Land Rover Repair: 99 LAnd Rover Disco II Driving Through Severe Flood Misfires, blown head gasket, detour signs

Question
QUESTION: John,

It has been raining for a 2 weeks straight. Roads are flooded and detour signs everywhere. I figured this would be a perfect time to test my 99 Discovery II. Drove through 4 blocks of water appx. 1-2 feet high gunning it at 10-30 MPH. All the sudden it struggles to go (gassing it and its getting weaker) and the check engine light comes on and it stalls! I turn the check engine light off and continued my fun. But I'm gunning it and its losing power and the light keeps coming on. Fine. I'll wait until tommorrow. Went back to the flooded roads and parking lot. Same thing! Only this time the check engine light starts flashing! Codes are 1300 and 0402/0404. I just spent $6000.00 in repairs on 1/1/9 from a misfire/coolant/oil mix leak. Valve job, new upper heads, new radiator, termostat, spark plugs, new seals, the works. What is going on here? These cars are supposed to drive through lakes and rivers. Did I just cost myself another 6k?

I turned the check engine light off and it APPEARS to be driving normally... I hope nothing is wrong.

ANSWER: I hope nothing is wrong too.  It sounds like you got some of the wiring wet.  To prevent a recurrance, take apart every single electrical connection on the motor (many are under the vehicle) blow it out with compressed and, pack with dielectric grease, and reassemble.  That should take care of the problem.


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QUESTION: You mean stuff the grease inside the plugs/connections and sqeeze them back together with the grease inside? Ok.

I hope it's just the wiring too but now its misfiring (with misfire code) on the same cylinder that blew out (#2) in December and showing a MAF fault. I'm going to take apart the MAF and smell it for exhuast. The mechanic I hired on Craigslist told me thats how you confirm/check a blown head gasket.

Answer
Yes, exactly.  I mean blow the connections out and make sure they are dry.  Then pack in a squirt of dielectric grease, and stuff together grease adn all.  That prevents water intrusion.

It's certainly possible you ingested water and damaged a cylinder.  Sniffing the mass air meter does not confirm a head gasket failure.  If you have a fault on #2 I'd look at the injection and ignition in that cylinder, and even take a bore scope and look inside