*LONG POST*
I just recently did Head Gaskets on my LLY at 92K and just wanted to give some info on it for people that are curious or to help them determine if it's something they can tackle since I've seen posts on all of the forums asking questions about it.
First off, this is not going to necessarily be a "How-to" but just a guide containing the answers to the questions that are commonly asked. What I discuss here is totally open, so feel free to add to it but please constructive criticism only.
I would rate this job at about a 7/10 difficulty level. IMHO, anyone who has moderate mechanical experience shouldn't have any issues. I've previously worked at a dealership and done a fair amount of side work on various vehicles so I would rate my experience as "moderate".
So how long did it take me? I will say this job easily took me the better part of around 50 hours by the time I made multiple trips to Sears, part stores, machine shop, and pretty thorough cleaning. Like any other big job, since I've done it once I could probably do it again a lot faster.
What Tools did I need? I will go under the assumption that anyone attempting this will already have the general stuff (pretty broad socket sets, screw drivers, various pliers, etc). I have a large array of tools from working at a dealership.
The other stuff:
17mm 12 point - Factory head bolts
16mm 12 point - ARP stud nut size
10mm 12 point - The smaller ARP bolt
12mm 12 point - up pipe to manifold flange bolts (mine were REALLY tight)
36mm 12 point - Crank bolt, ONLY if you do water pump also
Flywheel hold tool - Only for crank bolt and water pump
Case of brake clean - I went through a TON of brake clean
Fuel Line disconnect tools
Crows feet for fuel lines
1/4" and 3/8" drive allen sockets
PB Blaster
Razor Blades
Scotch Pads
600 Grit sand paper
Air Tools - Aren't required but helped out a lot, having a blow gun, air ratchets, air hammer, impact, and drill helped me out.
Feeler gauges
Torque wrench that goes to 125 ftlbs
Straight edge
Extractor and Easy-out sets - I'll get into this later
Shopping List: Here's my parts list with ball park costs
Head Gasket Kit w/ studs - Comes with all gaskets and seals necessary, a lot of vendors sell them and IMHO, you'd be silly not to do studs while you're in there. I got grade "C" gaskets. ($1000ish)
Permatex RTV - Used for intake manifolds because they don't have regular gaskets
Water Pump with upper and lower hoses - I did this as preventative. Got a welded pump with cover. ($250ish with hoses)
Injector return lines - I would just go ahead and get both sides. All but 1 of them snapped off no matter how gentle I was. ($150ish...?)
8 Glow plugs - I had one snap off in the head and the others were nasty and rusty. I'd get either Bosch or AC Delco ($120ish I think it was for all 8)
Various 3/8", 5/16", 1/2" fuel line, and misc hardware - I replaced all the little rubber hoses in the valley since they were dry rotted. I needed a little extra because my set up is a little different with the EGR delete. I also used a few 3/8 elbows where there were bends, works just fine. 1/2" Line is for the 2 lines that connect to fuel filter assembly. I also replaced fasteners such as the valve cover bolts (stripped). Big hardware supplier called Fastenal had just about all the hardware I needed.
Machine Shop - There may be some debate here. I had my heads hot tanked, pressure tested, snapped off glow plug removed, and they shaved off about .005". Anything more than about .006" you need to start thinking about getting valves recessed and taking the same amount off the intake side so the Y bridge can fit properly. I didn't think valve job and seal/guide replacement was necessary due to my mileage and my heads looked like they were in pretty good shape. Machine shop also agreed that I didn't need seals/guides etc. To each their own on this topic, feel free to add. ($330ish)
Oil, Oil filter, and 3 jugs of coolant - Obvious reasons, but I would suggest changing oil due to all the contaminants from cleaning.
Disassembly:I'm not going to get in great detail here, but just a brief overview. I may have left a few steps out, just trying to highlight the important parts and give you "the jist". Not everything here may be necessary, but it's how I did it.
Preliminary
*Just about everything on top of the engine needs to come off
*Having a helper especially for head removal and installation is almost mandatory
*Cab does not need to be removed
*Soak all manifold bolts and glow plugs with PB blaster before hand
*I removed my big ranch hand front bumper, grill and lights
*Removed my hood
*I used zip lock bags and masking tap to keep track of fasteners. Just taped them to the component and labeled as necessary.
