How to replace the water pump


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Total time, about an hour. On the OS someone claimed to have done it in 30 minutes, but it took me about an hour from getting everything out to having everything packed away.

Make sure the engine is COMPLETELY cool before doing this. Best bet is to do it first thing in the morning.

Remove the radiator cap and upper radiator hose. Make sure you have a catch pan under the truck to collect the antifreeze. You don't need to drain the radiator unless you are doing a flush and fill at the same time.

There's a variety of methods people use to loosen the fan clutch, but I will say you don't need a special tool. A 2' length of chain, M8 x 1.25 bolt, a quick link and 36mm open end wrench will work.

Take out one 13mm bolt from the water pump pulley and attach the chain to the pulley using the M8 bolt. Attach the other end of the chain to the engine lift bracket and using a 36mm open end wrench, loosen the fan clutch nut.

Once you have it loosened, remove the 10mm bolts from the top of the radiator shroud and the fan electrical connector (just a bit to the right and below the shroud bolt).

Remove the AC lines from the clips on the radiator shroud on the left side. Remove the fan clutch nut from the water pump. You'll be able to move the fan a bit to clear the shaft.

Pull the radiator shroud and fan assembly out in one piece. You can move the shroud forward on the left side to clear the radiator neck. Be careful not to smack the radiator with the shroud as you'll damage the fins.

Obviously, if you're just replacing your fan clutch, this is where you'd stop and do what you need to replace that...but, that's not what I'm doing here, so, onward. Remove your serpentine belt completely.

You can now undo the remaining 13mm bolts from the pump pulley and remove the pulley itself. You might want to leave the chain attached to the pulley so it doesn't spin when you're trying to undo the bolts. As you can see I didn't and had to reattach it, but now that the fan etc is gone there's a lot of room to work.

Once you've got the pulley off, remove the 10mm bolts holding the water pump on...make sure you have the catch pan under the water pump to catch the anti freeze.

One dead water pump. You can't see that there's anything wrong with it, but it ate it's bearings.

Installation is the reverse of the removal. Make sure you clean the surface where the water pump sits. The gasket only goes on one way, so if the holes don't line up, flip the gasket around. The water pump bolts only need to be hand tight...89 inch pounds, so don't swing off them. The pulley bolts get torqued to 18 ft pounds.

New pump installed with the pulley and belt reattached. Reattach the chain so you can get the pulley bolts to the right torque.

Now is a good time to wash down everything with clean water to remove the antifreeze that you's no good for paint etc.

When you're putting the shroud and fan back on, make sure that the pins on the bottom of the shroud go into the locating holes, you'll have to get under the truck to see and align them.

Be careful when you reattach the fan clutch nut to the shaft, the threads are fine and it's really easy to cross thread them. There is a torque spec for the fan clutch nut, but you're not going to get a torque wrench in there, so go with the German torque setting...gud an tight. Remove the chain and put in the last pulley bolt.

Plug the fan electrical connector back in, put the shroud bolts back and replace the top radiator hose. Top up the radiator with either Dexcool diluted 50/50 or whatever antifreeze you're running and do the normal burping of the system checking for leaks while you're running the truck.

All said and done, about an hour and it's really quite simple.


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@Matt What an Amazingly Clever Idea for a Specialty Tool... and Marvellously Economic set of R&R Procedures and Images! ... And so you've earned Serious Props from anybody that has to do this Job...(Pretty soon now...That will be ME!)

Thanks for what is...One Perfect "Write-Up".


Well-Known Member
Yep, the chain method worked well for me too. Also I don't think you need to torque the clutch nut at all -- provided your fan is turning in the opposite direction to the tightening direction. Put a bit of anti-seize (I use a kind of copper paste) in the nut, thread it on and then spin the blade by hand until the nut reaches the end. All the subsequent starts & runs of the engine will do their job and torque it more than you'd need :wink:
Great write up! A couple of tips to add:

- Cut a "slit" in the fan shroud where there radiator hose neck goes so it clears it when sliding the shroud back in. Might also avoid damaging that radiator neck.

- As mentioned by @dkvasnicka , anti-seize on the fan clutch will help you for later removals. And once it's threaded in right, leave it loose by a couple of threads. When you start the engine, it will self-torque since the pump spins in the required direction.


