Head Gasket Job

[Belldiver]

Hi folks!

First couple posts here and I'm a bit new to diesel engines. I'm pulling the block on my father in-laws '04 GMC 6.6 Duramax to replace the head gaskets and do any other basic stock upgrades that should be done at the same time. The truck has all the symptoms of a blown head gasket leaking compression gasses into the coolant system and I've also checked and verified with one of the liquid coolant/gas testers. Blue --->Green.

I keep reading about the ARP stud upgrade from stock head bolts and have a question about torque plate honing. I understand this is a step you might want to take with a new build/bare block, but is it necessary/required for just a basic HG job on a motor with 108K miles on it? This motor is not tuned, boosted, nothing...bone stock. It gets mild use most of the time, and twice yearly hauls a 32' 5th wheel trailer about 2500 miles and the driver does NOT have a heavy foot.

The lower end of this engine is still in great shape and I don't plan on pulling the pan unless I find some reason after the block is out.

I do plan on replacing the water pump at the same time just for good measure. Is there anything else I should consider while the block is out?

Thanks for any advice. ARP Studs, Water Pump. Injectors? Glow Plugs? Oil Cooler? Oil Pump?

Jim

 

[ripmf666]

Have the heads checked and valve job done. No on the tq plate honing at that point you would be into a full overhaul. Pistons need to come out and you would be replacing torque to yield bolts and bearings.

 

[jlawles2]

Welcome to the site.

Since its your first time working on a Duramax, I suggest the Haynes techbook specific to the Duramax. Haynes number 10331.

I got mine from Summit, but several vendors here may have it.

Good luck on the job. Just did a bent rod in my Dmax and the techbook helps some.
I suggest taking lots of pictures of the wiring and hose locations.

 

[Belldiver]

I ordered that exact manual last week. Should be showing up any day now.

Definitely have plans on lots of pictures, plastic bags, coffee cans, and Sharpie markers. I've been through this before plenty of times with gas engines, this is just my first diesel.

I do need some advice on what to do with the injectors though. Any maintenance or cleaning I should do at 108K miles?

Thanks,

Jim

 

[JoshH]

LB7 or LLY?

 

[Belldiver]

It's a 2004 GMC 2500 HD, 6.6 liter. I assumed it was a LB7? Could I be wrong here? I don't honestly know right now and I am currently offshore on a ship in the Gulf of Mexico. I could probably get somebody at home to take a picture or get me the VIN number.

Thanks,

Jim

 

[JoshH]

They changed mid year from the LB7 to the LLY. It could be either one. The 8th digit of the VIN will be a 1 for the LB7 and a 2 for the LLY.

 

[pullsanything]

Change the thermostats also.

 

[Belldiver]

I changed both thermostats when I started troubleshooting. No change in results.

 

[Belldiver]

They changed mid year from the LB7 to the LLY. It could be either one. The 8th digit of the VIN will be a 1 for the LB7 and a 2 for the LLY.

I'll have someone at home get me the VIN. Thanks for the info.

 

[pullsanything]

I changed both thermostats when I started troubleshooting. No change in results.

I just meant to change them while you had it down, not that it would fix your problem... anyhoo... :thumb:

 

[Belldiver]

Any thoughts on the injectors? Preventative maintenance?

 

[pullsanything]

Any thoughts on the injectors? Preventative maintenance?

This will depend on if LB7 or LLY. Still, it is important to keep the injectors and feed lines as clean as possible to prevent contamination. Other than that good filtering is about the best you can do as far as preventative measures.

 

[duramatt05]

I've done a couple llys and I just clean the carbon off the tips put new copper washers on. I would suggest if u havnt already, buy a headgasket replacement kit from merchant or creatures of the night. Comes with everything you will need to do the job.

 

[Belldiver]

I'll have someone at home get me the VIN. Thanks for the info.

OK, got the VIN #1GTHK23294F xxxxxx

Looks like this must be an LLY motor?

Hate sounding like a total noob, but what are the major differences?

Thanks,

Jim

 

[pullsanything]

The major diffs are LLY and newer have a variable geometry turbo and the injectors are accessible outside the valve covers where the LB7's are not.

 

[pullsanything]

Here is a great article that describes the history of the Dmax.
http://www.dieselpowermag.com/features/1303dp_history_of_the_duramax_diesel_engine/

 

[Belldiver]

Great article! Thanks!

 

[Belldiver]

Then do I need an injector puller tool for a LLY engine?

Any other specialty tools needed? I'm covered on all the basics...

 

[JoshH]

No injector pulled required. I can't think of any specialty tools you'll need to do head gaskets.