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Discussion Starter · #1 · (Edited)
Hey guys, im trying to diagnose why my thermostat replacement (that worked for 1 week) is now causing the water to leak from the water pump area (I put blue gasket maker around the thermostat housing when I reattached the thermostat the second time so theres no way its leaking from the housing) and I have heard people mention the weep hole from dying water pumps but I cannot seem to find it on my truck. can someone please point it out in this picture? this appears to be the style water pump I have except its specified as a 2.05 inlet whereas mine is the 1.88 diameter thermostat inlet. it is also possible that the gasket has been breached and water is leaking from behind the pump which is making things quite hard to diagnose sorry for the wall of text my "enter" key isn't working at the moment. Auto part Automotive engine part Engine Automotive super charger part Automotive starter motor

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well I just got out from underneath the truck and to the best of my inspection I can either assume that its leaking from the gasket or the bottom of the pump has a crack in it because water is "welling" out of the bottom in a way that would either be inidicative of a slight crack in the equipment or a breach of the gasket. mind you that, the truck was only slightly temping up then cooling itself down, which led me to believe it was the thermostat in the first place, then after replacing the thermostat everything was fine for a week (not even a raise in temp) and then I started noticed coolant slowly leaking out from under the truck then a few days passed and the coolant leak kept getting worse and worse.
 

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What year is your truck? I have 2002 and mine is leaking from the gaskets on the water pump. I was told by a GM tech that it was common.
 

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My 2003 leaked from the gaskets also. I did a pressure test and it poured out at around 12 psi. I installed a new pump instead of just changing the gaskets. My dad's 02 leaked from an o-ring sealing a cover on the back side of the pump. You can buy a new o-ring for it. He also just chose to install a new pump after taking it all apart.
 

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Yea im due for a pump right now on my 01, i plan on doing the hoses while im there.
 

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Discussion Starter · #5 ·
Sorry about that, i got a 2004 model, y'know i just checked my "profile" and its listed under vehicles but that part doesnt show up underneath your forum handle, i just put it in the "location" instead, now everyone can see it

I will likely be replacing the entire pump as well as the gaskets, but im worried because I cant afford an OEM one, and i dont want to buy some POS from Autozone (whether new or remanufactured)

What are yall's opinions on the remanufactured or new but generic water pumps that go for ~75-150?
 

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Rockauto has ac delco for $125 for steel impeller, im just saving up til i can afford all the hoses. Going to be about $200 for the quality stuff. Still have not made up my mind on which brand to use for hoses. I also tried to find a high volume wp with no luck.
 

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I think stated this before. the water pump gaskets should be replaced. they are a known failure with these engines. replacing these are easy. replacing the water pump is a much harder job since the fan must be removed. on removal of the water pump you will clearly see the weep hole. also if you remove all the components around the water pump and using a good sized mirror with a light in a dark setting you can see the weep hole. when the gaskets leak the coolant flows around many seams on the block so it is hard to find exactly where its coming from.

the fastest easy way to know if its these gaskets is to use some coolant sealer .If it stops then its the gaskets . if it does not stop it is the water pump seal/bearing.
 

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I think stated this before. the water pump gaskets should be replaced. they are a known failure with these engines. replacing these are easy. replacing the water pump is a much harder job since the fan must be removed. on removal of the water pump you will clearly see the weep hole. also if you remove all the components around the water pump and using a good sized mirror with a light in a dark setting you can see the weep hole. when the gaskets leak the coolant flows around many seams on the block so it is hard to find exactly where its coming from.

the fastest easy way to know if its these gaskets is to use some coolant sealer .If it stops then its the gaskets . if it does not stop it is the water pump seal/bearing.
Hey man. I just read this. I have a leak in a water pump, weep hole I think. The pump was replaced about 4 years ago for the same thing. I don't believe the pump is bad. Are you saying in your post that the pump can be removed from the block without removing the pully?
And are you saying to put some coolant stop leak, like blue devil, in the radiator? I'm looking for the easiest fix. Any detailed advice would be greatly appreciated.
 

