Aluminum Intake Manifold Plug Stuck

[Cathy S.]

Any suggestions on how to remove a plug in my aluminum intake without harming the intake?

[Tom P.]

Re: Aluminum Intake Manifold Plug Stuck

What kind of manifold (year SB, BB/)? What kind of plug (hex head, square head)? Is the manifold on or off the engine?
Just a tiny bit more information would help.

[Cathy S.]

Re: Aluminum Intake Manifold Plug Stuck

Small block 1966 manifold that someone put a square head plug in the heater hose hole. The manifold in on the engine

[Patrick N.]

Re: Aluminum Intake Manifold Plug Stuck

Could be a case of galvanic corrosion if the plug is steel. The two metals with the coolant will oxidize causing the aluminum to deposit on the steel creating a solid bond. I had a similar situation when my manifold was off the car. With the manifold off the car, I heated the area with a mapp gas BenzOmatic (I would NOT use heat if the manifold is on the car) and soaked with Kroil, let cool, more heat, more kroil. It was not easy but it did eventually free. The aluminum must be completely cool before trying to remove the plug- the aluminum will expand tighter on the threads. It's a tricky job, I would be careful to not over power the plug when trying to persuade it to come off which may damage the to manifold. This worked for me, but others may offer an even better approach as well to consider.

Patrick