Head gasket build

lb7resto

New member
Jul 19, 2023
23
9
3
NC
So I'm about to tear into this truck I just bought that is blowing coolant out of the reservoir. I am trying to get a plan together for what all I might change from stock while I'm in there. I am also trying to get a handle on its current state before I tear it all apart. I am new to diesel trucks though so I need some guidance.

Here is what I know:
- 2004 Silverado 2500 LT CCSB Auto 255k miles
- Truck has been sitting, parked by PO when it first had the issue about 2 years ago, dead batteries for about 6 months.
- Took a bunch of priming with that hand pump on the filter to get it to run (idk if that would be expected or is a sign of something. The 3cyl Yanmar in my tractor will start right up like you just turned it off after sitting for a year)
- It runs about like I would expect a gasser to run that has a bad misfire, very lopey but not consistently and shakes the truck a bit, and you can hear the loss of compression when it is turning over
- No water in the oil
- It has had a tuner of some kind at some point. PO mentioned that PO before him had the tuner display in the overhead console.
- Code P0088 is pending and comes right back

I have been on the google learning as much as I can and I had the thought that it would be prudent to check the health of the cp3 and the injectors and anything else I can while I can still start it up, before I tear it down. Well, I hooked up to it with Torque Pro and checked the balance rates, I think one of the cylinders was a little high, like 3.5, but what is strange to me about that is the values all go to zero as soon as I touch the skinny pedal at all (we dont call it gas or throttle right? whats it called on a diesel? lol). Another thing weird is I found a PID in Torque Pro for rail pressure and I'm wondering about that P0088 so I check that out and it dances around 24000psi at idle and goes up to and hard stops at something like 26k as soon as I touch the skinny pedal. So those are my first two questions for you all, is that normal about the balance rates and the rail pressure (reading over OBD2)? It has me wondering about ECM issues or a tune maybe still being on it or some fuel pressure mod, why else would I be getting P0088?

Next, is there anything else like that I should check out before tearing it down?

Finally (for now) can you all help a guy think about what I might want to replace preventatively while I'm in there, and any mods I might want to do for the truck to live a long life (and maybe add some safe power such that the transmission will also live a long life). I want reliability and longevity first and foremost. I am not DDing it, or racing anyone, or stunting around town on 37s. I need it to do truck things when I need to do truck things, and pull a heavy trailer sometimes.

Thanks for reading
 

2004LB7

Well-known member
Dec 15, 2010
6,596
1,909
113
Norcal
Throttle or accelerator is appropriate. some still call it the gas pedde but we look at them funny. 😛

the P0088 is a result of the high fuel pressure. it's also likely the cause of the loping and rough running engine. the balance rates won't be of much use until you can get the pressure down closer to the desired. it is likely from a stuck regulator on the CP3. but can also be from a bad wire or unplugged connector at the regulator. also, if you unplug the connector at the pressure sensor it will also show maximum pressure. so check that too. if you decide to replace the regulator, get a genuine bosch one, which run about $120-150 or so. if you get an ebay special or some other knockoff for less you will be chasing fuel pressure issues or it will fail early.

the pressurized coolant could be from a head gasket or the cups. hard to say but you could do just the cups first and before putting it all back together install the injectors and see if it still has pressure in the coolant.

when you pull the fuel lines off the injectors you will most likely contaminate the injector fuel input with a bunch of rust and debris that has accumulated around the nut and fell in as you take it off. you will need to "carefully" clean this out by turning the injector upside down and whacking the fuel line connector part of the injector on a piece of wood or similar surface. do this until the port is clean inside then rinse in a bucket of diesel or other solvent. don't try and spray carb cleaner or compressed air in it to clean it as it will just push debris further in. if you are lucky you won't need to buy and new injectors. if you do go for new injectors, go for the newer SAC00 ones. higher cost but much better life and reliability.

if it hasn't been done, look into doing the pump rub mod on the transfer case.

if you tune it, keep the power at 60 hp or less unless you want to get the transmission redone soon. with heavy towing i'd keep it at 30 hp. tuners are getting harder and harder to find and I personally don't like or recommend a canned tuner. but your call

keep us updated on progress and what you find
 

wydopenLb7

Active member
Mar 10, 2023
108
46
28
California
If the valve covers are coming off for head gaskets or to check the cups I would strongly recommend doing new injectors and new high pressure lines while you are in there. It’s not a job you will want to be doing twice.