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I'm glad I'm not the only one who decided to "violate" my truck and cut a slit into the shroud :biggrin: I was just too afraid of the GMT gods to talk about it here :biggrin:
No, seriously, it really helps a lot when taking the shroud out and lowers the probability of you bending your blade. And as we all know, taking the shroud out is not something you do just once in the course of the ownership on GMT360... :whistle:


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Getting ready to do this job. Actually my 02 EXT has what it I think is a bad WP, lots of play, it's a beater and may be sold soon. So, as preventative maintainence, I'm going to do it all right on my 06 EXT DD and swap it's good used parts to the 02. (Actually all started as a Alt RR on 02 and noted bad WP play, so had locally rebuilt Alt done it'll go to 06 as well).
Anyway, I bought all ACDelco parts from RA (rec'd today). Surprise! ACD WP # 252-822 $35 listed as "professional"is made in CHINA and only comes with a paper gasket. I read in another thread to order ACD metal gasket separately another $12, even Felpro is paper though. Any thoughts on this? All old school engines use paper. Another note, the ACD WP # 251-731 is listed as OEM but is about $84, hope it comes with stock metal gasket lol.
Also RR tensioner, idler, WP pulley, rad cap, T-stat, temp sensor, U&L rad hoses, belt, and doing drain/flush and fill with new dexcool.
I am not using the chain method. I already contacted "Toolguy1954" on eBay as recommended by Mayo04 and bought the home made tool to hold the clutch bolts. Only about $14 shipped and I already have the entire lift bracket removed to RR the above mentioned ALTs.
Great write up and pics! Definitely will help me.
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Just because it's "made in China" doesn't automatically mean it's junk. It could have been built to ACDelco's specs and pass their QC. There is not a single brake rotor or drum produced in North America anymore. They're all made in China. But I digress.

For the gasket, I don't use it. I use RTV. That's what's used between the block and timing chain cover so why not on the WP? I haven't used a gasket on them in over 20 years (exception for imports that use an o-ring).


Well-Known Member
Just because it's "made in China" doesn't automatically mean it's junk. It could have been built to ACDelco's specs and pass their QC. There is not a single brake rotor or drum produced in North America anymore. They're all made in China. But I digress.
I agree, not automatically, but usually lol. I worked an auto parts store chain in the Midwest during the initial influx of China made parts. In regards to rotors/drums, we carried a premium line made in the USA (some in Canada) and the cheap line made in China. Almost every Chineese rotor I checked for true on the lathe were out .08" or more - some were potato chips, the N Amer rotors typically under . 01, barely enough to make a clean up pass that would matter. Our machine shop offered free lathe work, all the shops and alley mechanics we supplied would get the cheaper rotors/drums and then have us turn them to true.


Silver Supporter
Somethings up with photobucket. ALL of my pics are no longer there and they were the only copies. I've contacted them and we'll see what happens. If I can get them back, I'll relink them from elsewhere.

As an aside, why can we just drop photo's straight from a hard drive?
The biggest problem is that they have to be reduced before they can be uploaded directly to the forum. I use Windows Image Resizer (an old XP Powertoy that has been ported to Win 7+) and if it's on my phone, I just email it to myself and it reduces it automatically.


Well-Known Member
Started on my pump / clutch replacement... following this good thread. The "chain idea" was a great idea as the tool loaner wrench kit for the clutch nut was only for a ford which appear to have "huge nuts"... :smile: Anyways, got things loose now.

One question: Does unbolting the power steering pump so the lines can be move back further help any with get clearance from the rad upper neck? I see pictures of people cutting the neck shorter along with notching the shroud but was hoping to not "mod" the front.

Another question: I don't recall seeing / reading much on the "puzzle of removal" but was wondering IF one disconnects the for bolts on the fan blade and moves the fan blades forward and then undoes the clutch nut, is there enough room to then "wiggle" out the clutch thru the "top opening" if one can move the shroud forward enough to create a gap between it and the rad? Just wondering... my guess would be no. But then wondering, if you can lift the shroud on the right side enough to create the gap / opening? I like puzzles... :smile:

OOPS... I see crawling under to check the lines, that those lines attached to the shroud are tranny lines so the power steering pump effort isn't going help.

OOPS... still further I see that this isn't a post but an article, sorry if I screwed things up.
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Haven't heard of cutting down the rad neck before. I've notched all of my shrouds and is barely noticeable after install. What I do is use a suction gun to pull coolant from the filler, disconnect the hose and pull the shroud with the fan. You pretty much have to pry the tranny lines back to get them to clear the clips on the shroud.


