I'm a moron and I over tightened the coolant temperature gauge sensor until it broke off of the head. Now, there's basically just threads inside the head. I've attached pictures:






The hole seems sealed so I suppose I could run the motor without the sensor but I'd like to be able to monitor my coolant temp.

What can I do to get this sensor out of the head?

 

I'm at a loss...I'm thinking of using a heat gun to heat up the area and hopefully the sensor will come loose.

I assumed the sensor was made out of brass and looked up the coefficient of thermal expansion for it and compared it to aluminum (the head) and the aluminum will expand more than the brass sensor.

Does this sound like a good idea?

 

Do not heat the head!!. They make a tool called "EASY OUTS " they prettymuc thread in backwards so you can remove things like this. I'd go get a set of those and start with that. If you have a steady hand use a small chisel and hammer if worse comes to worse. But its hard to tell how much material you have to work with from the picture. Once you get it lose it should back right out no problem, provided it was not stripped going in and you forced it causing it to break vs over tightening it

 

That sucks man. If you cant get it out your going to need to take the head to a machine shop.

Thats a big effort.

If you cant get it to thread out, than I would cover it with JBweld, and find another hole to tap into for that sensor.

 

I already tried using a punch, but after I took the pictures. I should have said that. The punch just sheared the excess pieces off.

I was using a #5 extractor (not sure if the sizes are standardized) and it just got really tight without moving the sensor. It got to the point that I was a little worried about cracking the head. So I put on a #4 extractor but that was too small to catch enough of the sensor.

 

I'm not sure I'd recommend it in your particular case but you can take a small flat file and grind the edges to a realtively sharp edge so it looks like a parallelogram in cross section (see pic for reference). Use a small hammer to drive it into the hole and use a cressent wrench to try and extract it.



As a last resort you can drill out the remnants of the sensor and use a nail/punch ground to a point to collapse the remaining threads into the hole.

 

An easy out may not be the best choice for a couple reasons.
1) in order for it to bite, it will expand the diameter of an already locked thread.
2) If you break an easy out, you cannot drill them.

I would suggest using a dremmel and a small burr.