Balance rates are only accurate at idle when the truck is at operating temperature. As soon as you hit the throttle they will zero out.

A lift pump with added filtration would also be a worthwhile mod to keep your new injectors healthy. Like I said it isn’t a job you will want to do again anytime soon.
 
  • Like
Reactions: Animals1234

lb7resto

New member
Jul 19, 2023
23
9
3
NC
Thanks for the input guys. I don't see a PID in Torque Pro for desired rail pressure. Any experience with that in Torque Pro or know what the OBD2 PID code is for desired, if there is one? I assume there is.

I was searching around about the SAC00 injectors and it seems like everyone loves the increased flow SACs but the SAC00 seems a little mixed. Any insight on that? Was there an issue when they released them that they fixed later? It would be nice to save the $ if I can get a warm and fuzzy about my injectors. If I can verify they are the newest bosch design and have them tested I will probably re-use.

When I get the valve covers off will it be pretty easy to tell if my issue is actually just the cups?

About the cp3, if it is making 25k psi at idle, it clearly isn't struggling to make pressure. Would you just replace the regulator (and add a lift pump) or would you go ahead and replace the pump preventatively?

It sounds like I wont be going for any more power to save the tranny. Maybe an economy tune and a stock tune

If it is head gaskets here's what I'm looking at so far:
Head gasket set (Grade C?)
ARP studs
CP3 regulator
Maybe injectors
High pressure lines
Lift pump

Any recommendations on where to source parts? Kennedy Diesel seems good...
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
3,986
1,125
113
Larsen, Wisconsin
Thanks for the input guys. I don't see a PID in Torque Pro for desired rail pressure. Any experience with that in Torque Pro or know what the OBD2 PID code is for desired, if there is one? I assume there is.

I was searching around about the SAC00 injectors and it seems like everyone loves the increased flow SACs but the SAC00 seems a little mixed. Any insight on that? Was there an issue when they released them that they fixed later? It would be nice to save the $ if I can get a warm and fuzzy about my injectors. If I can verify they are the newest bosch design and have them tested I will probably re-use.
Personally I try and use SAC45% in all of my LB7 customers vehicles as they have zero downside. The newest Bosch designs are good but still do not have the lifespan of a SAC nozzle.

When I get the valve covers off will it be pretty easy to tell if my issue is actually just the cups?

About the cp3, if it is making 25k psi at idle, it clearly isn't struggling to make pressure. Would you just replace the regulator (and add a lift pump) or would you go ahead and replace the pump preventatively?
Personally if I'm in a job that far and it's got higher mileage I always replace the CP3. Does that mean every CP3 is bad? No, just means I don't want to have to charge the customer labor twice and I explain that ahead of time. With the truck torn down for gaskets it takes ~10-15min to change a CP3 to the point where we don't charge labor to do it at that point.

It sounds like I wont be going for any more power to save the tranny. Maybe an economy tune and a stock tune
Solid plan.

If it is head gaskets here's what I'm looking at so far:
Head gasket set (Grade C?)
ARP studs
CP3 regulator
Maybe injectors
High pressure lines
Lift pump

Any recommendations on where to source parts? Kennedy Diesel seems good...
My shop does carry all of those items and we also are a site sponsor. Any of our site sponsors can help get you squared away as well.
 

lb7resto

New member
Jul 19, 2023
23
9
3
NC
PXL_20230914_222927398.jpg

Here's where I'm at. Trying to squeeze at least 15 min of time spent every day for a few weeks now. Slow and steady! This thing is definitely complicated. Feels like I'm really close to getting into the valve covers.
 

2004LB7

Well-known member
Dec 15, 2010
6,596
1,909
113
Norcal
Good job. First time can be intimidating but once your done it's rewarding. Also taking to long time to do it or only working on it a little at a time can cause issues with forgetting which bolt goes where so documentation and organizing the parts is important
 
  • Like
Reactions: wydopenLb7

pl_silverado

Active member
Jan 29, 2012
132
98
28
The only time I saw 25k psi at idle is when one of the wires between the ecm and fpr broke. If communication is lost the fpr defaults to max pressure from my understanding.

