Un-Flood my old Super Duty

BJWhite2003 · Nov 9, 2025

Last year just before Hurricane Helene hit NC, we had another storm (PTC #8) that dumped a ton of water in a very short amount of time. Something to the order of 20ish" of rain (potentially more) in like 12ish hours. I won't get into all the details of that event again...but I have a '99 F250 (6.8L V10) that was impacted by that event as well. This is my first real "big boy" truck, so I have some sentimental attachment to it and I'm having a hard time justifying getting rid of it. With all that said...the water didn't get much higher than what is pictured here. This truck had sat for a long while before this event and wasn't started very often, but with some love...it would usually start and run. I've talked to a few folks and gotten a bit of a game plan put together but wanted to expand my audience a bit.

I'm going to make the assumption that the truck was in water for approx. 12-hrs from this time it rose to the time if fell.

I'm a "make a list" type of guy. Help me make a list of what actions I should take to revive this truck. Obviously, I want to make sure the engine will run before really doing anything more to it. I'm hesitant to put a battery in it and turn it over as I know if water got into the engine, that would for sure ruin the engine. So, help me out with what I should start with. I'll try to edit this and keep the list updated based on the feedback. I'll kick us off...

~~Attempt to Turn by Hand (breaker bar) (consider pulling spark plugs first)~~ - Complete. 2+ rotations by hand. No issues noted.
Oil Change
Fuel Tank (Drain/Clean)
Fuse Boxes
Chassis Grounds
Trans Flush
Transfer Case Flush
Front/Rear Diff
Wheel Hubs
Shocks

Thanks for your help and input!

Admins - I wasn't sure where to put this thread...so I figured since it's a Super Duty, it would fit here. Feel free to move it wherever it should be.

Vermonster · Nov 9, 2025

I think it's ok to have it under this - it's not 100% off-topic - so

Engine oil, as you stated, but also the front and rear diffs. I am not sure if/where they have vents, but they probably do and are filled with water.

I would drop the tank and drain/clean/refill.

Do you think the water ever reached anything electrical? Towing wiring and taillights look suspect at this time. I would check those out.

Cool rig! I understand the sentimental attachment.

InsanePyro · Nov 9, 2025

Definitely FLUSH the transmission, god knows where water is in there and gravity won't necessarily get it all like the engine or a diff.

Canyon Trekker · Nov 9, 2025

Since it is a 99, wheel seals may also have intrusion. Pull the wheel hubs off to check for intrusion. If you see water, dismantling and re-greasing bearings may be in order. Shocks are likely no good, would be a good opportunity to remove and check them out or replace. Check the fuse box, any water, make sure you check for corrosion. As a rule, check all wiring attached to the chassis and reconnect them if they appear to have any discolor to them. (Grayish color) Use a water penetrant on chassis connections. Check that the springs still have the friction pads; if not, they may start squeaking. Sometimes a simple lubricant can calm this down. Parts are available for this series of truck everywhere and generally are not too expensive.

I had a 99 F250 that I loved and hated to part with after I bought my Tremor, but it went to a very good friend who practically uses it every day. I took great care of that truck and replaced most every part mentioned above and virtually every moving part in it over the 20+ years I had it. If you decide to keep this, a lot of TLC will make it great.

Good luck.

BJWhite2003 · Nov 9, 2025

Thanks so far. List updated. I want to focus on getting the engine squared away first. If it doesn't run, then nothing else is worth the investment. The engine bay fuse block is up pretty high, so I feel that one is safe. The fuse block under the dash is probably high enough from what I can tell.

FuelTankReInforcedSkidPlt · Nov 9, 2025

Transfercase too since looks like your whole frame was under.

I would try to turn it over by hand at first, its hard to tell but possibly your whole exhaust system was under water for for an extended period of time without it running.

If it doesn't turn with an breaker bar, you might have to remove the spark plugs.

BJWhite2003 · Nov 11, 2025

Good points. Added T-Case Flush and Manual Turning by Hand to the list. Re-Ordered some items as well. Trying to do this in a logical sequence, so I don't waste too much effort. Frame was definitely in the water. So was the exhaust...but that needed some love before all this, so it would have needed replacement regardless. The water was high enough to impact the truck from probably 1000 to 2200, so we'll call it 12-hrs. Luckily, I think the engine was high enough that if (when) the exhaust filled up it may not have back filled the cylinders...But I could be wrong.

If I am wrong and some exhaust valves were open (very probable), would I trap water in those cylinders if I started to manually turn the engine over? I'm dreading pulling 10 spark plugs on this beast...I don't think the rear 4 are easily accessible...if I remember correctly.

FuelTankReInforcedSkidPlt · Nov 11, 2025

Exactly you would trap water in those cylinders, and cranking it with the starter could bust teeth as it would hydro lock. Then that's an even bigger job separating the transmission and the engine.

Ideally you get 2 rotations by hand and know you don't have to pull the plugs.

BJWhite2003 · Nov 14, 2025

Alright...it took a little bit of effort, but I got 2+ rotations on the crank bolt. I could hear liquid moving, but I'm assuming that was engine oil. The only real resistance felt was what I assume was the compression. Once I released pressure from the long handle, it would almost "bounce" back. Then no resistance when I reset and continued on. So engine is not locked up and since water is not compressible, I'm going to assume no water in the cylinders. Huge relief for me!

I also took some time to get ride of a bunch of dirt dobber nests and wasps nests. I checked the oil...looked ok...not milky, nothing unusual. It was pretty dark and a little low. So sounds about right in my mind. I checked the trans fluid....again, looked ok...but I'm not quite sure what watery fluid would look like, but I do plan on doing a fluid change before driving.

Water definitely got into the cab, but doesn't look like a lot. But that's an issue for a much later date. My rear half-doors are non-functional by the exterior handles. I forgot to check the interior handles, but I think the internal mechanisms are broke or have come loose thus not allow the handles to work correctly. Problem for another day. Also got the tailgate dropped...with some persuasion...going to need some all around love for sure once I get the engine running halfway decently.

Until next time...

Oil Check