95 Cobra R Lower Radiator Hose Petcock leaking

[SLOWBRA]

After 26yrs the lower radiator hose petcock decided to call it quits by leaking coolant.

After a two unsuccessful attempts to re-install the petcock (1st with new teflon tape and then permatex teflon thread sealant with PTFE) I decided to get a new petcock. Unfortunately, the new petcock is leaking worse then before.

It seems that despite using ample teflon sealant, tightening it well, and letting it dry for three days, that I can't get a good seal for it to stop the leak. The petcock did not leak when originally filled with fluid and when the car was cold/unpressurized. It started leaking after the car warmed up and pressurized. The leak is coming from the threaded portion of the petcock that screws into the lower radiator hose coupler (see pics showing leak coming from the threads sealed with teflon).

I've inspected the coupler and it's threads a number of times and don't see any reason for it to leak. I don't see evidence of a crack or anything either. However, my guess is there has to be one inside the threads that I cannot see?

Wondering if other 95 R owners have gone through this and have advice. I've done the obvious and this little annoyance has me stumped.

 

[brianz426]

Maybe someone could reproduce these with a 3-D printer? I would buy one for a spare.

 

[specracer]

Maybe take the piece to a good radiator shop that can pressure test it, and ID the leak?

 

[Cobra Jet]

This may be a long shot but try this:

Remove the petcock, throughly clean all of the inner and outer threads of the Teflon goo. Make sure both inner and outer threads are dry and free of any debris.

Grab a can of “The Right Stuff” gray gasket sealant. Apply to inner and outer threads, reinstall petcock and let sit to thoroughly dry before introducing coolant again. The product should stop the leak.

Permatex® The Right Stuff® Grey 1 Minute Gasket Maker, 3 OZ - Permatex

www.permatex.com

I’ve used the product many times for various seepages/leaks and it’s by far the best sealant product out there for engine related fluid seepages/leaks or reassembly of parts that come in contact with fuel, oil or coolant.

Post your results if you give it a go.

 

[CobraBob]

That does sound like the easiest and least expensive potential solution. I would definitely try The Right Stuff following @Cobra Jet's directions and give it a shot. The fact that you're using the sealant on both the inside and outside threads is reason enough to be hopeful. Let us know how it works if you try it.

 

[tomshep]

I think the above advice is as good as you will get.

This fitting is one of those items on the 95s that concerns me about wearing out due to the caustic environment of the coolant. I haven't been able to find anyone that knows the source or provider of this part.

It has to be adapted from another source, whether Ford or some other vehicle brand.

I'd also be very interested in figuring this out an getting spares.

Tom

 

[specracer]

Well on the bright side, this part should be relatively easy to replicate, vs other exclusive parts, like the plastic degas bottle for example.

 

[SLOWBRA]

This may be a long shot but try this:

Remove the petcock, throughly clean all of the inner and outer threads of the Teflon goo. Make sure both inner and outer threads are dry and free of any debris.

Grab a can of “The Right Stuff” gray gasket sealant. Apply to inner and outer threads, reinstall petcock and let sit to thoroughly dry before introducing coolant again. The product should stop the leak.

Permatex® The Right Stuff® Grey 1 Minute Gasket Maker, 3 OZ - Permatex

www.permatex.com

I’ve used the product many times for various seepages/leaks and it’s by far the best sealant product out there for engine related fluid seepages/leaks or reassembly of parts that come in contact with fuel, oil or coolant.

Post your results if you give it a go.

Do you know how this gasket maker compares to the Motorcraft TA-31? I’ve used that motorcraft stuff in a variety of different applications with success, but never to help with a crack.

I am certainly willing to give it the gasket maker a shot. Do you expect the gasket maker will provide a seal even if thee is a crack that presents itself when warm/pressurized?

 

[specracer]

If you really have a crack, I would want to find it, and come up with a real fix, like TIG welding it. Again a radiator shop will be able to pressure test the piece.

 

[Cobra Jet]

Do you know how this gasket maker compares to the Motorcraft TA-31? I’ve used that motorcraft stuff in a variety of different applications with success, but never to help with a crack.

I am certainly willing to give it the gasket maker a shot. Do you expect the gasket maker will provide a seal even if thee is a crack that presents itself when warm/pressurized?

Based on your posts and images, it appears the seepage is coming from the threaded insert of the “T” where you have inserted the drain **** valve. If liquid Teflon is not sealing those threads, coolant will seep past the threads. Teflon tape may work better, but you will have to do multiple layers and even then, there’s no guarantee the coolant would not seep past the Teflon tape. The Right Stuff should seal that problematic area only if you apply it as I posted above for you. The Right Stuff would exceed the properties and function of the Ford Motorcraft sealant.

IF the leak is not coming from within and past the threads in the T, then you have to look for a fracture on the T-fitting itself. As was suggested a radiator shop may be able to pressurize that part and find any cracks in it. If the T is cracked, you could use a number of products that will seal cracks in plastic piping. One such product I can think of is the black ABS pipe glue found in Lowes or Home Depot. You would have to know where the crack is on the T, apply the glue over it, let it thoroughly dry and apply a 2nd coat again and let it dry. The ABS glue will dry rock hard and be just as strong as the pipe (T) itself.

Replacing the drain **** valve is one thing, or sealing it with The Right Stuff. However it’s a completely different issue IF that plastic T has a fracture in it, and is seeping over the drain **** valve - giving the appearance that the leak is coolant seeping past the threads from the inside out. Hard to tell from your images.

 

[SLOWBRA]

I get your suggestion better now and thanks for the note on the quality of the right stuff - I’ve heard great things.

It’s worth noting that none of what is shown is plastic though. It’s all metal. I don’t see any cracks in the threaded portion where the petcock goes whatsoever so I do think that the issue is that the Teflon tape and Teflon thread sealant is not doing the job.

I’ll take it back apart in the next day or so and do one more thorough inspections before trying your suggestion.


Sent from my iPhone using svtperformance.com

 

[tomshep]

Can you find any markings on that piece? I'd love to try and figure out who originally made it. For some reason, it seems like something used on a tractor or industrial engine. I'm sure its off the shelf for some application.

Can you get photos from all angles and an end shot and post them?

Tom

 

[SLOWBRA]

Can you find any markings on that piece? I'd love to try and figure out who originally made it. For some reason, it seems like something used on a tractor or industrial engine. I'm sure its off the shelf for some application.

Can you get photos from all angles and an end shot and post them?

Tom

I would love to find that out too. Happy to send some pics when I take it off again.

 

[Cobra Jet]

Ohhhh… didn’t realize that T is metal! When looking at your pics several times, it sure does look like plastic!

I would be interested too in more pics of it and any identifying marks. Knowing how Ford used many “bin” parts that were already around for other production vehicles, I would not doubt that part was from another product line…. Maybe the truck line of the time?