LLY: Coolant leak, best approach?

frankenstien

Member
May 25, 2015
587
2
18
Fairbanks,Alaska
Backed my truck down from the house to the garage at my in-laws last night, pulled in the garage and had coolant running out of the front of the truck, looked under there, and looks like the pipe that connects to the water pump is leaking.

there was a bit of coolant everywhere, so i wiped it down and drove it home a couple hours later, wasn't leaking this morning, so i drove it to work and looked at it there, oh yes its leaking, out of the bottom bolt area of where that tube connects to the water pump

is it better to just pull the water pump or take off the oil cooler assembly at the back of the motor? I have seen most people take the oil cooler off, but I also saw there's an o ring on that pipe on the cooler end that might be a headache.

with pulling the water pump, probably upgrade it to a welded/pinned one while i am there, as the truck has 133k on it and I plan on keeping it.

anything else i should be looking at/for? T stats are about 4 years old, maybe time to replace them as well?

no issues with the truck, leak just kinda showed up.

thanks,
Mike
 

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Eddie_LLY

Member
Jul 28, 2014
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0
6
Colorado
You sure it's leaking from the hose connection to the pump housing and not leaking out the weep hole from the pump? Sure sounds like that's what you've got goin on. Likes to let loose after running for a bit, shut down, splashdown.

When my water pump was on it's way out it didn't leak much when running but as soon as it was shut down it dumped coolant.

As far as the rest of your post idunno. Replace the pump with a pinned one for your mind's sake, and as far as T-stats go 4 yrs doesn't sound that old if it's been cooling properly before the pump decided to have a problem. ( I left my 11yo T-stats in when my water pump died because they were working fine...I'll surely be regretting that some day but that day ain't today)
Good luck, I'm still regrowing a finger:spit: from my water-pump job at the beginning of August
 

frankenstien

Member
May 25, 2015
587
2
18
Fairbanks,Alaska
You sure it's leaking from the hose connection to the pump housing and not leaking out the weep hole from the pump? Sure sounds like that's what you've got goin on. Likes to let loose after running for a bit, shut down, splashdown.

When my water pump was on it's way out it didn't leak much when running but as soon as it was shut down it dumped coolant.

As far as the rest of your post idunno. Replace the pump with a pinned one for your mind's sake, and as far as T-stats go 4 yrs doesn't sound that old if it's been cooling properly before the pump decided to have a problem. ( I left my 11yo T-stats in when my water pump died because they were working fine...I'll surely be regretting that some day but that day ain't today)
Good luck, I'm still regrowing a finger:spit: from my water-pump job at the beginning of August

it might be? i tried to look for /at the weep hole, but couldn't see, but the bolt in the upper left of the pic,that goes to the oil cooler was where i was thinking it was leaking from, not where the lower hose connects, if I'm understanding you correctly
 

clrussell

pro-procrastinator
Sep 23, 2013
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Replace pump and make sure you use a metal style gasket to the oil cooler pipe.. Not the crappy paper one some water pumps have in them.
 

frankenstien

Member
May 25, 2015
587
2
18
Fairbanks,Alaska
Replace pump and make sure you use a metal style gasket to the oil cooler pipe.. Not the crappy paper one some water pumps have in them.

roger that, i watched a couple videos where they were using a red paper gasket, looked cheesy to me

I started tearing into it this morning, don't have a cheater pipe here to get that balancer bolt off so thats where I am at, looks like last time it was apart they just used silicone to seal the pipe into the top of the water pump, is that normal or should there be a gasket there?

also thinking of doing a few other things while Im in there, swapping to a van t stat housing, clear that pipe off the top of the motor, as it will have to come out again when i have to do my cp3 this winter.

how critical is the torque spec on the balance bolt? i dont have a torque wrench that goes near that high
 

c20elephant

C20ELEPHANT
Apr 25, 2013
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Phoenix, Arizona
roger that, i watched a couple videos where they were using a red paper gasket, looked cheesy to me

I started tearing into it this morning, don't have a cheater pipe here to get that balancer bolt off so thats where I am at, looks like last time it was apart they just used silicone to seal the pipe into the top of the water pump, is that normal or should there be a gasket there?

also thinking of doing a few other things while Im in there, swapping to a van t stat housing, clear that pipe off the top of the motor, as it will have to come out again when i have to do my cp3 this winter.

how critical is the torque spec on the balance bolt? i dont have a torque wrench that goes near that high

The "pins" used on the Duramax crank gear, reluctor wheel and the balancer are merely guide pins for positioning and no way shape of form do they keep the balancer and crank gear from rotating on the crank. It's the torque of the bolt that keeps it "sandwiched" together to keep them from rotating/spinning on the crank and shearing the pins. I would say it is absolutely critical to keep it from shearing the pins or at least close to the required torque specification...
 