Just fyi, incase you get it all back together and see the same issue.
 

lb7resto

New member
Jul 19, 2023
23
9
3
NC
Got a little farther into it and wanted to get some opinions about what I am seeing.

First of all, it is clear someone has been in here before, which is fine, maybe it was the injectors or maybe it has even had the head gaskets done. But this drinkers side head looks like a reman, right? With the blue paint pen and the valve cover sticker and all that.
PXL_20230920_013026545.jpg
That's not an issue really, just interesting.

The other thing is this junk in my cooling system:
PXL_20230920_120738790.jpg
PXL_20230920_120806090.jpg

I've never seen something like this before. It feels like super fine mud, I'm thinking maybe it is some head gasket in a bottle stuff. Whatever it is, do any of you have any experience trying to dissolve and flush this stuff from a cooling system? I shudder to think what the passages in the block and heads look like, and I have to assume the radiator is trash now.

The only time I saw 25k psi at idle is when one of the wires between the ecm and fpr broke. If communication is lost the fpr defaults to max pressure from my understanding.

Just fyi, incase you get it all back together and see the same issue.
I appreciate that. I had heard that with no voltage it is at max pressure. I'll definitely check the wiring and connector.
 
  • Like
Reactions: Animals1234

2004LB7

Well-known member
Dec 15, 2010
6,596
1,909
113
Norcal
The deposits are possibly from the leaking head gasket. The orange coolant doesn't like contamination or air in the system. It will precipitate out silicates that can resemble sand or mud.

You can try flushing it with dishwasher detergent. Powdered version works best because it's low suds and dissolves well. Drain and fill multiple times to clean out the detergent and sludge before filling with new coolant
 
  • Like
Reactions: wydopenLb7

1FastBrick

Well-known member
Dec 1, 2016
2,261
865
113
Junkyard
That could also be from people not using distilled water or a premix coolant to top off the system. It likely wasn't maintained properly either... most people think its a con when you take a vehicle in for service and they recommend flushing the coolant. If I recall I believe it was 5 years or 100k miles that it should be replaced. They have an additive that is supposed to be used around the 2-3 year mark that is supposed to help it maintain its quality.

Those could be factory marks. The lower valve cover with the OK sticker was done at the factory. Full service Junk yards usually hard stamp parts and put paint marking around them to identify where to look for said mark. Some will put those heat tabs on cylinder heads and blocks to make sure you didn't over heat it in case it fails withen the warranty time.
 

lb7resto

New member
Jul 19, 2023
23
9
3
NC
I let this sit relatively untouched over the winter. Now that it has been warmer at night I have been getting back to it.

I have a prime suspect for my coolant getting blown out:

PXL_20240308_024020688.jpg

All of the injectors came right out of the cups nice and easy except for this one. This injector was pretty tough to get out of the cup after I pulled them both out of the head. Maybe that isn't abnormal and maybe the rest of the cups will look this cruddy, we'll find out soon.

I've also decided to go ahead and replace the injectors after seeing this:

PXL_20240308_024042149.jpg
I didn't get it to focus on the rusty crud but you get the idea and I'm sure you've all seen it before anyway. They aren't all as bad as this but they do all have at least a little rust.

I'm excited to pull these heads off and be finished with the tear down. I'm still torn between spending the $2500 on cupless heads or re-using these. Also I am pretty certain I am going to get brand new OE Bosch injectors, replace my FPR with a brand new Bosch one, leave my CP3 alone and maybe get a lift pump down the road. Since I don't have any plans to go for big HP with this, I'm just trying to keep it factree and get it going down the road again reliably.
 

blueshift

New member
Jan 29, 2024
21
15
3
Raleigh
Ha, I feel your pain. I'm also smack dab in the middle of replacing the injectors on my LB7 (though 'just' the injectors).

I'm honestly pretty surprised that it was running fine prior to teardown, because it had some similarly bad looking things going on with the cups (though mostly with the injectors seating in the cups; cups into the heads seemed alright). Whoever last had it apart clearly was pretty hamfisted about reassembly.

