i was told by a family mechanic that duramax heads are trashed once the head gasket is blown, and they you can not reuse them. He also mentioned that you can not machine the heads and that its better off to buy new heads or a new motor. Now my turn: The motor never over heated on me, but i have no idea if it did on the previous owner, but im still sending my heads to the machine shop to have them checked. what are my best options here and what else should i do other then studding the heads to help prevent any further issues. My motor is a lb7 by the way.
Head questions
- Thread starter Bagged93gmc
- Start date
I would run away from that mechanic . the heads can be refurbished if needed , not to say that all are repairable
yep ^^^^ i have them decked all the time. GM does say not to in their material though. I've yet to have a problem doing so though.
Just did mine, just take them into to see if they need machined, mine didn't they were actaully really clean, but most need a lil takin off, studs is pretty much the only thing you can do to help prevent it. Now is a good time to do some internal stuff if you have the money:thumb:
Actually the real story is that
1. yes they can be machined.
2. GM had a poor design for the gasket for the LB7, it has since been corrected.
3. if you get the deck and heads as close to a mirror finish as you can and use the revised torque procedure they will hold on for a very long time and even at higher than stock boost.
4. studs are better than bolts, but not required if you stay with a stock turbo.
Most "mechanics" don't know squat about the right way to rebuild a duramax. Research is required to learn the correct ways.
1. yes they can be machined.
2. GM had a poor design for the gasket for the LB7, it has since been corrected.
3. if you get the deck and heads as close to a mirror finish as you can and use the revised torque procedure they will hold on for a very long time and even at higher than stock boost.
4. studs are better than bolts, but not required if you stay with a stock turbo.
Most "mechanics" don't know squat about the right way to rebuild a duramax. Research is required to learn the correct ways.
Not all LB7s had the same gaskets
Thats the way I understand it also. GM made a change in even the later built 2001 Duramax. In other words if you have a late build date in 2001 you have the updated headgaskets.Also in 02 and beyond I wouldn't be concerned at all.
Not actually sure but that is what I was told.
Some other cause can also be from mixing coolants and running high timing. Sometimes you will get lucky and it will be a injector cup not a headgasket but thats only if your real lucky! Be intresting to see how many people have had to replace their headgaskets on their LB7s.
Something to note in this thread is that to mill the head and have it be done 100% correct the valve should be recessed the same amount that was removed from the surface area , but there is some room for margin depending on what is removed and the protrusion of the piston.
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mine was built in august of 01 (technically an 02) and it had the bad gaskets. had to have them replaced at 90k. I could be the only one though cause my truck is quarky as all hell
I was told by the GM stealership the same thing.They said that the head gasket that has the steel core ring in the gasket makes indentions in the head surf,that the head can not be resurfaced because they valves are already flush with the head surface and resurfacing them would get into the valve seats .
This is what I was told by the Rodger Dabbs GM dealer ship survice rep and mechanic.
The problem I had was loosing coolant,Ran fine no loss of power,Dabbs said head gasket,I looked and it wasn't leaking on the outside.When he pulled it in the shop said it was blowing white smoke out the tail pipe ,I never saw that,but could be because the water was not going any were else.(Heres were I got screwed they did not do a coolant die test to see where it was leaking)I learned all this after $6800 bill. I kinda knew the mechanic Tim for racing and stuff and really he's the only factory trained diesel tech here in town,So I went up there to see the motor tore down to see the socalled blown head gasket, he had already wire brushed the head surface's and showing me the grooves from the head gasket in them., Now Ive blown a many headgaskets on race cars, NOS etc.I didn't see any signs of blown head gasket or coolant passages on the deck surf and that would of left sings of the coolant cleans the surface when leaking,All said and done I'm betting that the injector sleeves that I'm told can leak coolant was prob what was wrong.Too late then.
All this was at 91k miles 8-2009 and 2012 now at 105k the injectors are leaking blowing white smoke at idle. and there talking $5,000 for that. Its starting to look like a New truck would be cheaper now?
Hope this helps, sorry long story.
heres the thread I posted of all the picks on the internals
http://www.dieselplace.com/forum/showthread.php?t=325924&highlight=
Goodluck!!!
Rob Stringer
This is what I was told by the Rodger Dabbs GM dealer ship survice rep and mechanic.
The problem I had was loosing coolant,Ran fine no loss of power,Dabbs said head gasket,I looked and it wasn't leaking on the outside.When he pulled it in the shop said it was blowing white smoke out the tail pipe ,I never saw that,but could be because the water was not going any were else.(Heres were I got screwed they did not do a coolant die test to see where it was leaking)I learned all this after $6800 bill. I kinda knew the mechanic Tim for racing and stuff and really he's the only factory trained diesel tech here in town,So I went up there to see the motor tore down to see the socalled blown head gasket, he had already wire brushed the head surface's and showing me the grooves from the head gasket in them., Now Ive blown a many headgaskets on race cars, NOS etc.I didn't see any signs of blown head gasket or coolant passages on the deck surf and that would of left sings of the coolant cleans the surface when leaking,All said and done I'm betting that the injector sleeves that I'm told can leak coolant was prob what was wrong.Too late then.
All this was at 91k miles 8-2009 and 2012 now at 105k the injectors are leaking blowing white smoke at idle. and there talking $5,000 for that. Its starting to look like a New truck would be cheaper now?
Hope this helps, sorry long story.
heres the thread I posted of all the picks on the internals
http://www.dieselplace.com/forum/showthread.php?t=325924&highlight=
Goodluck!!!
Rob Stringer
