I bought a '97 which was dropped partially into a lake, consequently due to thermal shock it blew the head gasket.
Truck has 229,000 miles........I just opened up the top end and brough head to shop.

I can say I AM IMPRESSED !!! After these many miles the amount of carbon is ridiculous, even the cylinders have still original pattern crosshatch from factory. Pushrods are clean, not much oil deposit, pistons have just a light coat of soot and that's it. Motor has NEVER been rebuilt !!!! Unbelievable !!!!!!

I had 2 6.5l Chevy, 1 Duramax, 2 Powerjokes Ford (both 7.3l thank godness) and this is my 2nd Cummins......I'll never, EVER get anything different, guaranteed, and I am looking out for another wrecked truck to put a Cummins conversion on my Suburban.

 

Cross hatch on the cyls, but good chances the bores wont be round.
I would be spending some money in magnafluxing before spending allot of money elsewere on that engine, these cyl heads dont need thermal shock from taking a bath to crack.

 

I am guessing it looked alot like this except the burnt piston?
I too was surprised at the little amount of carbon build up, and how well the cylinders looked on this engine with over 200k on it! too bad the 6th cylinder is fubared

 

dropped into a lake??? ice fishing i guess as not too many people pick em up with a helicopter and drop em into a pond.
my questions would be 1. Running or not when it went under? 2. if not running, how long had it been sitting when it went under?(cold,ambient temp engine or a warm engine?) 3. Completley submerged or a partial where there was not a chance for water to enter the intake tract of the engine? 4. was engine cranked over or attempted to crank over without draining oil and removing injectors? ( in case of water being on top of pistons and causing hydro-lock condition and possibly bending the con rods)
as you have the cylinder head off i would roll the engine over and look at each pistons relationship to the top of the cylinder block, if one is noticibly lower you have a bent connecting rod due to water being on top of the piston when it was on the power stroke of the combustion cycle or their being so much water in the cylinder and when it was on the exhaust stroke, even though the valve being open, the piston could not push out the water as fast as the piston was coming up.
I agree as was stated above, it does not take alot of thermal shock from an outside source to effect the integrity of a casting. money would be well spent in having things maganfluxed.
also, water injested into a running engine in small amounts will do wonders to the amount of carbon deposits inb a cylinder or cylinders. If one has ever blown a head gasket take a look at the cylinder where it was blown at, that piston and the valves for that cylinder are super clean. basiclly it is steam cleaning the inside of the cylinder. alot of other things go on also as some hot rod/racer guys may want to talk about concerning temps and combustion and compression.
if you feel good about everything and everything checks out to your satisfaction, i would clean everything up,(complete dissasembly would be best) new bearings in crankshaft and con rods, gasket set, good clean fuel source and try it, hopefully water did not damage the fuel pump.
I have worked on quite a few submerged dozers and hyd excavators that use the "B" series engine and they are a pretty tough engine. the only downfall is they are a non-sleeved engine.
everything from rotary bosch,rotary lucas ,inline bosch,inline nipondenso,inline diesel kiki.
the offroad market , as of this year is going to HPCR, they pretty much missed the CAPS system or for you on highway guys 98.5 to 2003, lol
good luck and let us all know how you do.
also take a good look at your push rods, a bent one has a good indication of something being on top of the piston that is not supposed to be there.

 

Thanks for the reply.

I don't know if engine was running when dumped and what height was water.

I had truck running, and running good for few miles, only issue I had was water in oil and viceversa, also coolant was bubbling a lot when running, and some evident blowby steam.
No rod noises, in fact it is very smooth and it starts as soon as I turn the key.
I am doing headgasked as a test, hoping it's nothing more serious.
SO far is looking good, there is no steam cleaned cylinder, I didn't see an evident sign of blown gasket, I will check oil cooler today.