I accidentally drove my car (Nissan Sentra 04) through a flooded street (about 2 feet) of water at about 45 mph and it came to an abrupt stop after some rough hesitation. I tried to start the car several time with no success. I have comprehensive insurance on my vehicle so my insurance company towed the vehicle to a repair facility. Now the repair facility and my insurance adjustor are telling me that the car suffered a blown head gasket and it was because the car overheated not because of the flood. I called four different mechanic shops and all of them told me that a blown head gasket can in fact occur from this incident. They gave me a few examples to support their theory: water entering the engine through the intake can damage many parts of the engine or forced water could have damaged the radiator fan which in return overheated the car and blew the head gasket, etc. Also, the repair facility my car is at said all they did to diagnose the vehicle was removing the spark plugs (1/2 hour job). They said once they saw coolant (an ASE certified mechanic I spoke with questioned how in fact do they know it was coolant) coming from the plugs they came to their conclusion. Many ASE certified mechanics have told me that the shop my car is currently at did not diagnose my car properly and the flood could have blown my head gasket (because of many factors) and other parts in the engine (pistons, rods, etc) which can appear after a more in depth diagnosis. Please advice. Thank you in advance.
Please remember that we are like a computer system, garbage in garbage out. We work on information provided and if any information is incorrect, the answer would be according to it.
I don't agree that the engine has a blown gasket. The engine had been hydro-locked, meaning water had gained access to the cylinders causing at least one or more connecting rods to be bent.
The vehicle requires more than a head gasket job and once the cylinder head is off, you would be able to see what needs to be done. My bet is you definitely need to rebuild the engine.
Whomever did the diagnosis did not do a good job. Anybody who says a blown head gasket can occur from such a situation don't seem to be professionals. If possible let the insurance company knows you want a different shop doing the job.