*I removed everything as layers from the outside in
*Steering column removal was not totally necessary but I think removing it made more room for the driver side manifold and it's easy to remove.
*Snap some pictures as you go
*Watch out for the dowels for the valve cover, rocker bar, and heads
1. Start off draining the coolant with the petcock on radiator, and remove intake, both batteries, coolant resovoir, flip over A/C compressor, and shrouds. Flip TCM up over where the driver side battery was, no need to disconnect. Hydroboost and fuse box can stay.
2. Work your way in and around by removing fan clutch (I used the large chisel and hammer trick), fuel filter assy and FICM. unbolt P/S pump and let it hang. I removed the left and right side accessory brackets with all the pulleys and alternator attached. I also removed the coolant cross over pipe and thermostat housing as a whole piece
3. Once I got most of the outer components out of the way, I disconnected all the harness connectors and let it all hang in front of the motor. Removed my 1 piece Y Bridge and tube. I then disconnected the injector return lines, fuel rails, lines in the valley, and took those out as 1 piece.
4. Then came injectors, and LOWER valve covers. Upper valve covers don't need to be seperated from the lower. Injectors came out from using a screw driver to pry up on the hold down. Normally the A/C accumulator does not need to be removed, but I didn't have a choice because I had a few valve cover bolts (5mm allen head I think) round off on me. Only way to get them out was drill the head off. So be careful with these and make sure you get a nice bite on them. Turbo can also stay in
5. Around this point is when I decided to removed the exhaust manifolds, I thought it would be easier to maneuver the heads around with them off. You may need to disconnect the down pipe also to get a socket on the inner flange bolt (pass. side).
6. I loosened all the valve adjusting screws to relieve some of the tension, then removed the rocker bar (alternating method) and push rods.
7. BAM! you're ready for head removal. I used a combination of my impact and breaker bar, they're tight. Note: The rear lowest head bolt on the driver side may not be removed while the head is in the car, I left it in the head and removed with the head.
Cleaning: This took a while for me. I used a bucket with highly concentrated simple green for the intake manifolds and the valve covers. The intake manifolds were FILTHY.
Throw a few clean rags down the lifter valleys and in the cylinder bores.
For the Block I used 600 grit sand paper wrapped around a small block of wood and wet sanded with WD-40. And then I used razor blades and scotch pads as needed. The sand paper thing is GM's procedure, and they DO NOT call to take it down to a mirror finish. I went until I was satisfied without any high spots, etc. Air tools are debatable here, use at your own discretion.
Shortly before the heads went on I blew out the head bolt holes with compressed air and made sure they felt smooth using one of the old but clean head bolts.
Assembly: I'm only going to highlight some things, it's mainly just reverse of the disassembly.
***Tape the lower driver side stud in the head BEFORE you put the head back on***
*Install intake manifolds onto heads before heads go back in the truck
*It helped a lot having a buddy help guide the heads back on
*Follow ARP instructions for torquing the heads down. I had a buddy keep track of the pattern while I torqued them down in 3 stages of 40, 90, and a final 125 ft lbs.
*Injector seals and coppers must be replaced, they come in the head gasket kits
Note: There is a video on youtube of a guy doing this procedure doing some crazy stuff like starting on the outside and working in, etc. IMHO, this guy is wrong and I don't know where he got his procedure because ARP's instructions are nothing like that.
*Do a search on how to set valve lash, there's a lot of tutorials out there. I set mine at about .011" and it took forever for them to keep my adjustments, so just be patient.
*I put anti seize on just about everything
*Rocker bar bolt torque is 30 ft lbs
First start up: I filled my cooling system up with water, and primed the fuel system. Truck started right up. I let it idle for a good 30-45 minutes to get it nice and hot and check for leaks. After that, I changed the oil and drained the cooling system to get all the dirt and contaminants out. Refill
Here a couple pics that I took on the attachments, and I don't know who this is but these pics came in handy also. So whoever you are, thank you for taking all these pics as well: Duramax LLY headgasket job - JohnVH's Photos
Think I covered most of the important things, feel free to add.
