Water Pump Leak

[Rowdy Dalton]

I noticed, a couple of days ago, that water was dripping from under the truck. I replaced it 6 years and 30,000 miles ago. So, I was hoping it was the pump. I drove it again, the next day, and nothing. It wasn't until it was fully warmed up, that it started spewing from under the truck. i couldn't see it coming from the pump, but figured that was where it was coming from. After struggling with the tensioner, and getting the belt off, the pump spun fine, and the bearings were tight. After the pump was removed, the rubber gasket looked like crap.
I replaced the pump with a cheap O'Reilly Special. The one with the redesigned shroud over the impeller. I heard somewhere that this helps with cavitation.
Before anyone gets their knickers In a twist, I didn't have time to wait several days for a "Good Pump".
Question: Since it spins fine, and is still tight, could the issue just be the gasket?? Are gasket failures common on these?

 

[dusturbd]

I noticed, a couple of days ago, that water was dripping from under the truck. I replaced it 6 years and 30,000 miles ago. So, I was hoping it was the pump. I drove it again, the next day, and nothing. It wasn't until it was fully warmed up, that it started spewing from under the truck. i couldn't see it coming from the pump, but figured that was where it was coming from. After struggling with the tensioner, and getting the belt off, the pump spun fine, and the bearings were tight. After the pump was removed, the rubber gasket looked like crap.
I replaced the pump with a cheap O'Reilly Special. The one with the redesigned shroud over the impeller. I heard somewhere that this helps with cavitation.
Before anyone gets their knickers In a twist, I didn't have time to wait several days for a "Good Pump".
Question: Since it spins fine, and is still tight, could the issue just be the gasket?? Are gasket failures common on these?

I have seen a number of the gaskets take a crap

 

[seafish]

I have seen a number of the gaskets take a crap

That's highly doubtful as there are no "gaskets" on the Cummins water pump...it mates to the block using a thick high quality O-ring.

In fact, while Im sure it is possible, I have NEVER heard of thr water pump O-ring failing causing a leak, EXCEPT when the original was inadvertently left on t he block and the mechanic didnt realize it and ALSO installed the replacement O-ring that comes with the water pump. Using TWO O-rings will definitely prevent a proper seal and cause a leak, but that doesn't seem to be the case here.

Rather then a leaking gasket, the usual cause of a seeping water pump is failure of the internal bearing seals which will then cause bearing corrosion and eventually catastrophic failure of the water pump, most likely at the most inopportune time.

All that said, the Cummins water pump is both accessible and also EXTREMELY EASY to replace, requiring only a ratchet or wrench for the two bolts, a way to dismount and remount the serpentine belt, as well as a replacement water pump and O-ring.

That said, any member here will HIGHLY recommend using only the OEM Cummins water pump over ANY other aftermarket water pump, even the one made by Gates!!!

While you have the serpentine belt off, you should also carefully spin and check each and every pulley that it runs around for either roughness or play. ALSO the belt tensioner should be replaced if it has substantial high mileage on it.

Just my .02

 

[petersonj]

Ditto what @seafish says on the "gasket". Only an o-ring there. Static o-rings don't leak.

Also, when it comes to coolant leaks, the best practice is to pressurize the cooling system with a radiator pressure tester when the engine is cold. This procedure will take the guess work out of where the actual coolant is leaking from.

Leaking coolant can be difficult to pinpoint without a tester. Coolant will follow irregularities on the engine block and accessories. It can evaporate when the engine is warm making it seem like it stopped. It can start or stop leaking on a whim especially when the engine is heating or cooling.

I am not necessarily sold on the Cummins water pump. While my OEM water pump (Cummins) was still operating fine at 216,000 miles, I replaced it before a leak started. The Gates water pump that replaced it has now logged over 150,000 miles with no issues.

I personally know of there different Dodge Cummin owners of two 2003 trucks and one 2004 truck where the OEM (Cummins) water pump failed - one less than 70,000 miles, another less than 50,000 miles, and the third one at 35,000 miles. The 35,000 mile water pump was a catastrophic failure that damaged the radiator, clutch fan, and the wiring harness to the clutch fan.

I chose to purchase the Gates water pump because the pump is so easy (and inexpensive) to replace that I felt it was worth the risk of an early failure. But, the early failure never happened.

- John

 

[Rowdy Dalton]

When I say "Rubber Gasket", I really meant " O-Ring".

 

[Topzide]

HF sell a nice pressure tester that won't break the bank! Help me on several vehicles including my 3500. Had a hose that would weep after start up and stop when things were good and warm! Beat my head looking for it. One day after not using truck the prior day, put tester on and found one clamp not fully seated after replacing hoses with turbo actuator. Was loosing much coolant, just aggravating! Anything that has an o-ring seal must be double checked and checked again that an o-ring isn't left in place before replacement part installed! Jiffy Lube learned this the hard way back in the day by double o-ringing oil filters and destroying some high dollar engines! We replaced 3 '86 Toyota Supra engines. $12K for each engine alone and 6 - 8 week wait to get one back than. Always allow plenty of time to complete the repair! That way, you'll not be tempted to take a short cut!

 

[GSP7]

My 2005 I just bought has a slight leak. I can see Moistier from the bottom of the water pump like the O ring is leaking. There is no moistier coming from the front of the pump bearing/seal area just the base at the block
Looks like a bad o ring to me .
My record ( previous owner kept all maintenece records) show the replaced the water pump at a few years ago.

 

[Rowdy Dalton]

My 2005 I just bought has a slight leak. I can see Moistier from the bottom of the water pump like the O ring is leaking. There is no moistier coming from the front of the pump bearing/seal area just the base at the block
Looks like a bad o ring to me .
My record ( previous owner kept all maintenece records) show the replaced the water pump at a few years ago.

Once I had noticed my slight leak, it was only a couple of days, of short drives, before it turned into a major leak. The issue is that the water leaks out of the block, and still show a lot of fluid in the radiator. Potential recipe for an overheated engine. You might not realize it, because of where the temp sensor is located.