Slight water leak at head gasket below water pump
 

Need recommendation for a good stop-leak product. Here are the details:

I've been working on getting a '30 Coupe (not mine) in running condition again after sitting for roughly 40 years outdoors.:eek: I have it running and driving and the engine sounds remarkably good. After running for an extended period of time, a slight coolant leak has developed just below the newly replaced water pump at the gasket line. Looking at it a little closer, I noticed both of the nuts holding the water outlet on the head were not tight to spec compared with the other head nuts. I tightened both up and the leak has slowed considerably, but seeps a little more when the engine cools down. Since the car has been out in the weather for so long and head nuts are VERY rusty I don't want to run the risk of breaking a stud by replacing the head gasket...

So I'm wanting to try a good quality stop-leak, if there is such a thing to see if it will stop the leak without removing the head. What would the experts here on the Barn recommend?

Re: Slight water leak at head gasket below water pump
 

Bar’s Leak.

I think it should solve your problem.

Re: Slight water leak at head gasket below water pump
 

I have used K-Seal with good results.

Re: Slight water leak at head gasket below water pump
 

those 2 bolts that hold down the water neck can crack the ears on the neck when tightened down. be careful. they may have been left a bit loose so as to not damage that neck.
if sealant does not work you could remove the neck clean the maiting surfaces and put it back on with just a good gasket maker/sealer.
but if the leak is at the head gasket and the sealer does not work then it may involve a new head gasket. i would try to avoid that if it is running good and the leak is not too bad

Re: Slight water leak at head gasket below water pump
 

Thanks for the recommendations. Stop leak is definitely worth a try in this situation.

Re: Slight water leak at head gasket below water pump
 

i think so too. it may not stop the leak instantly so dump it in and drive it lots to get that stuff circulating.
let it drip, water is cheap

Re: Slight water leak at head gasket below water pump
 

Worth noting that Bar's Leaks has several similar products. I assume you want the one specifically for head gaskets.

Re: Slight water leak at head gasket below water pump
 

Well, this question is about like asking which new pickup truck is better, -a Ford or a Chevrolet. :D

I typically use a product made by Irontite that is a ceramic sealer since I am sealing Head Stud threads or Gaskets -and not the Radiator. (I typically think of Bars Leak as a Radiator stopper-upper since it has ground-up copper particles)


IMO, the issue you want to make sure you do first is get all of the organic stuff out of the cooling system (oil, water pump lubes, antifreeze, etc.) where the sealer can actually seal. Since we are using the sealer on fresh rebuilds that has clean water jackets, ours is more of a surefire thing.

Likely most of the parts stores with have those K-Seal, or Blue Devil, or whatever Head Gasket Sealer meant for sealing cracked cylinder heads and blown head gaskets, so any of them is probably going to successfully do what you need. I would start by draining any coolant and then add Dawn dishwashing liquid to water and run the engine to circulate the soap so it will breakdown any greases or oils. Most of those Head Gasket wonder products likely have a flush they recommend that I would use to follow up the soap flush with. When you get ready to add the sealer, I would take a small piece of fuel line that you can slip over the radiator overflow tube. Stick a bolt in the opposite end of the hose to basically plug air escaping out the tube. What this will do is add pressure to the system (2-3 lbs) which will help force the sealer into the seeping area. Once you have run the engine for awhile (we typically run them for about an hour on our run-in stand after retorquing the head gasket). At that point, drain the coolant with sealer and then thoroughly flush the Radiator separately to get any remaining sealer out of the tubes so it won't plug the tubes. Then let the block sealer dry overnight, and you will be good. I'm sure there are other ways too, but this has worked well for us.

Re: Slight water leak at head gasket below water pump
 

Yes, I'm thinking I should go with the copper based formula instead of aluminum. The engine hasn't been opened in many years according to the owner, so I can't really tell if they used a copper or composite head gasket, but the copper formula seems to make the most sense. What say you?

Re: Slight water leak at head gasket below water pump
 

I was interested in Brent's description of Bars Leaks. The Bars Leaks we get has no copper in it - only chicken $#!T in soluble oil. Dried chook poop is a popular garden fertiliser here and swells when it get wet but not in oil. Once added to the cooling system, it circulates and lodges in the leak and swell to stop it. That product has been available unchanged for many decades
Back to the question at hand: I think any stop leak product is well worth a try.

Re: Slight water leak at head gasket below water pump
 

Thanks Synchro; appreciate your perspective on the issue.

Re: Slight water leak at head gasket below water pump
 

Thanks Brent,
Sounds like a very well thought out approach to correcting the problem. I'll give it a go.

Re: Slight water leak at head gasket below water pump
 

I think that's a good idea, pushing the sealer into the minute cracks.

Re: Slight water leak at head gasket below water pump
 

When you guys do a flush, are you running a hose into the top of the radiator, or do you do something different?

Re: Slight water leak at head gasket below water pump
 

Depends... If the hoses have been removed, then plug the side inlet with your hand or a rag and fill thru the outlet until it is full. Then 'unstop' the water inlet and it will quickly drain. Fill it again and then unstop it again. Then as they say, 'rinse & repeat' until it is flowing clear water.

Some of those Sealers are designed to have a Flush circulated by the Water Pump. A Model-A system partially works off of thermosyphon, so run the engine enough to circulate the cleaner. That is why we preface those flushes by using Dawn dish soap & water first.

Re: Slight water leak at head gasket below water pump
 

I honestly don't know if it has Copper in it. I've just seen it on the shelf at the auto parts store where it has Copper printed on the bottle. Maybe they are referring to the color?? :D

https://barsleaks.com/product/block-seal-1109/

Re: Slight water leak at head gasket below water pump
 

MM Brent's approach is a good one. Do you think it could be the nuts holdin the water pump on. On my fresh engine I had a similar situation and discovered the lower nuts of the pump needed just a bit of a snug up and that stopped the weep. Did you put a bit of sealer on the water pump gasket or gasket only?

Re: Slight water leak at head gasket below water pump
 

" Barrs Stopleak" is the way to go for sure . Ideal to stop weeps . I have used it for many years with no issues .

John in weather was cancelled today Suffolk County England .

Re: Slight water leak at head gasket below water pump
 

TBob,
I didn't use any sealer on the water pump gasket. However, I did check all the pump bolts for tightness and they seem to be fine and I don't see any leaks coming from that area. The weep is coming from the outer edge of the head gasket directly under the pump. I'm pretty confident that the stop leak will take care of it.