How To: LBZ Water Pump Replacement

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Super Moderator
Mar 13, 2012
southern cali
sorry i didnt get pics of everything but you will get the just of it.first things first. you need to drain your coolant

next you start out by popping off the two 13 mm bolts that hold on the fan shroud and pull the plugs holding the top cover of it off. once thats removed you will need to pop off the 3 13mm bolts that hold on the protective shroud around the fan. there is one on the top and one on each side. its pretty tight but i used my ratchet wrenches and it was alot easier.

next up i got out my air hammer

take it to the clutch on the fan and you're going to want to hit it counter clockwise. it will become loose enough for you to spin it off.

once you have the fan and shrouds out of the way, you need to remove your belt

now this is a little trick i learned instead of having to remove the start to lock up the flex plate. go under your truck on the drivers side. pop off the inspection plate on the trans. now wedge a bar or something that will stop it from turning into this little hole in the flexplate.

and this is what it looks like from afar

i used a ratchet strap to hold it up so i could do this by myself. but having another set of hands would be much easier.

now once thats secured. its time to take off the harmonic balancer. it is a 36mm 12 point socket. i have a 1" breaker bar since i heard of people break 3/4" drives so i wanted to be safe. but you want to spin counterclockwise again and use a breaker bar if needed. this thing is torqued from the factory at 250 ft/lb so its not easy.

heres the balancer and bolt you're taking off

once the bolt is off you want to pull the balancer off as well. be careful as its heavy and you dont want to drop it and crack it or anything.

next step is taking off the lower coolant line located under the truck

pull it off using a 5/16" socket(regular hose clamp)

make sure to have a bucket to drain the excess coolant into as it does get kinda messy.once thats drained its time to take off the pump

there is a black pipe running from the pump to the thermostat housing that you will want to take off. both bolts are 12mm and then there is a clamp on the hose. i would suggest replacing this hose while you're in this deep just for precaution. once that is off its time to remove the pump

there are two bolts and one nut on the front of the water pump. all 12mm

then, you're going to want to go through your passenger side wheel well so take out the plastic liner. then you will see a nut located here

now on this pipe there is another nut on the opposite side that is easiest reached from the bottom of the truck.

these nuts are both 12mm as well. take both of those off and you're going to pull the pump out exactly straight. if you tile it backwards or any way you can drain coolant into your oil and you'll have to do an oil change too. there will be excess coolant in the pump. once the pump is removed take it to your bench and there are 3 12mm bolts holding it together. once you get it apart it looks like this

put the new orings on each side of the pump. put the 12mm bolts back in and its time to reassemble. now reassembly is basically this write up backwards. the only thing you will have to do is rewedge your pry bar or whatever you use in the flex plate to be going the opposite way for when you tighten the harmonic balancer.

then all you gotta do is fill it up. make sure theres no leaks and air out your system and you're good to go. now again sorry for not taking a million pictures but if you have any questions just let me know and i will help you out best i can
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