I think that crud in the injector inlet is 'mostly' from stuff falling into it while unscrewing and removing the high pressure line. That's what 2004LB7 was talking about earlier regarding carefully cleaning them out if you wanted to reuse them. Two of my 8 looked like that, the other six looked fine. Granted I'm in it specifically to replace the injectors, I don't think I'd chance reusing one if I was in there for something else and they looked like that.

One of the write ups I'd read suggested to put RTV around the HP line nut to the injector once everything was reinstalled, to keep water and debris from getting into that little cavity around the line. That sounds like a good idea to me, and I'm planning to do that to hopefully mitigate that risk, should I have to go back under the valve cover for some reason in the future.

The other more experienced guys here will be of better judgement than me, but your HP lines look fairly decent, so you may could get by with just cleaning them. Mine were badly rusted, so I just got a new set.

I'd also recommend at least checking the valve lash while in there. It takes maybe an hour to do. Mine with 260k miles ranged from 0.008" to 0.020", versus the spec of 0.012".

Lastly, take a good luck at all of the 'soft' fuel lines. There's the two bigger ones to/from the fuel filter, and then a handful of smaller ones around the FICM and CP3. Mine looked pretty bad, so I've got some new ones on the way. Figured there's no better time than now to replace those, while they're super easy to get to.

The little things like that will make me feel a lot better when I'm 2000 miles away from home on the truck....
 
  • Like
Reactions: 2004LB7

2004LB7

Well-known member
Dec 15, 2010
6,596
1,909
113
Norcal
Yes, debris in the injector port like you show is almost always from the crud around the nut and line falling in as it's unscrewed. I've successfully cleaned them out. Don't blow air in there to try and clean it. You will only push debris further in. Instead turn them upside down and tap the port on some wood to dislodge the debris. Then swish it around in some diesel and tap it again. They will normally come out spotless after a few times.

You can also do the threaded cups and rent/buy the tap and do it yourself and have something close to cupless heads in the end. Probably far cheaper too
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
3,986
1,125
113
Larsen, Wisconsin
I think you're on the right track but I would ask/maybe recommend a few things as a shop owner.

1) You're likely going to have a $500-$1000 bill at your machine shop for head work including pressure check, decking, checking and repairing valves/valve job/guides/seats. This makes the Fleece heads enticing as it greatly reduces their cost. You also can typically sell core head sets for $100-$300 a set.
2) OEM Bosch injectors are a great choice. The updated injector has some nice changes over the factory installed option when these trucks were built that does help extend life.
3) Personally I would replace the CP3 all together instead of just the FPR. At the age these trucks are it's likely not far behind everything else. A new OEM CPR is not overly expensive and can save you an issue down the road if your truck or pump is in higher mileage.
4) Inspect all of the soft lines on the engine (as advised by another member) as it's a great time to change them out if needed.


If you're not in a huge rush I am going to be selling a FASS 150 with ~10k miles on it off of my personal truck shortly (month or so).
 

lb7resto

New member
Jul 19, 2023
23
9
3
NC
You guys think it would be worth me sending the injectors to get tested and cleaned instead of replacing them? How can I tell if they're the updated design?
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
3,986
1,125
113
Larsen, Wisconsin
Personally I wouldn't waste my money on testing higher mileage used OEM LB7 injectors. Usually it's $50-$100 per injector to test so you're talking $400-$800 just to test them, if they're bad you still have to pay that money. In my opinion it's far better value to put that toward new injectors in this instance as stock VCOs are very cheap compared to oversized aftermarket injectors.

You won't be able to visually tell but unless they've been replaced in the 2017 or more recent timeframe they're the older design.
 

johnmyster

Member
Nov 6, 2023
67
25
18
Lynchburg, Virginia
I'd do every rubber line under the hood (coolant, fuel, and hydraulic) and use spring clamps (like the factory did) except the few places where a worm clamp is appropriate. Even if you don't want to go that far, please do that 3" long coolant hose that runs over/behind the fan pully bracket. The one that returns the turbo coolant back to the bypass tube. The ones in the valley can be tackled later but that one is a tough cookie on its own.

I guarantee the turbo thermostat has enough crud in it that it's stuck open.

Your water pump looks like it might be newer than the truck. Your harnesses also look like they aren't shedding brittle loom like mine were, before I redid everything I could touch.

An updated oil cooler if you have heavy towing aspirations?
 
Last edited: