Motor stuck

[valleyduramax]

So I have had my 05 lly in storage for just about 3 years now. Was in process of doing some changes to it then due to buying a house and then married, it was put to side. Just got it back running a week or so ago and now have a potential major issue. Truck was running fine on a few short drives and idling. Decided yesterday to take it a bit farther as everything was working great. Truck just randomly shut off while I was checking a few spots for any leaks. Tried to refire but it would just roll and roll. Finally the engine rolled over maybe 2 rotations and stopped dead. Towed it home and just tried to start the trouble shooting. No codes at all and everything was fine according to gauges. I can turn crank 1 revolution either direction and it stops at same spot with serp belt off. It is looking like a stuck valve from everything I can see. No off noises or behaviour before sudden shut off. Brand new starter and batteries. Has anyone had this happen? Or possible areas I should look into before I tear into heads? I know I have to tear into it just looking for something I may have missed at looking into. I had no missing or leftover parts and all work done was external as I have a build thread in this forum.

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[torqued2dmax]

Was there any water in your water injection tank prior to test drive ? An LLY sitting that long you may want to do gaskets and studs anyway , this could be telling you something ! You might have caught it prior to real damage ! Good luck , let us know what you find !

 

[valleyduramax]

I don't actually have the water injection on it anymore. I have a modded stock turbo and then intake tube and y bridge. I knew that sitting that long could be a bad thing for it but it happened haha. Hope it's just a valve which will mean top end rebuild but probably time for studs and new gaskets anyway

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[clrussell]

I wouldn't hold your breath on a stick valve being the problem. But I've been wrong before

 

[Wikid]

Stuck valve would seem kind of unlikely. It would have to be stuck open and hit a piston and i wouldn't think that would stop a motor even at idle. Would make a good bit of noise too.

what does the oil look like? were you manually rolling the motor over right after?

was it the same fuel from 3 years ago? can diesel get to the point of not being able to fire? wonder if it filled a cylinder to the point it locked up.

 

[valleyduramax]

quick list of work done before first startup:

new power steering setup
new trans lines and cooler
water to air setup
new y bridge and tubing
modded turbo
new fluids for motor and trans
new starter and battery
all filters changed
fuel tank was removed and cleaned and new sending unit and different sump

symptoms now since complete:

-ran good since first startup about a week ago with no issues or noises
-fluids look good and all at correct levels
-sudden stall on Saturday when out for a quick test drive
-just cranked but no fire after stall which was tried about 4 times cranking for about 10-15 seconds per try
-then it rolled twice and suddenly stopped
-put socket on balancer bolt and motor spins either direction 1 turn and stops as though it hits something
-rad hose not hard and not loosing coolant
-oil pressure and engine temp were normal and no codes or anything
-original injectors with 260000km on them

I realize without tearing into it that its all speculation but i cant see it being hydro locked as it would be "springy" before stopping. Unless I am totally wrong about that. Would it be possible that trans could be causing a problem like this? I will post update once i get into the teardown.

 

[DAVe3283]

I've hydrolocked a Duramax, and it's not springy at all. If you pull the glow plugs out, that will show you if it is hydrolocked.

If a torque converter bolt backed out, it might hit on something and stop like you describe, but that's unlikely.

Let us know what you find.

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[valleyduramax]

Ok that's a good thing to know. i did try to get a glow plug out but of course it is corroded in the threads so it started to twist head off. So ill try to get them out and go from there. Also check into converter bolts but like I said, no off noises before no start situation. Only thing that is in my favour at this point is that it was not actually running when it got into the "lock up".

 

[NC-smokinlmm]

It's an LLY. Bet dollars to dimes it's a blown HG and it hydro locked...

 

[PureHybrid]

Try and hold pressure against it when it stops. Coolant will start to seep past the rings and the engine will slowly creep over (if that's the issue).

I've seen valves stick while cranking over before, in engines that sit for LONG periods of time. But that doesn't explain why it stalled and then still cranked.

Might be faster to pull injectors rather than fight corroded glow plugs.

 

[torqued2dmax]

Did you say water to air intercooler in your pre start list ? Just might be something there !

 

[outtatimexx]

RE; stuck engine

x2 on PureHybrid's advice. Take it slow, one step at a time, sound like a hydro-lock to me!

 

[torqued2dmax]

Dont wait to long rust in cylinders is not good!

 

[valleyduramax]

Ya, a water to air intercooler setup but no leaks from what i can see in regards to that. starting tear down tomorrow after work. soak everything in penetrating oil tonight and hope things go smooth. Might end up pulling motor completely if head gaskets and stud it. One step at a time though for sure.

 

[torqued2dmax]

Good luck tomorrow ! And do check that intercooler , I hope gaskets and studs are it .

 

[Digmax]

Cp3 might have grenaded and is only able to turn part of a round.... would explain the stall and lock up. Sounds strange for sure.

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[valleyduramax]

Ya I should mention that it was 5 gallons of fresh fuel with 2 liters of ashless 2 stroke oil before starting. Hope to know what issue is by tomorrow evening for sure

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[torqued2dmax]

Wow thats a lot of 2 stroke DHD Tony told me to use 4 oz per gal when racing , thats 20 oz in 5 gal , you put in about 4 times that much , I hope it was mixed real well because I dont know how thick of liquid a cp3 can pump 26000 lbs . Tell us what you find !

 

[Chevy1925]

The 2 stroke oil isn’t an issue. It will just smoke real bad if too much is in the system. I use to run a quart of it and a quart of diesel Kleen every so often on the last 10 or so gallons of fuel to “clean” my injectors before gm came up with the injector cleaner. Never caused an issue and lb7 injectors never lasted any long with that method lol

 

[valleyduramax]

Ya not worried about the amount of oil mixed into the fuel. Always run at least a liter per tank anyway. So I got the passenger side injectors removed and the positive is that there is no hydro lock on that side and injectors are pretty clean surprisingly. But broke the 4 hold down bolts in removal. Gonna deal with that later. The drivers side injectors are gonna come out tonight after work.