2008 Ford F-250 with a 5.4 Liter V-8 3-valve engine and automatic transmission.

Running down the road at 44-MPH. Pulling 5,000lbs. Engine died just after turning on the air conditioner. (Not sure this is relevant.)

Would not start. Turned the key…the starter would engage, but the engine would only turn maybe a quarter turn. Try it again…engine turns ¼. Try it again…and now it only clicks.

So, I…

-Replaced the battery. Same symptom. Will only turn the engine 1/4 turn.
-Replaced the starter. Same symptom.
-Checked oil. Clean. No Water. No gas smell. (200 miles since last oil change)
-Checked coolant. Clean. No Oil.
-Charged the new battery and tried again. Same symptom.
-Checked and cleaned all grounds and battery cables. Same symptom.
-Checked that the transmission is shifting though the gears. Seems fine.
-Removed serpentine belt. Check all pulleys, and accessories that are driven by the belt. Everything spins quietly and freely.
-I put the truck in neutral and tried to spin the crank pulley with a 2’ breaker bar. It wouldn’t budge.

Am I missing something? I fear the engine is seized or hydro-locked. If hydro-locked, wouldn’t I see signs in the fluids? Can the pistons be hydrolocked with fuel? Not sure what to try next.

Any guidance would be appreciated.

Tim

 

You may have a broken flexplate. I experienced the same symptom with my '06 Van last winter only difference was the truck ran fine one day, parked it and the next day the engine appeared to seize when I tried to start it. Breaker bar on the crank could not move the motor, but in working it back and forth I manage to get it free. It cranked briefly after that but seized again, worked the breaker bar some more and then the starter spun freely and didn't appear to engage the flexplate any more, so I changed starters but that didn't help so that is when I started looking at the flexplate closer and eventually discovered the real problem. Upon removing the inspection cover at the front of the trans I discovered I could push the flexplate back which isn't right, it had somehow become disconnected from the motor. Anyway after dropping the trans this is what I found, my guess is that with nothing centering the flexplate on the engine is would jamb on the trans case when I tried to start it.

 

My '04 3V locked up while pulling a trailer 200 miles from home. After it cooled it started and ran. It was a little over a quart low on oil. The engine eventually started but set cam timing codes. It got me home, with the solenoids unplugged. About 500 miles later the timing chains started smacking the cover. After tearing into the engine, I found evidence of poor oil pressure to the heads. On the passenger side, aluminum had melted and been extruded from under the camshaft, and most of the journal caps were finger tight.

It's running fine with a rebuilt engine, that cost me about $6,000 total.

 

you removed the belt, and did you try to crank motor with belt off ? I know you said you checked the pulleys, but also happened just when you turn on the AC.... I have heard of the clutch locking up and causing this problem.

 

Are the plugs out ? If not try that, it will answer your hydro lock, you won't be fighting any compression at all. . Yes I believe a bad injector can hydro lock it .
But really my gut says you may have valve to piston contact . If she jumped time far enough or dropped a valve . . So try that and come back .
If she has a bent valve /piston then my guess is a long block . You can look at her with a bore scope . Might as well drop oil pan and look for guide pieces and lower end damage .
Of course the a/c compressor seizing could have done this but you have belt off .Compressor could have provided jolt that broke engine part .
She should turn clockwise with plugs out and breaker bar ,I turned mine with a half inch socket wrench . . Try neutral as well as park . Maybe transmission has it locked up , I am weak on transmission . If you suspect tranny ,some other help on here will pop up .What does fluid look like ?
I would try marking and dropping drive shaft at one point . They are very finicky about going back exactly how they came out .
Sorry for your trouble , Me I'm at 176k , been fearful of an eventual trans failure so I have some shops in mind if I have to do it ,definitely no aamco .
Keep that tranny cool .

 

Gentlemen,
Thank you for the feedback. The broken flexplate is interesting. I'm hopeful it will be something like this...vs a new engine.

I did try to start it with the belt off. The symptom was the same. I'm a bit nervous about pulling the plugs. What year did they give up on the junk plugs that would break off?

Tim

 

Another new symptom to offer which may give credence to a flexplate issue or similar. Please excuse my ignorance with this new information. I am far more familiar with manual transmissions and their characteristics.

I turned the key switch on. I put the truck in Low gear. I pulled it with a forklift. I expected there to be resistance. There is none. I am able to pull it as if it were in neutral. Got off the forklift and was able to push the truck by hand. No resistance at all while in any gear. Is this right?

 

If it's an automatic, there are no gears unless the trans pump is turning. Without the engine running, there's only park and everything else is essentially neutral.

 

Anything manufactured after October of 2008 is what my research told me. Of course my 08 was just before that and broke one during the last tune up. My trusted mechanic of almost 8 years really stuck it me on labor. Using someone else now

 

If she's seized the plugs are a minor problem just have a lisle extractor on hand .
Well, pull oil pan and get a look at her from below . Get valve covers off . Look at each cyl with a bore scope ,you can get some cheap ones .
We would like to ride along as it always helps someone else also .
Then there always is the reman route . all of this will help if you decide to pull engine .