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Water pump bypass hose

Tiny
HIDDEN1
  • MEMBER
  • 2001 DODGE DAKOTA
  • 3.9L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 190,000 MILES
That darn metal tube that goes into the new water pump, new Oring, is leaking.

I wanted to know if I could use the black RTV around the tube/Oring? I see it's a common issue with these trucks.

I removed as much water as I could and dried up the inlet hole and spread a thin bead of black RTV then a bead around the pipe with Oring and pushed it in. Hopefully, I got the majority of water in pump out, with a pump hose, but it could slowly creep up since the hole faces up. I can let it set up for 8 hours.

Is this a good method or is there a better way to seal it?
Thanks
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Wednesday, May 11th, 2022 AT 1:20 PM

11 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,645 POSTS
Hi,

The idea that the system is under pressure really is why sealant won't work. The O-ring is a tight fit.

What I have seen happen is the new O-ring gets damaged (small nick) and will leak.

Here is what to try: Remove the tube from the water pump. Make sure everything is clean and in good condition. I oftentimes take a scuff pad and clean where it is inserted. Also, make sure where the O-ring is positioned is also clean.

Next, take Vaseline and coat the O-ring and where it inserts. Gently and carefully install the tube and once it is in, install the mounting bolt so it can't be removed.

Let me know if that helps.

Take care,

Joe

See pic below.
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Wednesday, May 11th, 2022 AT 8:34 PM
Tiny
HIDDEN1
  • MEMBER
  • 107 POSTS
I saw at junkyard, every Dakota had RTV on them!

The new pump O-ring was flimsy compared to the new bypass hose O-ring, $31.00 for a little pipe!

I did try the O-ring that came w pump and it leaked, even a bigger one but couldn't get it in even with gasoline.

I put a layer of RTV on clean dry pump hole and around clean pipe with another new RTV.
And tad at top after inserting it, and bolting holder.
Will 15 hours be enough time before putting the water in and bleeding the system and adding fluid?

And can RTV gasket maker.
Work with water and heat?
Also, is that the weep hole there on pic at red arrow?
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Wednesday, May 11th, 2022 AT 9:00 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,645 POSTS
Hi,

Let me know how it works for you. As far as the RTV, they make many different types for different heat ranges and materials. You should be able to find one made for automotive cooling systems that would be good.

As far as the time needed to cure, that is based on the type used. Some require little time while others require 24 hours. It should indicate the cure time on the product.

You mentioned the weep hole and a red arrow. I'm not sure what picture you are looking at.

If you look through this link, you will see the weep hole on the water pump in the pic. I copied and circled it in the pic below.

https://www.2carpros.com/articles/symptoms-of-a-bad-water-pump

Note: The weep hole is positioned differently on different pumps.

Let me know if this helps or if you have other questions.

Take care,

Joe

See pic below.
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Thursday, May 12th, 2022 AT 7:09 PM
Tiny
HIDDEN1
  • MEMBER
  • 107 POSTS
Here's pic. It didn't load.
I let it sit 2 days dry with the black RTV. I will flush the system tomorrow.
Does that radiator flush chemical eat into the RTV black I used on pipe/O-ring?.

I'm going to watch it after start up and be sure no leaks.

Is that the weep hole at arrow on pic?
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Thursday, May 12th, 2022 AT 9:44 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,645 POSTS
Hi,

The weep hole is on the exterior of the pump. As far as the flush, you should be okay.

I attached below a water pump and highlighted the weep hole. I believe the one on your vehicle will be hidden behind the pulley. Also, the arrow in your pic allows coolant to reach and lubricate the bearing.

Let me know if you have other questions and the outcome. I'm interested in knowing if the RTV does the job.

Take care,

Joe

See pic below.
Image (Click to make bigger)
Thumb
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Friday, May 13th, 2022 AT 7:19 PM
Tiny
HIDDEN1
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Okay, I was wondering where to keep an eye out via weep hold. So that pic is on a dodge 3.9?

I did the flush and so far, its holding, no drive yet ([I'll let u know after a drive if that pipe holds up). I raised the front of truck and it's staying cool, but I keep seeing some bubbles at cap even after the thermostat opens and.40 min of burping
With my radiator cap above the height of engine, will that help as I'm driving to get rid of any tiny bubbles still in it?
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Friday, May 13th, 2022 AT 7:53 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

No, the system becomes pressurized, and it won't change how it bleeds.

Don't be alarmed if you see a few bubbles. Also, make sure the heater is on high to bleed the heater core as well. If you have good heat, that tells me the system is circulating and likely there are no air pockets.

I will watch for your reply.

Joe
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Friday, May 13th, 2022 AT 8:19 PM
Tiny
HIDDEN1
  • MEMBER
  • 107 POSTS
Yes, the heat has been on the entire time and no overheating. I ran the motor and got good hot air. Emptied radiator, recirculation water, 2 times and refilled with water then on last refill distilled water, then coolant.

45 minutes and thermostat opened up. Not a lot more bubbles but a few every now and then.
Do some bubbles you don't get out leave through overflow tube eventually.

Not sure I can get 100% out.
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Friday, May 13th, 2022 AT 10:36 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

If you are seeing very little, it is fine. Put the cap on the radiator and just keep an eye on the coolant reservoir for a day or two. What you are seeing now is normal.

Let me know how things turn out.

Take care,

Joe
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Friday, May 13th, 2022 AT 11:01 PM
Tiny
HIDDEN1
  • MEMBER
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Thanks, took it about 40 miles on stop and go traffic and no leak that I can tell. Once back home I will put cardboard under it and see. I wish I would have used that RTV made for water pumps though.
Thanks!
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Saturday, May 14th, 2022 AT 10:52 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

It sounds like you fixed it. If it didn't leak under those conditions, I feel confident it will be fine. If things change, let me know.

Please feel free to come back anytime in the future if you have questions.

Take care,

Joe
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Saturday, May 14th, 2022 AT 8:02 PM

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