12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

headgasket failure

Old Apr 13, 2009 | 07:49 PM
  #1  
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Default headgasket failure

ok guys on my way to work thismorning truck has been running good since rebuild other than the coolant issue. noticed there is antifreeze pissing out of the rear of my headgasket, whould water temp being to hot casue this to happen. durring rebuild it got a shaved head and oversized gasket. i was running at 60mph with only 10psi of boost so i dont think that caused this
 
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Old Apr 13, 2009 | 08:27 PM
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if ur coolant temp gets too hot it can crack the head.
 
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Old Apr 13, 2009 | 08:29 PM
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thats to hot, it aint that hot yet belive me, i had it so hot it shut the truck off, melted the 5th piston, scored 3 cylanders, warped/cracked the last head, callapst 3 wrist pin bearings. thats hot hot the coolant got last month
 
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Old Apr 13, 2009 | 09:11 PM
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did you have the head maged for cracks? it could have been cracked and just now cracked enoughf to leak.
 
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Old Apr 13, 2009 | 09:18 PM
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did you do a series of heat cycles and re-torques on the head bolts? or just a single torque and that was it?
 
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Old Apr 13, 2009 | 09:32 PM
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Originally Posted by 94cummins12v
thats to hot, it aint that hot yet belive me, i had it so hot it shut the truck off, melted the 5th piston, scored 3 cylanders, warped/cracked the last head, callapst 3 wrist pin bearings. thats hot hot the coolant got last month
exactly, it dont have to be that hot to crack the head... ^^^ thats rediculous tho
 
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Old Apr 13, 2009 | 10:58 PM
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the head was magnafluxed and pressure checked before installed. i have studs not bolts and i torgue them 3 times. hand tighten once, 60ftlb, then 90ftlbs then 135ftlbs all threw the sequence

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we will pull the head tomarrow night and see what the deal is, my thought is that it is leaking belween the two layers of the headgasket. looked funny to me but thats my opinion
 

Last edited by 94cummins12v; Apr 13, 2009 at 10:58 PM. Reason: Automerged Doublepost
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Old Apr 13, 2009 | 11:08 PM
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IIRC once you get to the final TQ you need to heat cycle the motor and then re-tq it to the final tq. the hear will expand and then contract the metal stretching things. you just need to take up the slack. but it is already leaking. the gasket needs replacing now....
 
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Old Apr 14, 2009 | 11:05 PM
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oh ya i got another gasket on the way, them overside gaskets aint cheep, anyway the last time i installed the studs back in november i didnt heat them then torque just the first torgue before statring it and didnt have a problem till the engine melted. i will do that this time. how many times for the t-stat to pop before i need to torque again. or should i torque, drive till it pops a few times then torque it again?

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ok guys got the head off and all i got to say is wow, that gasket was toast, front piston had a compression leak out into no were, 4 had a compression leak into the cooling, all cooling holes in the gasket were bubbled up, and the rear of the gasket was completely gone, my gues is it was put on bad, damn 2 a.m. nights putting another on tomarrow
 

Last edited by 94cummins12v; Apr 14, 2009 at 11:05 PM. Reason: Automerged Doublepost
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Old Apr 15, 2009 | 09:04 AM
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i'm not going to say that there's nothing to that theory,but when metal heats up it expands,wich means the head would actually be tighter when hot.when it cools off it will shrink,but not smaller than orig.there might be a little to it,but i've rebuilt a few,and after i tourqed them they were there,i tried to re-tourqe them and they wouldn't,still doesn't hurt,i'm just saying,he may want to look a little further than just slapping a new gasket and trying a different method of tightening.
 
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