them up and boil off the water so the springs and brake pads don't get all grungy. I hope this helps. Take care.