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Old 01-27-2008, 01:51 PM   #1
mckey73
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Exclamation Coolant Leak

When I pulled in the parking lot at work last night I noticed a leak under the front tire on the driver side. I couldn't really tell what it was at first so off I went to the car wash. Made it about 1/2 a block and the low coolant light came on so I turned around. The problem I have now is I can't tell if it's leaking at the lower hose or from the water pump? The hose clamp was a little loose but I tightened it and drove home (28 mi.) and it's still leaking.

Help!
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Old 01-27-2008, 02:27 PM   #2
TheBac
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Water pump. Same exact thing happened to me. The weep hole is right behind the lower hose mount. If its leaking that bad, get it changed out soon.
Oh...its fun to change, too. Better have a 3/4 rachet/cheater bar/36mm socket for the balancer. Also have air hammer or 1 7/8 wrench for the fan nut. DO NOT remove the black thermostat-to-water pump pipe like I stupidly did.

Toman and Merchant told me a trick to keep the leaking to a minimum until you can change it out....remove the o-ring on the overflow cap. The system wont build pressure that way. Its a temporary measure til you can get the pump replaced.
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Old 01-28-2008, 12:17 AM   #3
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Tom that's not what I wanted to hear, but thank you for the advice. So that whole thermostat crossover pipe can stay there? If that's the case then the whole generator mounting bracket doesn't need to come off either, right? Did you drain any of the coolant? Any other tricks you figgered out?

Thanks alot for your help, I really appreciate it.

Jay
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Old 01-28-2008, 02:33 AM   #4
TheBac
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This is how I did mine. Took me 6 hours -- yeah, I already got grief from Merchant about my slowness. Your procedures may vary.

Parts:

water pump (with housing or not)
both pump o-rings, the gasket for the oil cooler feed tube, o-ring for the lower thermostat pipe connection (these should be with the new/remanned pump)
Optional: 4" piece of 3/8" heavy-duty hose for thermostat bypass (behind the balancer) and a new o-ring for the upper thermostat pipe connection (Merchant used an LB7 injector sleeve o-ring, they are tougher than the regular ones)
4 or 5 gallons of 50/50 Dexcool or equivalent ( I used the Peak Global Dex-compatible stuff)


You'll need these tools:

3/8" and 1/2" ratchets/ 16-20" extension (3/8" rattle gun also comes in very handy)
10,12,14 mm sockets
12mm wrench
15mm SWIVEL socket (for the starter bolts)
screwdriver, retaining pin pliers or wire nippers
Large piece of heavy cardboard, thin plywood or sheet metal (to protect radiator)
air hammer or pipewrench/cheater bar or 1 7/8" wrench (for fan nut)
3/4" ratchet/cheater bar/36mm 12pt socket for balancer
Torque wrenchs -- inc one that can go up to 300ft lbs (3/4")
KentMoore J-44643 flywheel tool or something to hold the flywheel in place
large pan for coolant
something to stand on while working
dielectric grease for o-rings
A supportive friend and plenty of beer.



1) Remove pass side tire. Remove inner fender liner. I also disconnected the negative battery cables.

2) You dont have to take the starter OUT, but it does have to be separated from the engine. Using the 15mm swivel on the 16" extension with the air gun helps greatly here. Top bolt is easy to get to. Bottom bolt is not....you have to go through the small area between the upper and lower control arms, behind the shock. Its just next to the diff mount. Starter will only move enough to free it from the block. Its a tight fit in there.

3) If you have that J-44643 tool, install it in place of the starter, using the starter bolts. If not, try to get a 1/2" extension into one of the holes in the flywheel. Make sure the extension is seated well.

4) Time to drain coolant. This is an ugly messy job. Do me a favor and put the o-ring back on the cap if you removed it earlier. You loosen the rad cap to regulate the flow of coolant. The Dmax radiator drain is just next to the lower intercooler boot on the pass side. Its a simple plastic twist fitting. The messy part comes from the fact that theres no petc*ck integated into it. You loosen it up and it sprays coolant 360*. Make sure you have a large, deep pan.

5) As the coolant is draining, you can start working underhood. You'll appreciate the stand now. I used a 3 foot bar stool. I removed the top plastic rad cover to get at the upper fan shroud. Remove the TCM -- two 10mm bolts and unplug it. Set it aside. To remove the upper fan shroud, there are two other 10mm bolts along the top, and 4 push pins connect the upper and lower fan shrouds. Use the nippers or the pin pliers for the pins. Unhook the A/C line from the shroud clip. Remove fan shroud.

