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Water pump leak

Big T

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Made the 1200 mile trip from Fullerton, CA to Stevensville, MT just fine, but the truck has developed a leak from the water pump. Coolant is coming out from somewhere from the bottom of the pump and running down the driver’s side of the Fluiddampr. It is still leaking like this more than hour after shutting down. Should I assume the water pump is bad and order a new one? I have the spin on duramax fan. I think this was a 2000 model pump? Is that correct?

0D3E3ECA-438F-4A07-AE8F-6377259A2681.jpeg90A8BE7A-4656-4506-B8D1-6AD69ADBA220.jpeg2B99398B-355B-4F00-B7F1-42CBCCD03A10.jpeg
 

Big T

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AC Delco guy said there are a ton of knock-off parts being made. I would call and ask where appropriate suppliers are.


I would also verify itnis the weep hole before ordering.
What is the weep hole?

My wife is back in Socal, arriving here 8/9. This is the only car I have until Friday. I can top it off with distilled water for runs to the market. I will have my wife bring the wrench and pulley holder tool to remove the fan. I will be replacing the pump up here.
 

Will L.

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On the bottom of the water pump (all waterpumps) there is a small hole about 3/16” diameter. There is a seal to keep the coolant inside and when the seal fails the coolant gets to the bearings. Hot bearings spinning fast start getting coolant on them will destroy the bearings soon, and when the bearing locks up the shaft breaks and the fan assembly goes flying usually destroying the radiator, the shroud, battery, and whatever else it can play ninja against spinning at a couple thousand rpm. So they put the weep hole in the dead spot as an indicator to let you know something is wrong before one bad part becomes many expensive bad parts.

I would say 99% of the time coolant leak from bottom of water pump is needing water pump replacement. But it can be leaky lower radiator howe at the waterpump connection, or similar issue.

I agree putting a new timing chain on is smart at this point because you will have 95% of it off. Also the front main seal. Super easy to replace while the cover is off.

I hate doing water pump on the 6.5. For an engine that was set up to copy the small block chevy, one of the easiest waterpumps to change, the 6.2/6.5 is a mess.
 

MrMarty51

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I just use the appropriate size wrench that fits the fan hub nut, with the fan belt still on, use a largish size hammer and just knock the fan hub nut loose. Usually about three good licks with the hammer and it`ll then spin right off.
Leroy Diesel also has a real nice water/coolant pump that's suppose to flow better than any of them.
 

Big T

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On the bottom of the water pump (all waterpumps) there is a small hole about 3/16” diameter. There is a seal to keep the coolant inside and when the seal fails the coolant gets to the bearings. Hot bearings spinning fast start getting coolant on them will destroy the bearings soon, and when the bearing locks up the shaft breaks and the fan assembly goes flying usually destroying the radiator, the shroud, battery, and whatever else it can play ninja against spinning at a couple thousand rpm. So they put the weep hole in the dead spot as an indicator to let you know something is wrong before one bad part becomes many expensive bad parts.

I would say 99% of the time coolant leak from bottom of water pump is needing water pump replacement. But it can be leaky lower radiator howe at the waterpump connection, or similar issue.

I agree putting a new timing chain on is smart at this point because you will have 95% of it off. Also the front main seal. Super easy to replace while the cover is off.

I hate doing water pump on the 6.5. For an engine that was set up to copy the small block chevy, one of the easiest waterpumps to change, the 6.2/6.5 is a mess.
They show a timing cover gasket set with timing cover seal:

1596027971619.png

Is that the seal you're referring to, or is it the main crank seal behind the Fluidampner HB?

God this is growing into a bigger project. I really do not have the time to do this. Last time I did this (water pump and timing chain) was 10 years ago when I bought the truck. LIke I said, only have the one vehicle right now. Well I can't tear it apart until I get the parts.
 

FellowTraveler

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They show a timing cover gasket set with timing cover seal:

View attachment 61529

Is that the seal you're referring to, or is it the main crank seal behind the Fluidampner HB?

God this is growing into a bigger project. I really do not have the time to do this. Last time I did this (water pump and timing chain) was 10 years ago when I bought the truck. LIke I said, only have the one vehicle right now. Well I can't tear it apart until I get the parts.
BARRS LEAK has a heavy duty leak stopper w/pump lube even their ginger root tabs will generally stop the leak, in fact GM used the ginger root tabs to get all the northstar motors past the warrantee time frame....screwing countless poor souls who had no idea.
 

Will L.

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Problem is, although it may seal the seal that is wearing/ worn out, it also seals some radiator tubes and the all important head passages get restricted.

if you are in a bind and have to keep going, crack 2 raw eggs into the system. I had to do it in death valley once. the egg flows around everywhere and when it goes out the opening (like pump seal or pin hole in radiator) it expands and cooks solid near instantly. Then you can use any generic flush and it will remove it all easily from the rest of the system so nothing stays plugged or restricted long term.
 

Big T

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Never did get an answer to my question whether you are suggesting to replace the crank seal behind the HB?

Parts have been ordered.
 

MrMarty51

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To Me, them speedy sleeves on the harmonic balancer is not a good thing. Sometimes te seal comes with the sleeve, that seal is the same inside dimension as the stock original seal and, in My opinion, rather You ask for it or not, is too tight on the spedy sleeve and usually cuts the sleeve in no time flat, then it leaks worser than ever.
I took my HB to the machine shop, the said that because it is a diesel engine and the compression so much higher than a gasser, they would not machine down the seal surface area on the HB and install a sleeve that would be back to dimension, so, the next option is the one I use most of the time, use a bolt, warshers and a nut through the HB, chuck the bolt into the drill press, fire up the drill press and then use emory cloth and sand the sealing area until it is smooth and any ruts is polished mostly out. The seal will fit a little looser but it will not get tore up. nor wear through a sleeve and will last a very long time, other wise, replace the HB is the next best option.
 

FellowTraveler

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To Me, them speedy sleeves on the harmonic balancer is not a good thing. Sometimes te seal comes with the sleeve, that seal is the same inside dimension as the stock original seal and, in My opinion, rather You ask for it or not, is too tight on the spedy sleeve and usually cuts the sleeve in no time flat, then it leaks worser than ever.
I took my HB to the machine shop, the said that because it is a diesel engine and the compression so much higher than a gasser, they would not machine down the seal surface area on the HB and install a sleeve that would be back to dimension, so, the next option is the one I use most of the time, use a bolt, warshers and a nut through the HB, chuck the bolt into the drill press, fire up the drill press and then use emory cloth and sand the sealing area until it is smooth and any ruts is polished mostly out. The seal will fit a little looser but it will not get tore up. nor wear through a sleeve and will last a very long time, other wise, replace the HB is the next best option.
I actually had a brain fa_t and was thinking of my 5.9 Cummins when I made that statement about the crank sleeve....on the GM 6.5td.
 

Will L.

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I’ve used speedy sleeve on many things, ever had any issues.
True you should expect the seal to leak in less time than normal with whatever shaft is perfect, but if running a speedy sleeve it means the shaft area is grooved enough it would leak at least that soon then anyways, normally sooner.
 
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