Heater Bypass Nipple Seized

[Dart50]

I recently bought a car with a 76 318 engine.
I pulled the front off the engine to do the timing chain and discovered why the bypass hose always leaked.

It looks like someone installed a gas fitting with threads the entire length. The hose never gets a seal on the threads. This thing is black iron and is a nasty rust mess. You can see from the stains in the picture it leaks a lot.

Now the problem….
I soaked the thing in home brew penetrating oil (acetone and transmission fluid) most of the day while I worked on other things. I used an internal pipe wrench and a two foot breaker bar to try and free it. The thing is not budging. The internal pipe tool is just expanding/ deforming the tube. Now there is no turning back.
I am afraid to hit it with heat because I figure it was going to ruin the intake manifold gasket. I would like to avoid pulling the intake if at all possible.

I would appreciate any help on this one.

Thanks.

 

[toolmanmike]

You may have to take the intake off and heat it. It looks pretty close to the end gaskets and silicone.

 

[RedFish]

best to take the thermostat out so you can see what the other end of a hacksaw blade is doing. Cut through the depth of solid pipe wall from inside out. The threaded part of the wall will then collapse with little effort.

 

[famous bob]

best to take the thermostat out so you can see what the other end of a hacksaw blade is doing. Cut through the depth of solid pipe wall from inside out. The threaded part of the wall will then collapse with little effort.

last post, be carefull. pipe tapp if you mess up a little bit. this is why you should always use brass nipples.

 

[jdsduster]

best to take the thermostat out so you can see what the other end of a hacksaw blade is doing. Cut through the depth of solid pipe wall from inside out. The threaded part of the wall will then collapse with little effort.

good luck,these can really be a pain in the butt.before you have cut all the way through you can roll it wth a chisle

 

[Frank Mopar]

I would put the internal pipe wrench in to keep it from collapsing and use a regular pipe wrench on the outside. A little heat wouldn't hurt. Good luck.

 

[krazykuda]

Try using a propane torch to heat it and then crank on it with a good pipe wrench...

 

[Dart50]

Thanks for all the suggestions….

I got it out but I thought I would share what happened...

• Tried combination of internal and external pipe wrench. Pulling on them both at the same time. Tones of torque applied to the fitting but nothing. Huge pipe wrench and a 2 foot breaker bar on the internal wrench. Not even the slightest budge.

• I decided to try heating with MAP gas. Did a couple of cycles and the same two wrenches above. Nothing.

• Tried melting wax into the threads while hot. No difference.

• The winner…

Decided to try cutting and collapsing the fitting (pictures included).
I used a Dremel to cut two slots in the pipe right up to the manifold. Then I did a cross cut to leave a ½ slot down the pipe. The used a hacksaw blade to very gently cut the section of pipe inside the manifold.

I collapsed the pipe with a pair of vise grips. The thing was still holding on even after I collapsed the pipe. I broke out a chisel and started just rolling the tube more and more to if finally came loose. The thing held on to the bitter end. There was less than ¼ of the pipe surface left touching before it broke free.

Why was it such a pain? When I finally got it out it looks like the threads were a sketchy and the guy used something like JB weld in there and then jammed in a pipe fitting.
So much for not taking off the manifold, Heli-coil or new manifold it is…

Thanks to all for the suggestions.

 

[RedFish]

Maybe the same size tapered pipe tap would correct the threads being run deeper on the taper.
Otherwise,Should be able to rethread it where it sits to next size up. Then a brass or even aluminum fitting.

 

[Dart50]

I finally got back to the car.

A friend had a ¾ pipe tap. I tapped the hole with the manifold in place but had to go deeper than usual would with a pipe tap in order to get into good metal.
I installed a brass ¾ NPT to barb fitting but it screws in almost all the way due to the hole being a little oversize now. I put on some high temp thread seal and tightened in the fitting. I hope this works.
Now on to the next problem…..

Thanks to all for your suggestions.