6) Install the cardboard, plywood or sheet metal over radiator. If you dont do this step, you had better be EXTREMELY careful from now on.

7) Remove the fan. It'll be tough if its never been removed before. Have your helper use the 1/2" ratchet to tighten the belt. You have to hold the pulley against the loosening force. When you're looking at the engine from the front, you want to loosen the nut toward the pass side of the truck. The air hammer is a life saver here. Just hammer the left side of the nut with the A/H to loosen. If you have to use a wrench, it'll take some effort. Maybe using some liquid wrench between the nut and pulley will help. You'll get it. After you loosen the fan, it'll just twist off...be careful when you get to the end of the threads. The fan weight will want to swing it into the radiator.

8) Remove the serpentine belt.

9) I removed the fan support/pulley after this. There are five 14mm fasteners, 3 bolts and 2 nuts. It pulls straight off. Leave the rubber insulation in place if it stays on the block.

10) Hope you ate your Wheaties, cause now its time for the balancer. The 3/4 ratchet, cheaterbar and 36mm socket are the only way, unless you remove the radiator and use a high-torque rattle gun. You may need your friend's help to get it started. 260ftlbs is a heck of a pull. After you remove the bolt, the balancer should slide right off. SHOULD. If it hangs up, just work it back and forth and it'll come. Watch out, its heavy. Again, this is where the cardboard comes in....watch the radiator as you pull the balancer off.

11) By now, the coolant should be low enough to work on the water pump.
Remove the lower radiator hose. The clamp is integral to it. You may have to use a pick tool or the screwdriver to separate it from the pump.

12) Loosen the two 12mm bolts that hold the thermostat pipe to the top of the water pump. You dont necessarily have to remove this pipe to get the pump out. I wanted to replace my bypass hose during this install, so I removed the pipe. If you do remove the pipe, make sure you have a replacement o-ring for the upper seal. Like I stated above, an LB7 injector sleeve o-ring works perfect. If this o-ring gets cut, you'll have a big mess later on. More on that later.

13) There are two 12mm nuts holding the oil cooler tube to the back of the pump. IIRC, you can access them through the drivers side wheel well, or you can be a contortionist like me and get them from under the truck and from the side. Its not an easy task. They are not torqued on very tight, thats a plus.

14) Remove the water pump. There are two 12mm bolts, one on top and one on the right side. They are two different lengths, so remember which one went where. There is also a 12mm nut on the lower left. This PITA nut is the only reason the balancer had to be removed. The pump needs to be wiggled out. You'll be amazed at all the coolant still in it. If the oil cooler tube gasket stuck to the tube, make sure to pull it off.

15) If your replacement is just the pump (no housing), there are three 12mm bolts holding the two together. Dont forget to lightly lube the o-ring with dielectric grease before you put the pump back together. Torque the bolts to 16-20ftlbs.

16) Install the pump. Dont forget the new gasket to the oil cooler tube. Dont forget the pump o-ring, too (lube lightly). Tighten the bolts and nuts on the cooler tube and pump to 16-20ftlbs.

17) Reinstall the thermostat pipe. Replace the hose if you choose to. Dont forget the o-ring between the pipe and the pump. If you took the pipe out, replace the upper o-ring, and use some dielectric grease on the inside of the thermostat HOUSING, not the o-ring itself. You dont want to roll or cut that o-ring (like i did). The pipe will kind of "click" into place in the thermostat housing. Be very careful not to cut the o-ring, and double check that the o-ring is seated. Tighten the bolts into the w/p to 16-20ftlbs.

18) Replace the Lower radiator hose.

19) Replace the balancer. Torque to 260 ftlbs. I actually went a bit past that...275...I'm paranoid. Blake also showed me the GM torque specs...they say to torque to 74ftlbs, then tighten 105* past that. I think he tried it once and found it was closer to 280-290ftlbs.

20) Replace the fan pulley/support. Torque the bolts/nuts to 45 ftlbs.

21) Replace the serpentine belt.

22) Replace the fan. When you get it snug, use the air hammer and just touch the nut on the right to tighten it. It doesnt need much. The turning force of the accessories fully tighten it back up.

23) Remove the cardboard/wood/sheet metal. Replace the upper fan shroud. Clip the A/C line back in. Replace the TCM. Replace the upper radiator cover.

