LB7 Water Pump Replacement DIY
 

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Parts:
Water pump

Minimum tool requirements:

Good socket set with atleast 30 inches of 3/8 extensions for starter bolts swivel extensions and u joint extensions.
Ratcheting flex head wrenches make life easier in tight areas.
10,12,14 mm sockets both regular and deep
15mm 3/8" socket for the starter
12mm wrench
screwdriver, retaining pin pliers or wire nippers, 90 degree needle nose pliers.
Something to protect Radiator from damage, wood cardboard, sheet metal. something gotta be there.
fan clutch removal tool from autoparts store, I used the 1-7/8 flat wrench and 90 degree needle nose pliers to remove fan clutch
3/4 drive breaker with big ass cheater bar and a 12pt 36mm or 1-7/16(36.5m) 3/4 drive socket
torque wrench that can do at least 260ftlbs.
one short half inch extension, really only need a 5 inch one.
large bucket or pan for coolant.
something to stand on work off of, its going to be a long day
dielectric grease/ motor oil for o-rings

And a good helper. and about 4-6 hours of your day.

1. Start off by disconnecting the negatives on both the batteries and start removing the upper fan shroud, the cover for it has a couple of push pins that hold it to the grille/fan shroud and you just need to remove the center pins on them like the fender liner pins.
2. While your doing that you can drain the coolant out the little drain plug located on the passenger side bottom corner and place a bucket underneath before you open up the drain. Attachment 56459
3. unbolt the TCM its on the driver side and its sitting on top of the upper fan shroud, it has two 10mm bolts holding it then unplug it and set it aside, i covered up my red and clear connectors form my tcm with a sandwich bag and rubber banned it and layed it asside.
4. remove the other two bolt from the upper fan shroud and there will be 4 push pins holding the upper shroud to the lower two on eash side about fan clutch height. pull the center pins out and pull out the upper fan shroud.
5. Now use the 1-7/8 fat wrench and the 90 degree needle nose pliers to remove the fan, it might be tough, be sure to wear gloves for this but i could the "proper" tool for that. Attachment 56460 now place some cradboard or something against the radiator so udont dammage it so you can remove the lower fan shroud, its real hassle but it does come out.
6. ok so its time to remove the passenger side fender liner and tire if you need more room and remove the unbolt the starter from the motor, you dont have to remove it just slide it away from the area. theres two bolts holding the starter to the block. Attachment 56461 The trick to getting the starter out is using about 30 inches of 3/8 extension and a 15mm socket for the bottom bolt mine was so loose i could take it out with my fingers so check that every so often. the top on is a little tricky too, a 15mm swivel socket/wrench/u-joint will work here.
7. Once thats out of the way, ur supposed to use a J-44643, but a half inch extension will work too, just have someone rotate the flywheel by using the 36mm/breaker to rotate the crank till you see a hole in the flywheel then stick the female end of the extension into the hole and have your buddy turn the crank like he was going to lossen it so the extension will stay snugley into place.
8. OK no i hope you ate a big breakfast cause this bolt is tight, i was told its locktighted and torqued down to about 500 ftlbs, but i hope you ate the whole box of wheates for this bolt. Use the 3/4 breaker about 60 inches of cheater bar and pull down on it to try a break the bolt loose an easy way to fit such a big cheater is to unbolt the hood with a 13mm and lift it up higher and rebolt it in the other slots for bolts in the hood. this make it to where u can make the hood stand straight up, Dont use a half inch you will break it. see look what happened to me Attachment 56462 Attachment 56463
9. once you got bolt off the balencer slides right off, its a heavy one so dont drop it.
10. Now to the pump one thing i did was remove the fan clutch pulley too from the block, it has about 3 14mm bolts and 2 14mm nuts on it, i used a 14mm wrench and stepped on it to break the nuts and bolts free and slide that out.
11. loosen the coolant hose on the bottom of the water pump and watch out for the coolant. undo the two bolts on the black pipe comming from the thermostat housing to the top of the pump and wactch out for the coolant spill and the o-ring if there is one keep a pan underneath so you can catch it. and there is two nuts on the oil cooler tube that are on the on the back side of the pump on the lower driver side of the engine theyre kinds hard to get to, but you can reach from below with a 12mm wrench or from the driver side fenderwell.
12. There will be 3 bolts left on the pump housing tha hold it to the block Attachment 56464 to get the top one kinda move the black pipe out of the way and try to get the bolt from the side with a wrench, its a little hard and a pain in the but but itl come out, this is the short bolt, the long bolt is on the bottom right of the pump and the nut is on the left side. with them out you can wiggle out the pump, and get it onto the table.
13. Theres 3 bolts that hold the pump housing together, use a 12mm wrench and someone to hold it to take it apart to replace the pump. heres a video http://s219.photobucket.com/albums/cc9/2500heavyduty/DIY/water%20pump/?action=view&current=100_2106.flv
14. There should be o-rings supplied and a gasket too for the oil cooler tube, lube it up with oil or dielectric grease and slide it on the "pump" side of the pump and tighten the bolts down to 14-20 ftlbs, nvm what i said in the video i had a brain fart. http://s219.photobucket.com/albums/cc9/2500heavyduty/DIY/water%20pump/?action=view&current=100_2109.flv
15. Install the pump and torque down the 3 bolts that hold it to the bock to 15ftlbs. the coolant tube nuts are torqued down to 18ftlbs and thermostat bolts are 15 ftlbs.
16. put back on the hose, and the fan pully mount bracket, torque them bolts to 45 ftlbs.
17. Torque down the harmonic balencer bolt to 260ftlbs and coat the threads on the bolt with red locktite, u dont want that comming off.
18. drank a beer
19. pull the 1/2 extension out the flywheel and torque down the starter bolts to 58ftlbs.
20. and put everything back together, they dont really need trq specs.
21. fill the coolant up with dexcool or something that is dexcool compatible, or u will mess up ur colling system, i bought about 5 gallons of 50/50 dexcool and poured it in and oppened up the middle bleeder bolt on top of the thermostat and tighten that back down to 20 ftlbs. and fill over flow tank to the cold level line.
22. and change your oil too your pump may have leaked coolant to the oil contaminating the oil.