I just recently did Head Gaskets on my LLY at 92K and just wanted to give some info on it for people that are curious or to help them determine if it's something they can tackle since I've seen posts on all of the forums asking questions about it.
First off, this is not going to necessarily be a "How-to" but just a guide containing the answers to the questions that are commonly asked. What I discuss here is totally open, so feel free to add to it but please constructive criticism only.
I would rate this job at about a 7/10 difficulty level. IMHO, anyone who has moderate mechanical experience shouldn't have any issues. I've previously worked at a dealership and done a fair amount of side work on various vehicles so I would rate my experience as "moderate".
So how long did it take me? I will say this job easily took me the better part of around 50 hours by the time I made multiple trips to Sears, part stores, machine shop, and pretty thorough cleaning. Like any other big job, since I've done it once I could probably do it again a lot faster.
What Tools did I need? I will go under the assumption that anyone attempting this will already have the general stuff (pretty broad socket sets, screw drivers, various pliers, etc). I have a large array of tools from working at a dealership.
The other stuff:
17mm 12 point - Factory head bolts
16mm 12 point - ARP stud nut size
10mm 12 point - The smaller ARP bolt
12mm 12 point - up pipe to manifold flange bolts (mine were REALLY tight)
36mm 12 point - Crank bolt, ONLY if you do water pump also
Flywheel hold tool - Only for crank bolt and water pump
Case of brake clean - I went through a TON of brake clean
Fuel Line disconnect tools
Crows feet for fuel lines
1/4" and 3/8" drive allen sockets
PB Blaster
Razor Blades
Scotch Pads
600 Grit sand paper
Air Tools - Aren't required but helped out a lot, having a blow gun, air ratchets, air hammer, impact, and drill helped me out.
Feeler gauges
Torque wrench that goes to 125 ftlbs
Straight edge
Extractor and Easy-out sets - I'll get into this later
Shopping List: Here's my parts list with ball park costs
Head Gasket Kit w/ studs - Comes with all gaskets and seals necessary, a lot of vendors sell them and IMHO, you'd be silly not to do studs while you're in there. I got grade "C" gaskets. ($1000ish)
Permatex RTV - Used for intake manifolds because they don't have regular gaskets
Water Pump with upper and lower hoses - I did this as preventative. Got a welded pump with cover. ($250ish with hoses)
Injector return lines - I would just go ahead and get both sides. All but 1 of them snapped off no matter how gentle I was. ($150ish...?)
8 Glow plugs - I had one snap off in the head and the others were nasty and rusty. I'd get either Bosch or AC Delco ($120ish I think it was for all 8)
Various 3/8", 5/16", 1/2" fuel line, and misc hardware - I replaced all the little rubber hoses in the valley since they were dry rotted. I needed a little extra because my set up is a little different with the EGR delete. I also used a few 3/8 elbows where there were bends, works just fine. 1/2" Line is for the 2 lines that connect to fuel filter assembly. I also replaced fasteners such as the valve cover bolts (stripped). Big hardware supplier called Fastenal had just about all the hardware I needed.
Machine Shop - There may be some debate here. I had my heads hot tanked, pressure tested, snapped off glow plug removed, and they shaved off about .005". Anything more than about .006" you need to start thinking about getting valves recessed and taking the same amount off the intake side so the Y bridge can fit properly. I didn't think valve job and seal/guide replacement was necessary due to my mileage and my heads looked like they were in pretty good shape. Machine shop also agreed that I didn't need seals/guides etc. To each their own on this topic, feel free to add. ($330ish)
Oil, Oil filter, and 3 jugs of coolant - Obvious reasons, but I would suggest changing oil due to all the contaminants from cleaning.
Disassembly:I'm not going to get in great detail here, but just a brief overview. I may have left a few steps out, just trying to highlight the important parts and give you "the jist". Not everything here may be necessary, but it's how I did it.
Preliminary
*Just about everything on top of the engine needs to come off
*Having a helper especially for head removal and installation is almost mandatory
*Cab does not need to be removed
*Soak all manifold bolts and glow plugs with PB blaster before hand
*I removed my big ranch hand front bumper, grill and lights
*Removed my hood
*I used zip lock bags and masking tap to keep track of fasteners. Just taped them to the component and labeled as necessary.