24) Back to the wheel well. Remove the extension or flywheel tool. Replace the starter. Torque the bolts to 58-60ft lbs. Reconnect the negatives on the batteries.

25) Make sure to tighten the drain on the radiator. Replace the wheel well liner and tire.

26) Fill cooling system. You MUST use Dexcool or a type that is Dex-compatible. DON'T use regular green anti-freeze unless you swapped it completely out sometime in the past! (this involves flushing the entire system twice with plain water and is a real PITA) If you mix the types, you'll end up with a brown goo throughout the system and a blown motor later. I've seen it happen.
There is a 12mm bleeder bolt on top of the thermostat housing. Loosen that bolt. Fill system with fresh Dexcool (or equivalent) until it comes out that bleeder, then tighten bleeder 16-20ftlbs. Fill overflow tank to full cold level.

Clear tools, start truck and look for any leaks. Refill coolant tank as needed until all air is out of the system.

If no leaks, then crack open a beer and celebrate.
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Old 01-28-2008, 02:45 AM   #5
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One other thing....check your oil. If its milky, that means theres coolant mixed in it. I recommend changing it.
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Old 01-28-2008, 03:54 AM   #6
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Dang! You're crazy! That's one hell of a write-up and I can't thank you enough! Sounds like I'll be working my ***** off tomorrow.
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Old 01-28-2008, 10:48 AM   #7
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You're welcome. I did forget some things, so please re-read it. (mostly about coolant)

After my "experience", I thought it'd make a decent thing to write about. You gave me the impetus to do it. What that engineer was thinking when he put that one retainer behind the balancer, I'll never know. Also, I hate the single-nut fan design. Just dumb engineering. It would be a simple 2 hour job if it wasnt for those two things.

Went to Autozone and got the big ratchet ($32) and socket ($10). Harbor Freight had the torque wrench ($75). I bought my water pump at NAPA. The only one they had in Michigan was a reman with a lifetime warranty for $68. Not that I wanted to use a reman, but beggars cant be choosers, and a new pump is $225.

It was a total PITA for me. I at first tried to do it in my garage. But I got to the fan and couldnt remove it, even with an air hammer. So I buttoned everything back up and called Eric. He said to bring it on over (after he got done laughing his *ss off), and that I could use the shop. So I took that Tuesday off work and drove to Holland. Thank God I did. They were extremely helpful, because every 15 min or so, I'd stop and have to think, "OK, what do I do next?" Thats why it took so long. Also got to see the "new" shop he'll be moving into....its HUGE!

This is why I stress watching yourself around that upper pipe o-ring.... I had that darn thing break on me during install and didnt know it. Got everything done, filled with coolant....started truck and coolant sprayed EVERYWHERE. Had to go back and replace the o-ring, which involved taking the front of the engine apart again (except the balancer). Another 2 hours later, I was done. This time, I asked Eric to pressure-test the system before i put the front of the engine together, since he had that capability. Checked out fine, so I finished up. Total 8 hours on replacement. Heck we didnt even have time for a beer afterward, as it was 8pm and I had to get home.

Good Luck.
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Old 01-29-2008, 03:13 AM   #8
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Ok Tom, your last post was the deciding factor, I'm going to take it to a professional. Maybe I'll be able to swing a fluidampr at the same time. I can get a new pump from gm for $167.

I really still appreciate your time for the write-up and will pass it along to the shop guys. Not all of us are lucky enough to live within driving distance to Eric's shop. My garage is a mess and I have too many other things on the go for at least the next month. I am missing out on the opportunity to buy more tools though.
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Old 04-07-2008, 04:13 AM   #9
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Thanks!!!!!!

Wanted to give a big thanks to mckey73. That was an awesome write up. I am helping my buddy to do this job to his 2004 Silverado 2500 HD. We subscribed to ALLDATAdiy.com and eAutoRepair.net and read up what they had to say, but they don't include the info on specific tools such as the 36mm 12-point socket. They also don't provide alternatives to the J-44643. We got the fan off and hit a stopping point when we didn't have the right socket for the harmonic balancer. We had to go to the internet to find what size socket and how to hold the flywheel. Reading your post was very informative and encouraging. Appriceate it much!!!
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Old 04-07-2008, 11:10 AM   #10
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Tom, could you make this water pump change into a sticky?

Tony
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