Good luck

Awesome Writeup Dano.. Thanks for taking the time to make this, and share it with everyone.. Im sure many will appreciate it!

:c:

AWESOME DANNY !!! I know how much of a PITA it is to document things like this

THANKS MAN !!

i would have takes more pics, but i also replaced my power steering pump, pulled out my rad and intercooler and pipes and cleaned them all up, and i was workin alone so i was cusisn up a storm cause some of the stuff u need some patience for and i walked away many times.

But having someone there to help you is a big boost on something like this

Great write up!!!!


Good Job!:U::pca1:

You forgot something in step 8.....

Call me every few hours for suggestions and more tools to get the balancer bolt off. :argh:

My response.......just get angery with it. :ouch:

Excellent job, Danno. :U::U::U: Thanks for taking the time to do this. :c:

Good write up Danny, You want to do my truck next?

lol Yep, Tweety has sprung a leak too. :howdy:



:OT: BTW John- That overlay wont work for my truck. Wrong tach limit. :(

Oh yeah, It's a gas motor overlay,I guess we did not think of that.

He should put it on anyways. I can hear him now......'I can hit 5-grand anytime I want too.' :tttt:

:lol88: I'll even take video's. :pca1:

Nah im good :)

Awww, Help a brother out! You have experience now. It should be real easy!

i can help, ill even lend you my breaker and socket, but your going to have to do build a deck around the truck so it would be easier to work on

Hell, with Johns truck you outta be able to stand upright and have a straight shot at the balancer. :)

exactly what I was thinking.

that pump is a little tricky to get from below though , the top bolt behind the thermostat tube u have to get from the top

appreciate the write up. im fixin to change the pump on my 01.

