how much is a duramax with a bad valve worth?

dirty max 2500

dirty max 2500

gutter butter
Oct 24, 2014
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california
Hi every body my LB7 was running good until my engine started knocking. .i took it to the shop they said cylinder number 7 was dead.it had a bent push rod and the piece on the end broke off..the truck still knock after the push rod was fixed..now the guy in charge of the estimates said it's the valves? They quoted me 4200$...they also said they won't know if the piston was affected until they take it apart..which will cost a lot more...iam also anticipating injector issues pretty soon cause I put about 90000 miles on it...i wanted to get a lly or lbz and sell my truck as is...how much should I ask for it? The truck is pretty clean except for a tear on the driver seat...
 
hondarider552

hondarider552

Getting faster
May 28, 2008
10,627
2
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34
Arizona
gunna take a pretty good hit on it if you sell it outright. I wouldn't pay more than 5k for a LB7 with a F'd motor, less if it had miles.
 
dirty max 2500

dirty max 2500

gutter butter
Oct 24, 2014
50
0
0
california
It's leather but it's a base model I think...it doesn't have power windows or seats.it sits six people and it's a extended cab...02 Lb7 6.6
 
dirty max 2500

dirty max 2500

gutter butter
Oct 24, 2014
50
0
0
california
. may be possible to find another engine. For example

;
what their charging for and to install a new motor.i feel like I might as well get a new truck..iam leaning towards a Lbz...thanks for the link though.
 
TheBac

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,529
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Find a decent running LB7 and swap it in. You could do it yourself for well under those estimates. Hell, if you're anywhere close to Russ, he may even be able to do it for under those estimates.
You may want to delve a bit deeper into the diagnosis first, too. If it is bad valve but the piston is ok, then either have that head gone thru or swap in another. Would be the same as doing a headgasket job.

It all depends on how much you like your truck, I guess.
 
dirty max 2500

dirty max 2500

gutter butter
Oct 24, 2014
50
0
0
california
Sorry I haven't logged on..I've been busy...so I decided to take my heads off...i just bought a cherry picker and engine stand...i gathered some tools also for the job..i know I can pull the motor but taking off the head seems complicated. I tried to search for threads but when I click on the search box it take me to the corner of the screen and I can't type.can you guys send me a good diy link? Also do you have to change the head studs..once again I'm new.i appreciate all the help and input..thanks for having patience.
 
Awenta

Awenta

Active member
Sep 28, 2014
4,090
2
38
CT
Pretty much keep unscrewing things till you see pistons. I would do arp studs but I don't know what your plans are.

I'd pull the motor. only other option is lift the cab, up to you.

Sent from my SM-N910V using Tapatalk
 
H

Hot COCOAL

May the farce be with you
Jun 9, 2012
4,433
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0
dirty max 2500 said:
Sorry I haven't logged on..I've been busy...so I decided to take my heads off...i just bought a cherry picker and engine stand...i gathered some tools also for the job..i know I can pull the motor but taking off the head seems complicated. I tried to search for threads but when I click on the search box it take me to the corner of the screen and I can't type.can you guys send me a good diy link? Also do you have to change the head studs..once again I'm new.i appreciate all the help and input..thanks for having patience.
Click to expand...

Just google it with the word "duramaxdiesels" in the title, that'll do it

Removing the engine and doing a swap isnt a bad job at all, make sure your engine stand is good for a minimum of 1000lbs, and even then support the engine when you're wrenching on it in the stand...

I bent mine taking off the balancer
:eek:

As far as where to get an engine, id seriously check with your local dealer, i got a GM reman long boock for 6k delivered, taxed and out the door... No need to pull any heads, set any valve lash or anything "complicated"
Just turning nuts and bolts

Just swap your accessories over and slap it in, done...new engine with 100k mi warranty

I think an LB7 can be had for more like $4800 too, and i know for me there were cheaper options than buying from the dealer, there was one or two places i could've gotten a shortblock for $3200 or a longblock for $4800, but they only had a 3mo warranty and some questionable practices...

Good luck man whatever you do, but id highly recommend you keep the truck and dig into the repair yourself, read as much as yiu can, keep your internet handy while you wrench, have a clean work area with space available for take off parts !!!label everything as you take it off!!! Put it into a plactic zip-loc bag and mark what it is, every set of bolts!!! Every set of nuts, headlight assembly, accessory bracket, ground bolt, trans bolt, dipstick tube hold down

Whatever it is label it!
Youll be fine
 
H

Hot COCOAL

May the farce be with you
Jun 9, 2012
4,433
0
0
Basically to remove the engine:

