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Well I tested and confirmed I have a head gasket leaking, wasn't planning to do them till next year.
A bit of background, my low coolant started coming on. I had just replaced the thermostats and figured I could still have an air pocket that burped out, so I filled it again and guess what... light hit again! So I tested and found a small leak, I adjusted and stopped this leak. Filled the system and off I go, the damn light came on again. Now as fear starts to set in as I know what this is adding up to, I beak out the tester again and fire the beast up and let er purrr away. It climbs to 5 psi, then to 10 psi, we get to 15 psi, once it hit 18 psi it was clear. I goosed the throttle a couple of times and watched the psi's drop a couple and start climbing back, I shut it down at 20 psi and began weeping!!

But I guess you have to expect that when you hit 28 psi of boost when pulling a 10 k camper, that was a hell of a hill.

Anyone have recommendations to do while the heads are off? I know ARP studs are mandatory but is there anything else?

Thanks in advance!!
 

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Might as well do upgraded injector pigtails if you don't already have them, common issue with the LLY. Probably take the heads to a shop and have them hot tanked, pressure checked and maybe valves/seals (depends on how many miles are on the truck and condition of the heads). Definitely ARP head studs, about all I can think of.
 

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The truck is sitting at 138,800 miles.
 

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I have a question for those more knowledgeable than me regarding the HG failures.

It is my understanding that the HGs fail because the studs stretch. Naturally when the HG fails head removal is required.

My question..........would it be possible to change the studs, one at a time, with the heads still on the block to replace them all with the heavier duty studs, thus preventing the HG failure?
 

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I have a question for those more knowledgeable than me regarding the HG failures.



It is my understanding that the HGs fail because the studs stretch. Naturally when the HG fails head removal is required.



My question..........would it be possible to change the studs, one at a time, with the heads still on the block to replace them all with the heavier duty studs, thus preventing the HG failure?
I would never chance that. They must be removed and installed in a particular sequence, otherwise your aluminum head will warp.


Sent from my google machine
 

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I would never chance that. They must be removed and installed in a particular sequence, otherwise your aluminum head will warp.


Sent from my google machine
OK, so if it was done on a cold engine, in the correct sequence to break them all loose, but replaced one at a time so the head and gasket do not shift and then Torqued in the correct sequence?

Just trying to learn from those with more knowledge. Im NOT trying to sharpshoot here, just add to my personal knowledge base
 

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I'm not going to say it will or wont work on a LLY but I've done it exactly as you say (in torque sequence) on LS motors (also a torque to yield bolt) more than once and never had a failure. Done in the torque sequence, one by one, DO NOT loosen all of them at once, just ONE AT A TIME and the chance of warping the head is almost nonexistant.

BUT, the problem is not 'just' the bolts. The gasket sees a lot of movement when you have an iron block and aluminum head. If the stock gasket is weak and starting to fail, the stable compression of a high strength stud will still be just a bandaid.
 

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OK, so if it was done on a cold engine, in the correct sequence to break them all loose, but replaced one at a time so the head and gasket do not shift and then Torqued in the correct sequence?
This would most likely dump coolant into the cylinder.

I have no experience with replacing them one at a time, but I know my head gasket was burned up and physically damaged beyond what a stretched head bolt would have allowed. MarvDmax04.5 is correct, putting better studs in would bandade the bad head gasket material eventually giving up.
 

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Patriot Diesel, how quick did the pressure climb on yours while testing?

I just finished my rebuild on a used lly i bought. I had the heads machined but not pressure tested. Did ARP studs and hem gaskets. This thing build pretty very fast. Like 30 seconds of idle time and i have 10 psi. Im thinking i may have a cracked head.
 

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KTMTim it took around five minutes to hit 20psi, if your building the much pressure that fast I would agree with the cracked head. You could do a cylinder leak down test to help with diagnosis.
 

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If you end up doing a HG job, it isn't too bad, I did it here last year. I pulled the engine out and did it on the stand. It's just time consuming and the torque converter bolts are pita.

Things I replaced/used while I was in there.

t-stats
water pump (welded)
downpipe (I think MBRP)
up-pipes (PPE)
manifolds (PPE)
mouth piece
ARP studs
Glow plugs (AC Delco)
GM Grade C gaskets
cleaned injectors
lapped valves

I think that was all. I always meant to do a build thread to document it, but always forgot to start it. I got lucky too with my heads, they didn't need cut. Crack checked and checked the parallel of the head with an indicator at work.
 

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Patriot diesel, sorry I didn’t see your response. I did figure out it was cylinder 4. The. I pulled the engine and head. Sent it to the machine shop and they pressure tested it and confirmed that area was cracked near the injector.

The only way I could narrow it down to a cylinder was using a combination of coolant tester at 10 psi constantly and compression testing each cylinder while monitoring the coolant pressure. You could actually see the coolant pressure go up when the compression was built up.

Hope to have it running by the end of Monday.
 

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If you end up doing a HG job, it isn't too bad, I did it here last year. I pulled the engine out and did it on the stand. It's just time consuming and the torque converter bolts are pita.

Things I replaced/used while I was in there.

t-stats
water pump (welded)
downpipe (I think MBRP)
up-pipes (PPE)
manifolds (PPE)
mouth piece
ARP studs
Glow plugs (AC Delco)
GM Grade C gaskets
cleaned injectors
lapped valves

I think that was all. I always meant to do a build thread to document it, but always forgot to start it. I got lucky too with my heads, they didn't need cut. Crack checked and checked the parallel of the head with an indicator at work.

MKCoconuts

I was lined up to have a shop do it for $4,500 using ARB studs and GM head gaskets, it is a good reputable diesel shop but I think he decided he didn't like the price he gave me because her won't talk to me anymore on when to bring it in.
I would love to do my own work but I am a paraplegic and this task is out of my abilities but I may have to coach my son and cousin and get it done that way! Thank you for the advise on what all to change while it's tore down. Earlier this year I replaced the exhaust manifolds, up-pipes with RDP, 3" down-pipe, Y-bridge with WC-Fab, and the thermostats. The head gaskets were the next in line but I planned to do them next year. but they didn't wait!
 

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I did mine last May, for the torque converter bolts, use a 2ft extension on an air impact from the front of the truck. Makes quick work of them.

I also had the entire cooling stack and front clip removed.

Sent from my google machine
 

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I did mine last May, for the torque converter bolts, use a 2ft extension on an air impact from the front of the truck. Makes quick work of them.

I also had the entire cooling stack and front clip removed.

Sent from my google machine
That only works IF you have a air compressor and access to a good air impact, which I do have the a IR 2235 that I keep at my fathers, but I do not have a air compressor in my garage...yet. I tried using my fathers DeWalt 1/2 in drive electric impact but with the extensions it lost its leverage. I ended up using my 3/8 ratchet and a small pipe to break them loose. Ended up grenading the ratchet on the last one, but it broke the bolt loose, so it served its purpose. It's also not designed to have cheater pipe on it. I can't remember why I had to use the 3/8 ratchet instead of my 1/2 but I think I was constrained on room (out of extensions).

I too, had the front clip and cooling stack removed. I do want to note that I did not remove the hood nor did I put it in its service position.
 
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