Guess I'll be changeing mine in the not to distant future. Its not making any noise but I'm leaking a little.

mine leaked so bad i went though a gallon a day of coolant

I'm going threw about a quart a week. I'll mess with it in the next week or so I guess.

waterpump
 

I did a water pump on a 2001 today and found that if I removed the 3 bolts and 2 nuts (studs) on the fan mount I didn't need to take the fan and pulley apart.I just removed the oil filler tube (and plugged it to stop foreign material).After covering the rad with cardboard the whole fan assembly came straight up where the oil filler was.After the fan was out the lower shroud came out easily.
I also never removed the inner fender to remove the starter I just drove onto wheel ramps and had not trouble removing it.

LB7 Water Pump Replacement...
 

:U:

Man I am so glad to have found the info you posted. I am new to the diesel world and love my GMC Duramax. I had to replace my water pump after it had started leaking on a trip from San Diego, CA back to my home in Mobile, AL. It was sure a lifesaver. Thanks a lot!

Joe Martin

stick around, theres lots more info to be found

after helping a friend tear a duramax down to bare block and completely rebuilding it, i will never own one of these trucks, they are awesome, well built engines, but any truck that you got to remove the starter to replace the water pump is more than i want to deal with......

thanks for the write up good job helped me out a bunch :U:

In the words of Rodney Carrington "If you ever have the opertunity to do this jump off a F*&king cliff and hope theres rocks at the bottom because you dont want to live threw that shit." I'd like to find the genius who thought this out and kick him in the nuts.:argh::argh::argh:

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Took me about 3.5 hours to do mine. I also noticed the surgeing issue I had is gone and found out I had a boost leak I fixed while I was at it. Nice to not come out to a puddle under the truck.

cool. nice job. 3.5 hours is pretty quick for first time (im guessing that it was ur first time) :U:

First time doing one on a Max but I turn wrenches everyday so use to busting ass working on things. Would have been quicker if I didnt have to spend an hour looking for tools again.

i was just wondering why you have to take the harmonic balancer off to do this i am fixin to do one and i don't have the socket to remove it

There is a bolt behind the balancer to get the water pump housing off.

Thanks
 

An awsum right up I am so not looking forward to doing this job, but after all the horror stories Ive gotten your right up makes it seem like a regular day at work. Long but not insurmountable. Thank you, now if I could ony find a way to get paid to work on my own truck.:humm:

Thank you for the time you took to do pics and write up. It's the first info I could find after looking for three days. I couldn't even find a book at the auto parts store, but they'll sell you a book at the dealer for about $225.00:bat: Anyway thanks again, big help. I'm not sure what nut is going to break first trying to get the balancer off:s:. P.S. I got a quote of $1,450.00 to do the job. "No way am I ever going to pay that to put a water pump on." Almost rethinking that decision!!! not.

thanks for info and pics !!! would invest in platform ladder to work on truck!! have seen these online somewhere!!oh yeah and someone to stand on it ...lower back injury says i won't be able... but i'm a good supervisor lol!!

:rocking: I finished the :argh: pump. Wow, what an ordeal to put a water pump on. Definitely easier on the older trucks and cars. I can hardly wait to fix something else. It is kind of fun to conquer the unknown:rocking:!!! I think if I had to do it again, I could easily get it done in half the time. And you guys who claim they got it done in three hours are full of bad stuff. The tech book estimates 8 to 9 hours. Anyway, Love my truck, it's awesome.:c:

Thanks for the awsome post I join because of it. only one i could find that actually broke it down enough that i think i can get it done.
:rocking:

Im glad i found this cause i have to attempt this tomorrow. now is there any other tricks/tips/mods that we should do or other things we should look for while everything is out of the way? Like signs of wear on (fill in the blank) etc..... thanks. I have to say this forum is the most helpful. And good write up.:c:

wear on the inside of the pump housing is normal

So would it be wise to change the thermostat in the mist of all this?