Well-Known Member
thanks.... I tried to "uncoupling" the fan blades from the clutch plate (4 bolts) BUT then trying to slide the blades along the shaft didn't want to move. Not sure why. I will try the notching on the shroud with a oscillating tool. In terms of the "shortening the neck"... it was on one of the videos somewhere.... I guess they need both "combinations" to get by the shroud out. Hopefully, those tranny lines are more solid than they look (walls I mean), rust around them is ominous.
The fan is an interference fit on the clutch hub for centering it. If you rock the fan, it should eventually let go. Sometimes corrosion plays into it.


Well-Known Member
well stranger than fiction... :-O I was getting my oscillating tool setup and was moving the shroud around to figure out how much to cut out.... plop, the clutch release the fan blades and fell forward on the rad (a few marks on the fins, hopefully nothing major). Anyways, moving the right side of the shroud forward and up allows you to reach in lift out the clutch with a bit of "finagling" and then you can do a little "finagling" on the shroud and its out. I guess I was "half right" about taking the clutch out first thru the right top side.
Greetings everyone. Longtime lurker, first post. Love this site, I'm a refugee from the "other site." I am in the middle of doing the water pump and wanted to add a trick for loosening the fan clutch nut. My apologies if it already posted elsewhere. I use a 12" (opens to 36 mm) adjustable wrench, as tight as possible on the nut (oriented to the pass side between the blades and bolt heads, so the force applied will be downward). I use an air chisel with the V groove tip, and straddle the end of the wrench handle with it. A couple of light burps with the chisel on the wrench and the nut is easily freed. I am also unable to find info on the wp gasket, RTV? The only gaskets available to me locally (need it now) are the one that came with the new pump (A.Z. Duralast awp-9234;paper) and paper Felpro. Old gasket was metal, no RTV. AC Delco probably. Doing research, there isn't much info out there, so I'm going old school and RTV'ing the new paper gasket w/ a thin coat. Seems the "beaded" metal gaskets don't need sealant, but of course no one stocks them. Business as usual. Hope this helps.
I have used the air chisel right on the nut but on the wrench is also a good option.

I just used RTV, no gasket. Either way, it shouldn't leak.

"Refugee". I like that! :crackup:
Thanks for your reply and advice! I didn't see it until I was done. I usually RTV gaskets. I learned wrenching on older iron where you had to seal everything. The TB (03, 243,000 miles, have had 8 years) is the newest truck I've had. The basics are the same as older vehicles, but I've found sometimes the TBs have very specific procedures where the normal rules don't apply. I'm still in the 70's + 80's:smile: That's one reason this forum rocks, getting those specific details to do things right. I needed her going yesterday and I did'nt realize the RTV (permatex WP T-stat housing gasket maker) needs 24 hrs b4 putting into service. I figured lack of info on the gasket was info itself, so I rolled the dice and used the gasket dry. So far no leaks, but we'll see. The suction pump on the upper hose: great tip! saved me from the normal coolant puking. I like to keep things as neat as I can, prefering clean rust! Thanks again! I'll update about the gasket performance soon.
Update on "dry/no rtv" on Autozone Duralast AWP-9234 water pump. FYI for anyone: 300mi 90 degree + driving in hills of southern Ohio, no leaks. Next time however if time allows I will use RTV to be extra sure; as I tend to over-think and worry too much. Don't want to have lake Dex-cool on our fine roads!
I hear you. Duralast wasn't my first chioce (some of their products are OK, some are junk. Learned that the hard way with their CV axles) DuraLAST and comps are about all I can get local. Already plan on ordering from RA b4 winter. I forgot to thank Matt for the great write-up! Helped alot:2thumbsup:


Active Member
I have always used the adjustable wrench fan clutch but a little different than previous posts. I leave serpentine belt on and turn the wrench to 12 oclock, then a well placed smack with a hammer on the wrench in the correct direction (opposite direction of engine rotation). Has worked on every vehicle I've ever encountered.
Seen and used that method but there are times where the chain method is required with additional brute force. The 10+ years and rust tend to weld things to each other fairly well. Before this thread came out, the smack method wouldn't work on my Saab so I resorted to the air hammer. That eventually worked but destroyed the hex, which didn't matter since it was being replaced.

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