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How to replace water pump (pics)

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472K views 365 replies 218 participants last post by  PeayM 
#1 ·
Lots of informative information has been learned from this site. Figured I would contribute.
03 Envoy. 106k. Had Fan clutch replaced once. 2nd Water pump.
Started hearing a grinding in the front. Fan and water pump pulley could be moved around by hand.

Total time 30 Minutes. Didn't drain coolant. Just used a catch pan.

1. Engine bay shot of water pump hidden. Ugh... (LEAVE BELT ON)

2. Remove radiator cap to relieve any pressure.

3. Remove upper radiator hose.

4. Remove both lower transmission lines and 1 of 2 10mm radiator fan shroud bolts.

4. Remove 2nd 10mm radiator fan shroud bolt. Disconnect black clip for fan clutch.

5. Make sure hood is propped up nice and high. I used a pry bar and wedged it. Get an open ended wrench to fit the fan clutch bolt. I used a 1 1/2". (Those specialty tools are junk). Its a little bigger, but all I had. Still worked fine.

6. Make sure the wrench is clear of the 4 water pump pulley bolts and fan.

7. Get a firm grip on the wrench, and take a hammer and smack it 1 good hard time to bust the nut loose. Make sure the hood prop is not up.

8. Spin nut off and press in on fan to lift over the threaded end. Continue to lift upward on the fan and shroud at the same time to remove as 1 unit.


9. You might hit the radiator neck, just press shroud towards engine on passenger side and continue to lift.


10. Once removed, loosen (do not remove) the 4 13mm bolts holding the pulley. (LEAVE BELT ON)

11. Remove belt out of the way, and finish removing bolts from pulley, and remove.


 
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#348 ·
CAN BE Replaced with Shroud in place

You do not need to pull the Shroud to replace the WP. Just did mine last nite outside in the cold.

I did remove the Shroud bolts to allow 2 layers of cardboard to be placed next to Rad to protect it.
Break loose Clutch & fan as described.
Remove bolts holding fan to Clutch fan, Allow Clutch fan to be postioned at bottom of shrould.
Remove pulley bolts, The pulley can be removed past WP nose.
Remove the 5 WP bolts. The water pump can be worked out.
Reinstall in reverved order.

Trans lines can stay connected, All wiring stays connected. I did remove the upper rad hose, But it really didn't even need to come out.
 
#349 · (Edited)
My Trailblazer at ~157K miles also needed the water pump replaced upon finding massive coolant leakage under truck after a cold morning. Just weeks prior I replaced the coolant and found the original radiator cap to have a bad o-ring so I replaced the cap. My theory, after finding the original water pump screws "loose" (easily removed with little torque) upon disassembly, is that replacing the original radiator cap with a new one increased the pressure on the coolant and forced a leak at the then "loose" metal gasket on the original water pump. The original water pump seals and bearings still seemed okay, however, I replaced it along with a new metal gasket. No sealant used just like factory. I did place a drop of blue loctite on each of the (5) pump screws and tightened carefully as it is an aluminum block. No torque wrench was quickly available, or really needed IMO.

Note: I agree with keddano, I prefer to access the water pump with shroud in place.
 
#352 ·
Helpful hint for water pump replacement

I just replace the water pump and fan clutch on my 2002 TB with 193,000 miles yesterday. When screwing the new pump on, you might want to replace the 5 10mm screws with new ones. I broke 2 off when torquing them in (89 ft/lbs). :duh:

The 5 bolts were $1.09 at my local Ace Hardware and well worth the hassle of drilling out and removing the broken bolts with a broken bolt removal tool which I had to do.

Other than that, this write up pretty much hits the nail on the head for someone doing this for the first time. I took me 3 hours to do, 1 1/2 of those was spent running around getting tools to remove my broken bolts. :crazy:
 
#356 ·
Thanks for the write up, but I couldn't break the fan clutch nut using the wrench and hammer method. Mine slipped due to coolant on the pulleys and belt. After I cleaned both, it still wouldn't bust, but turn the engine over.:bonk:

I found this method and it worked really well.

chevroletforum.com/forum/silverado-fullsize-pick-ups-21/how-remove-fan-clutch-without-fan-clutch-tool-55707/

I used the free end of a ratchet strap and taped it to the clean water pump pulley and hooked it to the lift point just above and to the right. I wound the strap up on the pulley and ad it held really well. It was a cinch to bust then nut.

I've changed the pump once before on my truck and used a big breaker bar and some wire cable to hold. This was much easier.

Enjoy!
 
#357 ·
Water Pump Replaced; Won't start/turn over to leak test

Long-time lurker, first time poster. Excellent instructions, and I agree with the hit-or-miss response to loaner tools. Thanks so much!

05' 4.2L TB 110K miles

I'd been putting off this repair for some time and finally got around to it, and finally got that damn clutch nut freed. When my coworkers asked me what I did over the weekend, I was this close to telling them "trying to bust a nut" but figured that'd land me in HR.:laugh:

After replacing the water pump, I wanted to run a basic leak test before embarking on the Fan Shroud Adventure. Battery is also starting to go, but I've got a jumpbox, and it does hold enough of a charge to not reset the clock.

When I go to start it, it doesn't attempt to turn over and is just a short electical whine. No clicking, etc. Did my ignition switch fail at the worst possible time? :( What else could it possibly be?

Also, how much coolant did y'all pour into the radiator cap before starting, or did you let the pump run dry to pull it through the reservoir? I know that might be a dumb question :duh: but didn't see a mention of it in the thread.
 
#359 ·
Water Pump ?

