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mark7.3idi

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I went out to start my truck this morning and it was dead so i got home this afternoon and jumped it. It ran good i went up town about 15 mile drive. i come home and my temp Gage gos to hot and i get home and shut it down and start it up after it stops boiling and it blue pear white smoke so i shut it down and called sootman73 and he came over to look at it and i went to start it and it hydro locked so now i am going to have to find a new motor or try to fix this one but the drive home it ran like it had never run before.LOL:puke:
 

Diesel JD

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I'd have to guess cavitation strikes again! Its entirely possible nothing broke. Have to tear it down and see if it was a head gasket or the big C and then if the rods are bent. I bet they are ok since it only locked at cranking speed not at WOT like it could have. You'll also have to fix the bores with sleeving, if it turns out that cavitation was the cause.
 

dyoung14

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I'd have to guess cavitation strikes again! Its entirely possible nothing broke. Have to tear it down and see if it was a head gasket or the big C and then if the rods are bent. I bet they are ok since it only locked at cranking speed not at WOT like it could have. You'll also have to fix the bores with sleeving, if it turns out that cavitation was the cause.

if i had one go to cavitation, i wouldnt do nothing except find me a 6.9 block
 

Chevyboy_0

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That sucks, I have a question, could someone explain hydrolock? I think I have an idea of what it is but I'm not sure.

Sorry bout the Hijack
 

icanfixall

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The term hydrolock has many explanations but usually refers to the cylinders being eaten out from the coolant side. This hole lets coolant into the cylinder thats affected. When fluid gets into the cylinder it wont compress like air does. So the motor stops turning. Now if this happens when the motor has started up you usually push a rod out of the block or at least a rod thru a piston. Coolant can enter the cylinders from a cracked head. A bad head gasket or cylinder cavation. The pistons raise up out of the blocks 31 thousands and the heads are flat. The only reason the pistons don't hit the heads is the head gasket thickness. The running clearance between piston and head is around 42 thousands....
 

CDX825

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hydro lock is when water or coolant fills the cylinder and stops the motor from turning.
 

THECACKLER

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ICANFIXALL - Thanx for the numbers. I was not awarer the t the IDI's had a negative deck height. Am I correct in assuming the Compressed Gasket Thickness is 0.011" or is the 0.042" accounting for Conn Rod Stretch & Oil Film Displacement.
 

icanfixall

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No... Not actually.... The pistons come up out of the block 31 tous... The headgaskets are around 72 thous. So subtract 31 from 72 and you have a clearance of 41 thous... Thats not much room for fluids and a broken glow plug tip will inbed in the piston tops. Sometimes they destroy the pistons and send the rods out the cylinders wndowing the block.
 

oldmisterbill

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JD -"I bet they are ok since it only locked at cranking speed not at WOT like it could have."

A little bit of information.I have seen in one of my own trucks hrdro lock break the adaptor plate that holds the starter & bend a connecting rod all in a split second. NEVER take a chance like trying to start an engine if you suspect water or coolant in a cylinder.!!!!
 

mark7.3idi

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Dose any one have a good used motor i cant seem to find one with less then 150000 miles and for less then $800 i am going to rebuild my after i get the other one just for a back up.
 

icanfixall

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There is always some 6.9 and 7.3 motors for sale on Ebay. No telling what condition they are in. You get what you pay for. A few years ago I bought a complete 7.3 motor on Ebay for $78.50.. Not a bad price. When I saw the motor sitting in the weeds of the sellers yard behind his house I knew it was a wet motor. Sure enough all the injectors were gone and when I got it home off came the heads. All wet cylinders but that was ok. I had planned to sleeve it. So I started to crank it thru just to clean out some of the crap and rust before I pulled the rods and pistons. The motor locked up. So I turn it the other direction and it locks up again..... Number 5 piston isn't moving up or down in the cylinder...-cuss-cuss The rat ******* had told me he pulled the motor because it had high miles on it. He drove it to and from Tiajuna and the upper desert homes he had.... ******** to that . The creep had thrown a rod.... It only did damage on the very bottom of the cylinder. That block sleeved fine and has been running now for 15,000 miles. I sure wish I could find that guy. I'd tell him I cleaned up the motor and just painted it... Wow... Look how good it runs and gees thanks a lot for the great price....:D
 

dyoung14

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i pick up a running 6.9 with a c6 out of a 4x4 truck all complete except its missing the tail shaft off the trans, and it has new head gaskets to:D
 

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