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not much water pump weep hole leaks on these .. as you say you think it is the weep hole well you have to find out where it is leaking exactly .. cannot fix weep hole leaks on the cheap.. not gonna happen.

go to auto part store that has you WP... see how it looks LOL............
 

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not much water pump weep hole leaks on these .. as you say you think it is the weep hole well you have to find out where it is leaking exactly .. cannot fix weep hole leaks on the cheap.. not gonna happen.

go to auto part store that has you WP... see how it looks LOL............
I just went ahead and put a new pump on and no leaks...for now, lol
 

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I believe it was the gaskets. I saw on another forum to try torquing the bolts, which I did, but I also broke a thermostate bolt head off, so I said f-it and just replaced the pump. The pump I pulled off looked fine, but was wet on block below pump, so I believe it had to been the gaskets.
 

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I believe it was the gaskets. I saw on another forum to try torquing the bolts, which I did, but I also broke a thermostate bolt head off, so I said f-it and just replaced the pump. The pump I pulled off looked fine, but was wet on block below pump, so I believe it had to been the gaskets.
the WP on my 2000 5.3L is quite big and the bolts very small. so I did torque those bolts with torque wrench .. about 15-18 ft lbs ..over time these long and small bolts will stretch.. got to be careful when you tighten the hardware ..
 

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Discussion Starter · #14 ·
Looking back on this it was a terrible idea.

What i should've done was waited for engine to cool and dry then wiped my hand behind the pump and checked for residue or stain... Indicative of a breach whether it's the gasket(s) or the weep hole is insignificant at that point because the pump is coming off either way

The manual says to tighten those bolts in a 2 pass sequence likely for the reason jcat stated above
 

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Hey guys, im trying to diagnose why my thermostat replacement (that worked for 1 week) is now causing the water to leak from the water pump area (I put blue gasket maker around the thermostat housing when I reattached the thermostat the second time so theres no way its leaking from the housing) and I have heard people mention the weep hole from dying water pumps but I cannot seem to find it on my truck. can someone please point it out in this picture? this appears to be the style water pump I have except its specified as a 2.05 inlet whereas mine is the 1.88 diameter thermostat inlet. it is also possible that the gasket has been breached and water is leaking from behind the pump which is making things quite hard to diagnose sorry for the wall of text my "enter" key isn't working at the moment. View attachment 53169

- - - Updated - - -

well I just got out from underneath the truck and to the best of my inspection I can either assume that its leaking from the gasket or the bottom of the pump has a crack in it because water is "welling" out of the bottom in a way that would either be inidicative of a slight crack in the equipment or a breach of the gasket. mind you that, the truck was only slightly temping up then cooling itself down, which led me to believe it was the thermostat in the first place, then after replacing the thermostat everything was fine for a week (not even a raise in temp) and then I started noticed coolant slowly leaking out from under the truck then a few days passed and the coolant leak kept getting worse and worse.
Make sure you guys alwaysm, always drill an 1/8 hole in every thermostat you ever install for the rest of your life. It could save your motor someday. Trust me!
 

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Make sure you guys alwaysm, always drill an 1/8 hole in every thermostat you ever install for the rest of your life. It could save your motor someday. Trust me!
decades ago T stats had problems because we had to drill a small hole in these cheap T stats.
in the 1990's and now I did not have to drill a hole in it. never had any issues with engine temps ... I have a scan tool on my truck and the temp locks in at 190f... I only use distilled water and 65% antifreeze ..I never changed radiator heater hoses and radiator hoses.. water pump radiator no leaks no failures .. trucks 20 years old.
when GM put in dirty water in my truck , cooling system I had to flush out that GM crap... truck was new 2000.. now I did flush it once , and coolant when I replaced , it looks like new ..ac heater works great ..
 
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