SoCalMike

Member
Dec 12, 2010
758
16
18
SoCal
I thought the bolt gets torqued to 74lb ft and then 105 degrees.

How are you guys measuring 105 degrees after you torque the bolt to 74lb ft?
 

Woodster

Computer Nerd
Aug 28, 2009
176
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16
Utah
I'm having the same issue, but in reverse...kinda. I just replaced my WP with the Danville "pinned" version and Mishimoto tubing and shortly after it started leaking from the exact same bolt. I get a few drops on ground in the morning but it's not too bad. I really don't want to tear it all apart again. :baby:

Probably due to the gasket as I used the reddish paper one.
 

frankenstien

Member
May 25, 2015
587
2
18
Fairbanks,Alaska
got it all apart this morning, only thing that looked odd was on the inside of the water pump cover, some "wear" on the inside, guessing its just from the way the water flows inside the housing?

on the bypass pipe that goes into the bottom of the thermostat housing and into the top of the water pump, there's a small maybe 3/8'' hose that comes off it and goes to another small metal pipe, what is that rubber hose called? i have been looking through the net as well as www.partszoneonline.com, no luck

going through and replacing some hoses while its all drained down
 

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frankenstien

Member
May 25, 2015
587
2
18
Fairbanks,Alaska
Got my water pump in the mail on friday, kit came woth a paper gasket for the pump to pipe flange, going to hit the dealer tomorrow and see if they have the metal one, if not, probably just going to have to use that paper one, need to get the trucl up here soon.

Anyone use the paper pump to pipe that comes woth the ac delco water pump with good results?
 

IOWA LLY

Yes, its really me
Feb 23, 2007
2,275
4
0
Paper gasket sucks. If your stuck using it, use a little bit of the gm gray engine sealant (silicone) on both sides of it.

Sent from my SM-N920V using Tapatalk
 

frankenstien

Member
May 25, 2015
587
2
18
Fairbanks,Alaska
went by the dealership today, they had the metal gasket. hopefully start putting it back together tomorrow, boiler decided to take a poop today, so had to get that squared away.

waiting on an upper radiator hose also, going to give the van housing and hose a try and relocate the TCM
 

frankenstien

Member
May 25, 2015
587
2
18
Fairbanks,Alaska
finally got some time to work on it today, any suggestions on the coolant tube that goes into the top of the water pump? i thought i had it in, but it pinched and split

any suggestions appreciated
 

clrussell

pro-procrastinator
Sep 23, 2013
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Hard to explain but you have to push in and twist.. And use good lube... Ky or vasoline works well.


And yes I'm talking about the black pipe into the tight gray hole..





On the top of the water pump.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,670
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Phoenix Az
I thought the bolt gets torqued to 74lb ft and then 105 degrees.

How are you guys measuring 105 degrees after you torque the bolt to 74lb ft?

each point on the bolt is 30* (360* divided by 12 is 30*), the valley of the point is half way between each point (15*). so you mark a bolt point to the washer and balancer, then count 3 points and a valley counter clockwise and and mark that valley. boom, 105*. 9/10 times the wash never turns after the 74ft lbs inital torque but still mark the balancer to be sure it doesnt turn

The "pins" used on the Duramax crank gear, reluctor wheel and the balancer are merely guide pins for positioning and no way shape of form do they keep the balancer and crank gear from rotating on the crank. It's the torque of the bolt that keeps it "sandwiched" together to keep them from rotating/spinning on the crank and shearing the pins. I would say it is absolutely critical to keep it from shearing the pins or at least close to the required torque specification...

the pins do in fact keep the balancer, crank gear, reluctor wheel, and cam gear from spinning. if they were not, GM would have used a tapered fit with the pins/key way still but only as alignment guides. The stock pins are just weak and can not take a whole lot of force. Under stock situations, they do the job just fine in keeping everything located. if what you say is correct, all we would need is a ARP balancer bolt and cam bolt to keep any rotation from happening but that is not the case and the reason built engines get 5mm key ways put into them.

Hard to explain but you have to push in and twist.. And use good lube... Ky or vasoline works well.


And yes I'm talking about the black pipe into the tight gray hole..





On the top of the water pump.

yeah that sucker can be a b***ch. same with the steel tube into the thermostat housing. if you pull that tube out and the truck has any kind of years on it from use, just go to the dealer and get a new oring. the old one will be so swollen and stretched out from the coolant, it damn near never goes back in.