*I removed everything as layers from the outside in
*Steering column removal was not totally necessary but I think removing it made more room for the driver side manifold and it's easy to remove.
*Snap some pictures as you go
*Watch out for the dowels for the valve cover, rocker bar, and heads
1. Start off draining the coolant with the petcock on radiator, and remove intake, both batteries, coolant resovoir, flip over A/C compressor, and shrouds. Flip TCM up over where the driver side battery was, no need to disconnect. Hydroboost and fuse box can stay.
2. Work your way in and around by removing fan clutch (I used the large chisel and hammer trick), fuel filter assy and FICM. unbolt P/S pump and let it hang. I removed the left and right side accessory brackets with all the pulleys and alternator attached. I also removed the coolant cross over pipe and thermostat housing as a whole piece
3. Once I got most of the outer components out of the way, I disconnected all the harness connectors and let it all hang in front of the motor. Removed my 1 piece Y Bridge and tube. I then disconnected the injector return lines, fuel rails, lines in the valley, and took those out as 1 piece.
4. Then came injectors, and LOWER valve covers. Upper valve covers don't need to be seperated from the lower. Injectors came out from using a screw driver to pry up on the hold down. Normally the A/C accumulator does not need to be removed, but I didn't have a choice because I had a few valve cover bolts (5mm allen head I think) round off on me. Only way to get them out was drill the head off. So be careful with these and make sure you get a nice bite on them. Turbo can also stay in
5. Around this point is when I decided to removed the exhaust manifolds, I thought it would be easier to maneuver the heads around with them off. You may need to disconnect the down pipe also to get a socket on the inner flange bolt (pass. side).
6. I loosened all the valve adjusting screws to relieve some of the tension, then removed the rocker bar (alternating method) and push rods.
7. BAM! you're ready for head removal. I used a combination of my impact and breaker bar, they're tight. Note: The rear lowest head bolt on the driver side may not be removed while the head is in the car, I left it in the head and removed with the head.
Cleaning: This took a while for me. I used a bucket with highly concentrated simple green for the intake manifolds and the valve covers. The intake manifolds were FILTHY.
Throw a few clean rags down the lifter valleys and in the cylinder bores.
For the Block I used 600 grit sand paper wrapped around a small block of wood and wet sanded with WD-40. And then I used razor blades and scotch pads as needed. The sand paper thing is GM's procedure, and they DO NOT call to take it down to a mirror finish. I went until I was satisfied without any high spots, etc. Air tools are debatable here, use at your own discretion.
Shortly before the heads went on I blew out the head bolt holes with compressed air and made sure they felt smooth using one of the old but clean head bolts.
Assembly: I'm only going to highlight some things, it's mainly just reverse of the disassembly.
***Tape the lower driver side stud in the head BEFORE you put the head back on***
*Install intake manifolds onto heads before heads go back in the truck
*It helped a lot having a buddy help guide the heads back on
*Follow ARP instructions for torquing the heads down. I had a buddy keep track of the pattern while I torqued them down in 3 stages of 40, 90, and a final 125 ft lbs.
*Injector seals and coppers must be replaced, they come in the head gasket kits
Note: There is a video on youtube of a guy doing this procedure doing some crazy stuff like starting on the outside and working in, etc. IMHO, this guy is wrong and I don't know where he got his procedure because ARP's instructions are nothing like that.
*Do a search on how to set valve lash, there's a lot of tutorials out there. I set mine at about .011" and it took forever for them to keep my adjustments, so just be patient.
*I put anti seize on just about everything
*Rocker bar bolt torque is 30 ft lbs
First start up: I filled my cooling system up with water, and primed the fuel system. Truck started right up. I let it idle for a good 30-45 minutes to get it nice and hot and check for leaks. After that, I changed the oil and drained the cooling system to get all the dirt and contaminants out. Refill
Here a couple pics that I took on the attachments, and I don't know who this is but these pics came in handy also. So whoever you are, thank you for taking all these pics as well: Duramax LLY headgasket job - JohnVH's Photos
Think I covered most of the important things, feel free to add.
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