Unhook battery leads
Place hood in service position or remove it...neither is totally necessary but do help
Loosen the lug nuts on the front tires
Jack front of truck up and set on stands
Remove wheels
Remove fender liners
Remove intake
Remove front pipe to down pipe v band clamp
Remove trans dipstick tube
Remove downpipe
Remove starter
Drian oil and remove the oil filter (mine was in the way when i tried to remove the engine)
Remove flexplate to torque converter bolts through the starter mounting hole, turn flexplate with a stout screwdriver by accessing the flexplate through the trans inspection hole and engage flexplate teeth with screwdriver
Remove engine grounds and wire harness hold down bolts on block
Remove plugs from sensors in block
Remove headlights and park lamps
Remove grille
Remove headlight housing
Remove hood latch and set to drivers side
Remove hood latch core support
Remove upper core support
Unbolt trans cooler and let hang out of way
Remove fuel line quick disconnect
Unplug and remove glow plug module
Remove/loosen/free up engine wiring f om engine and disconnect ECM/TCM bale connectors and injector wiring harness
Remove main fan belt (serpentine)
Remove alternator
remove AC compressor and set it to passenger side
Remove cold side intercooler/CAC pipe
Remove hot side pipe
Drain radiator by removing lower radiator hose
Remove hoses
Remove upper and lower fan shroud
Remove fan from pulley, not necessary but helpful
Remove radiator
Remove intercooler
(You can remove the intercooler and radiator as one with your hoist)
Remove brake boost lines
Remove power steering lines
Use a grade 8 or 10 M12x 1.5 bolt and thread one into the back side of the passenger head, use another bolt and place through the bolt position for factory second alternator, these are going to provide your pic points
Free up any fuel lines and wiring connecting the block to trans
Remove transmission bell housing bolts...

This isnt needed to support the transmission, but if you jack the bell housing up a couple inches itll make it easier to pull flexplate out the transmission bell housing
Remove the engine mount bolts to frame, i found it easier to remove the engine with the mounts connected to the block
Pull the engine

Im sure i missed a few things...but you get the jist
 
Last edited:
Awenta

Awenta

Active member
Sep 28, 2014
4,090
2
38
CT
Or just remember where they go :)

I think you'll love your truck more when you put your blood and time into it.

Sent from my SM-N910V using Tapatalk
 
dirty max 2500

dirty max 2500

gutter butter
Oct 24, 2014
50
0
0
california
* #17*****

*Today, 05:33 PM

Hot COCOAL*

May the farce be with you

*

Join Date: Jun 2012

Truck: CC/SB

Engine: LBZ

Transmission: Automatic

Posts: 3,567

*Hot COCOAL's Garage


Feedback Score:*1*reviews, 100%

Basically to remove the engine:

Unhook battery leads
Place hood in service position or remove it...neither is totally necessary but do help
Loosen the lug nuts on the front tires
Jack front of truck up and set on stands
Remove wheels
Remove fender liners
Remove intake
Remove front pipe to down pipe v band clamp
Remove trans dipstick tube
Remove downpipe*
Remove starter
Drian oil and remove the oil filter (mine was in the way when i tried to remove the engine)
Remove flexplate to torque converter bolts through the starter mounting hole, turn flexplate with a stout screwdriver by accessing the flexplate through the trans inspection hole and engage flexplate teeth with screwdriver
Remove engine grounds and wire harness hold down bolts on block
Remove plugs from sensors in block
Remove headlights and park lamps
Remove grille
Remove headlight housing
Remove hood latch and set to drivers side
Remove hood latch core support*
Remove upper core support
Unbolt trans cooler and let hang out of way
Remove fuel line quick disconnect
Unplug and remove glow plug module
Remove/loosen/free up engine wiring f om engine and disconnect ECM/TCM bale connectors and injector wiring harness
Remove main fan belt (serpentine)*
Remove alternator
remove AC compressor and set it to passenger side
Remove cold side intercooler/CAC pipe
Remove hot side pipe*
Drain radiator by removing lower radiator hose*
Remove hoses
Remove upper and lower fan shroud
Remove fan from pulley, not necessary but helpful
Remove radiator
Remove intercooler
(You can remove the intercooler and radiator as one with your hoist)
Remove brake boost lines
Remove power steering lines
Use a grade 8 or 10 M12x 1.5 bolt and thread one into the back side of the passenger head, use another bolt and place through the bolt position for factory second alternator, these are going to provide your pic points*
Free up any fuel lines and wiring connecting the block to trans
Remove transmission bell housing bolts...

This isnt needed to support the transmission, but if you jack the bell housing up a couple inches itll make it easier to pull flexplate out the transmission bell housing
Remove the engine mount bolts to frame, i found it easier to remove the engine with the mounts connected to the block
Pull the engine

Im sure i missed a few things...but you get the jist

__________________


Thanks I found a similar thread..what about taking the head off once on the stand? Thanks hot cocoal
 
dirty max 2500

dirty max 2500

gutter butter
Oct 24, 2014
50
0
0
california
Can I check the balance rate for the injectors? in its current condition? You know with the bad valve?I was gonna put some new one in? It's been almost 100000 miles.
 
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