camaroextra

iTrader: (10)

I think I hydro locked the motor but I cant figure out how

02 ls1, stock internals. 100k miles (driven hard but not thrashed). synthetic.

I started it up one morning and it made a few terrible noises and then I heard the steady pounding that ended up being the piston skirt and the crank colliding. I pulled the motor before any more damage happened.

Upon close inspection I found:
-no cracks in the cylinder walls
-no cracks in the head
-head gaskets looked fine
-intake manifold looked fine
-bearings look fine
-spark plugs looked fine.

Everything looks like a normal engine with 100k on it.

I cant figure out how water or coolant got into my cylinder! Im rebuilding it and I dont want it to happen again.

Here is my only theory:

For all 6 years that I have owned it I have parked it facing downhill at maybe a 10 degree angle. I life in FL and it rains fairly often. There was water (not coolant) underneath the rubber seals flooding the knock sensors. I think that this position makes my car vulnerable to water somehow but Im not sure.

Any ideas or experience you want to share? Thanks my ninjas.

NemeSS

iTrader: (127)

Strong gasoline smell in the oil? Had a recent tune lately?

camaroextra

iTrader: (10)

neither. stock tune, stock internals. boltons only.

O2Form

Let me guess it rained between the time you shut it off and when this happened? How tight were the intake bolts when you disassebled it?

DaveX

I don't know but I have seen at least 2 other threads with similar issues. From what I remember they were both parked outside and had some miles on them. Looks like you got pretty lucky even though it's bad enough.

camaroextra

iTrader: (10)

no it didnt rain. It hadnt in a few days. I drove it home from work, didnt go out after that. Got up in the morning and wham

joecar

Which cylinder # was that...?

Jeremy@RPMTransmissions

iTrader: (12)

It doesn't take much fuel from a leaking injector to bend a rod.

Randy WS6

iTrader: (69)

^^^Im betting on this one ^^^, A leaky injector will do this over time, and being parked on a angle, the fuel in the rails will lead to the leaky injector. But the top ring gap would haft to be up hill on the cylinder and would fill the cylinder with fuel till it made it to the ring gap.Theoretically if your car was parked on a down hill and the ring gap was up hill it would hold a lot of fuel and the steeper the hill the more fuel the cylinder would hold.

BlackScreaminMachine

iTrader: (17)

Seen a leak injector do this. Remember, you cant compress a liquid, the amount a pressure needed will make other parts fail far before that.

trans_am7935

iTrader: (15)

wow that sucks, is this common at all?

camaroextra

iTrader: (10)

#1. and the car was tilted downhill. thats the furthest down cylinder.


This is a very intriguing theory. Is there any way I could test this? connect my fuel rail and just tilt it and see if anything leaks out overnight? or are there any other forces I need to recreate other than the angle

Paul 75 L82

iTrader: (1)

I think the guys got the right answer on this one. Has to be fuel.

Randy WS6

iTrader: (69)

You could pull the fuel rail with the injectors & fuel line connected and turn the key on run but not start, let the fuel pump run and see if there's any of the injectors are dripping

O2Form

I'll tell you what i've seen, I had a computer go bad and turn the injectors on with out the engine running. It filled ALL the cylinders with fuel before I knew what was going on. I cranked it like this multiple times and then started after replacing the computer. I jnew it was cranking funny but I didn't realize it filled all the cylinders with fuel. THERE WAS NO DAMAGE the oil was just overfull by about a gal! So i just can't believe fuel could hydro the engine, I think it moves past the rings to quickly. Now water won't move past the rings fast enough and will hydro the engine.

I havn't seen a newer fbody yet that the cowling aropund the windshield didn't drip water directly on the top of the intale manifold. I sealed mine all along the edge because every time it rained the top of the engine was wet AND a few times it started VERY FUNNY after it rained PLUS I also found ALL the intake bolts were loose. I'm still betting it showered while it sat and got in. At least you were smart enough to not run it long, should be a easy fix. Good Luck

mattster03

iTrader: (22)

bumping this back up to the top. i installed a new set of injectors and one of them was hung wide open, i had no idea and went to start the engine. when it reached the compression stroke of that cylinder with the bad injector it completely stopped the engine from spinng and broke one of the mounting tabs of the starter. after evacuating the cylinder of fuel (it was practically full) and restarting there appears to be no damage in that there is no knocking, weird noises, vibrations, etc. i am hoping the starter broke before it was able to put enough force into the connecting rod to bend it... but skeptical. what does everyone think... if the rod was even slightly bent would it be noticeable?

S10xGN

iTrader: (11)

Compression check will tell you everything you need to know...

OldCobraGuy

iTrader: (2)

^^^ Not necessarily. If it's bent bad enough to affect compression, it should make noise as well. I've seen them run with very little bend in them. But they eventually fail big time.

S10xGN

iTrader: (11)

OK, I just realized that the above post was a from a hijacker and not the OP. This poster was asking if a bent rod would be noticeable.

In the OP's original post, his piston prolly sets 1/8" down from the rest. A compression check would definitely read low on that cylinder. I don't see any mention of a "running" noise in either post...

Whistler

iTrader: (46)

The OPs engine had a knocking noise coming from the piston skirt contacting the crank counterweight. If the rod were bent less there would have been no noise.