Head gaskets or something else?

Nitro2020

New member
May 6, 2020
4
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0
Washington
My local shop just informed me that my 2004 lb7 with 183k miles on it needs head gaskets. So far the only symptom has been pressure in the coolant overflow tank. I already had injectors done about 20k miles ago, as well as the water pump about 5k miles ago. The job is just over $6,600 for head gaskets (including studs). I have also been told from family to look into getting a rebuilt long block motor shipped and have it replaced. That would be about $8,000 to do.
Is one more worth it? I have been told by a couple shops that this is a solid engine and insists that I have no need to do an engine swap.
The other option is to trade it in as is for another used duramax (we need a truck) but we have been told the trucks after this one have more issues and that this is the most desired truck.
Any advice on what route to go?

Also, upon further reading on this forum, could the problem be something else, or even nothing since the truck is running good with no smoke? I have added about 1/2 gallon of coolant since water pump replacement. Overflow tank threw up some coolant after a 400 mile drive (half of which towing 4500 lb trailer) and sitting for a couple days. Replaced overflow cap, then drove 50 miles locally with no trailer. Overflow tank hissed with coolant rising a little when opening cap (after sitting overnight). Ideas on my next step?
 

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
2,650
13
38
Central OH
$6k for a head gasket job? Any way you could do it yourself? And I'd skip the studs too

No need to do an engine swap. I'd lean towards the head gaskets being bad, when I've seen an injector cup come loose they'll leak pressure into the coolant much worse than what you described. But others may have a different experience, there's only so many ways to pressurize the coolant.
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
13,610
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Mid Michigan
If you didnt "burp" the cooling system when you did the w/p, you can easily add that much coolant to get it full. If the upper hose isnt hard like Torque says, then you probably do not have an issue with h/g's.
 

slowlml

Undercover Epa agent
Feb 6, 2015
552
38
28
Strasburg Va/Wardensville Wv
6600 is steep for a headgasket job imo. Where are you located?
Also i agree with tom about burping the system. If the upper rad hose isnt hard then its usually not head gaskets.
 

KyleC4

Tech
Dec 30, 2016
371
13
18
Bay Area
6k? Wow. I’m not charging enough lol. Follow what these guys have said about radiator hose after over night sit. And if injector cups were leaking, I always see some intermixing of coolant and oil
 

Nitro2020

New member
May 6, 2020
4
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Washington
The radiator hose was stiff (squeezable with effort) after sitting, but not rock hard. So far, 6k is the cheapest I have found. The other 2 shops I called wanted over 8k for the head gasket job. I do not have the time, tools, or experience to do the work myself. I am located in the Gig Harbor area of Washington.
 

Mxz8002003

New member
May 23, 2020
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Its possible you could have an injector cup leak. Ive seen it on my old mans lb7, though it was hg end up being a couple cups..
 

scott_willerscheidt

New member
Jan 30, 2019
26
3
3
48
gig harbor wa.
What shop in gig harbor? When the time comes, I'll be doing the work myself.

2002 gmc sierra 2500hd quad cab short bed
Zone 3" kit
285/70/17 Nitto Terra Grapplers
17x9 Raceline 930's
S&B intake
3" turbo horn
PPE boost valve
MBRP 3" downpipe
MBRP 4" exhaust
LED conversion
Edge CTS2 with SAS EGT probe
boost auto towing mirrors ( dual function)
fass 90
 

scott_willerscheidt

New member
Jan 30, 2019
26
3
3
48
gig harbor wa.
I know this is 5 months old but was wondering if you found out what the problem was and what shop you took it to do the work?

2002 gmc sierra 2500hd quad cab short bed
Zone 3" kit
285/70/17 Nitto Terra Grapplers
17x9 Raceline 930's
S&B intake
3" turbo horn
PPE boost valve
MBRP 3" downpipe
MBRP 4" exhaust
HSP hot/cold side pipes
LED conversion
Edge CTS2 with SAS EGT probe
boost auto towing mirrors ( dual function)
fass 90
EFI live spade jack
dmax store stage 3 allison
 

N2BRK

Active member
Dec 31, 2009
1,581
19
38
856 NJ
The best way is to test the system under a load while driving. I've had several people tell me that I need headgaskets because in the morning you can open my cap and there's pressure. I hooked up a gauge and watched under WFO and checked after sitting cooled. I don't need headgaskets.
 

scott_willerscheidt

New member
Jan 30, 2019
26
3
3
48
gig harbor wa.
Thanks for the reply

2002 gmc sierra 2500hd quad cab short bed
Zone 3" kit
285/70/17 Nitto Terra Grapplers
17x9 Raceline 930's
S&B intake
3" turbo horn
PPE boost valve
MBRP 3" downpipe
MBRP 4" exhaust
HSP hot/cold side pipes
LED conversion
Edge CTS2 with SAS EGT probe
boost auto towing mirrors ( dual function)
fass 90
EFI live spade jack
dmax store stage 3 allison
 

mojito5000

New member
Aug 19, 2019
25
0
1
Oregon
I just got done replacing my motor due to a bad head gasket that caused a cylinder to hydro-lock and bend a rod, so I'm well versed in this area...

95% of the time, the head gaskets on LB7 are the cause of pressure in the coolant system. If you are going to get down to the cups, there's really only a few hours of work to get the heads off and back on (other than machining). The hardest part of the job (for me) was setting the torque on the head bolts, and I ended up buying a huge 1/2" drive wrench off amazon to help with that.

Some pressure in the coolant system is by design, but you should be able to shut off the truck, come back in 15 minutes and be able to squeeze the hose to about 1/2 to 2/3'rds the original size with not much force. When I had bad gasket(s) I could squeeze the hose some (I lied to myself for quite some time because of this), but not like I can with good head gaskets. This is for a stock engine; for race engines, all bets are off when it comes to pressures.

Most shops here in Oregon are about $5k for a head gasket job, using head studs. I was looking to do it for about $1k (head studs are expensive) for just the parts. My engine swap ended up costing about $5k, after having to replace the injection pump. I still go out there after a drive and do the squeeze test and just breathe a sigh of relief.
 

Ne-max

I like turtles
Nov 15, 2011
3,307
26
48
Lincoln, Ne
5-6k is normal when doing head gaskets if it's a reputable shop. Especially with machine work. When we do them all rubber lines in valley get replaced. Usually glow plugs are shot. Good time to toss in Thermostats.
 

Dozerboy

Well-known member
Jun 23, 2009
4,367
54
48
TX of course
5-6k is normal when doing head gaskets if it's a reputable shop. Especially with machine work. When we do them all rubber lines in valley get replaced. Usually glow plugs are shot. Good time to toss in Thermostats.
Yep that’s what the good shops around here charge. They are going to pull the engine and reseal the top end and look for other issues while the engines out.
 

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