Hello,

I am going to replace my water pump, as well as well as fan clutch unit. Do you think while I'm replacing everything else I should replace the Coolant Thermostat and the Temperature Sensor? They both seem to be working
just fine in 04 Trailblazer LS has 155K on it so maybe wouldn't hurt just to replace all?
 
#360 ·
Hello,

I am going to replace my water pump, as well as well as fan clutch unit. Do you think while I'm replacing everything else I should replace the Coolant Thermostat and the Temperature Sensor? They both seem to be working
just fine in 04 Trailblazer LS has 155K on it so maybe wouldn't hurt just to replace all?


Good move. I should have replaced both at the same time, and I ended up taking it all apart TWICE instead of just once.

Though after I replaced the fan clutch, I've had no more limp mode errors.

Its extra work for the thermostat and temp sensor, not sure its needed unless its failing.
 
#361 ·
Stuck With This Sticky----- Please Help

This is an extremely helpful super write up. I managed to get stuck at the fan clutch removal. I was unable to make any progress in loosening the clutch nut removal using the 13" nut removal tool I rented from Autozone.

Left belt on as recommended, but never able to loosening nut. The drag on the old belt was not enough to hold the clutch nut tight enough to allow a hard smack to the tool to move the nut counterclockwise.

I had the idea of using the 3/8" ratchet on the tensioner to tighten the belt tension that didn't work either even using a breaker bar on the ratchet for additional idler back tension. I felt I should not continue fearing I might damage the idler.

So after a few hours of smacking, I decided to stop and post my deli a here to see if anyone can offer another means of holding the clutch pulley while breaking the nut loose.

I welcome and encourage your input. I could not find a 1 1/2" open end wrench as used in the video or would my crescent wrench open sufficiently to accept the flats on the nut, he se the rental tool from Autozone.
 
#362 ·
This is an extremely helpful super write up. I managed to get stuck at the fan clutch removal. I was unable to make any progress in loosening the clutch nut removal using the 13" nut removal tool I rented from Autozone.

Left belt on as recommended, but never able to loosening nut. The drag on the old belt was not enough to hold the clutch nut tight enough to allow a hard smack to the tool to move the nut counterclockwise.

I had the idea of using the 3/8" ratchet on the tensioner to tighten the belt tension that didn't work either even using a breaker bar on the ratchet for additional idler back tension. I felt I should not continue fearing I might damage the idler.

So after a few hours of smacking, I decided to stop and post my deli a here to see if anyone can offer another means of holding the clutch pulley while breaking the nut loose.

I welcome and encourage your input. I could not find a 1 1/2" open end wrench as used in the video or would my crescent wrench open sufficiently to accept the flats on the nut, he se the rental tool from Autozone.

I used the tool from advance auto. Looks like a big fork, with only two points on it. That went around the 4 bolts holding the pully on. Then the other wrench on the nut.
 
#364 ·
Thanks for the helpful writeup! I just changed my water pump, fan clutch, thermostat and hoses. While I was in there, I cleaned the throttle body and MAF sensor. All together, it took my about 2 and a half days, between thunderstorms, and visiting relatives. The bulk of the time was running around getting tools.

Removing the fan clutch and shroud was made easier by a tip I got off YouTube. When you're ready to remove the shroud, use two 30mm x 8mm bolts. You remove two opposing bolts from the fan clutch and replace them with the 30mm bolts. Remove the remaining two bolts on the fan. This will enable you to push the fan and clutch deeper into the shroud, giving you plenty of room to remove it.

As for loosening the fan from the pulley, I used a loaner 36mm wrench from Autozone. To keep the pulley from moving, I bought this spanner from O'Reilly Auto:

http://www.oreillyauto.com/site/c/detail/LIS0/43580/N1679.oap?ck=Search_N1679_LIS_1433813_3880&mn=Lisle&mc=LIS&pt=N1679&ppt=C0374

I still need to burp my system, as it seems I have some air trapped in there. I'm just letting it cool down before I get back on it.
 
#365 ·
I replaced my fan clutch and water pump as part of a total cooling system overhaul. I wound up going with the Duralast Water Pump and clutch fan kit. Combined with a mobile mechanic service he had the fan clutch threaded on in literally the time it took me to tell him to meet me around the garage door. In that approximately 45 seconds he had the fan clutch threaded on. I already had the water pump on with a roughly two hour curing time on the gasket sealant.

BE VERY CARFEUL on threading the fan clutch on.....trust me I went through three water pumps not counting the original water pump that was being replaced. Don't ask long story but as Hans and Franz would say......

"Listen to me now and believe me later"

After that matter of putting the fan shroud back on. Fan Shroud will go on much easier with two rods......Dremel Tool and Cut Off Wheel I cut the area around the radiator neck and it was much easier. There is no structural reason why the fan shroud couldn't be molded with the radiator neck already cut out but I wasn't at the design team meeting.
 
#366 ·
I have been researching this job for two weeks now since I got a full diagnostic from Chevy dealership and came back the thermostat and ran clutch, so might as well do the water pump too. 239000 miles.
I have no tools so I took it to a mechanic at 11 am yesterday got a call at 4:52 PM saying they spent the whole time trying to get the bolt off and it is completely stripped (by someone else they claim)
He told me since he is replacing the entire thing he may just saw off the bolt!!! He has even removed the radiator. But were calling it a day and would have to complete monday!


I was not expecting no car until monday
So now I am reluctant to let him SAW anything off. Is this okay? Should I tow the car to chevy or home to get another mechanic to do it. I'm in Orlando, Fl
 
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