[79 Phoenix]

]I WANT TO HAVE BOTH IDIOT LIGHT AND MECHANICAL WATER TEMP GAUGE ON MY GT-37.

THE 400 ENGINE HAS AN ALLUMINUM EDELBROCK INTAKE. ON THE PASSENGER SIDE OF THE THERMOSTAT IS THE CURRENT WATER TEMP SENDER THAT NEEDS TO BE REPLACED. I'M CONFIDENT I CAN GET THAT OUT. ON THE DRIVER'S SIDE OF THERMOSTAT IS A STEEL PLUG THAT NEEDS TO COME OUT SO I CAN USE BOTH HOLES FOR THE 2 SENDERS. 3 QUESTIONS:

1) HOW BEST CAN I REMOVE THE STEEL PLUG WITHOUT DAMAGING THE ALLUMINUM MANIFOLD? LONGER BREAKER BAR? MORE HEAT? IMPACT GUN?

2) I WANT THE MECHANICAL WATER TEMP GAUGE TO BE THE GAUGE I PRIMARILY RELY ON FOR WATER TEMP. IS THERE A BETTER SIDE TO PUT THAT SENDER?

3) IS THERE AN ALTERNATE LOCATION BESIDES THE MANIFOLD TO PUT THE MECHANICAL SENDER?

[BILL BOWMAN1]

How long has the plug been in there? If it has been decades, I would be afraid it’s gonna take the aluminum with it.

[Sirrotica]

One person using steady pulling on the breaker bar, while another person heats the aluminum up. You need to keep moving the heat around the hole, while having a steady pull. Too much torque will round out the hex in the plug, then you're pretty much limited to drilling and chiseling it out.

Likely tere is some type of sealer on the plug threads, and heat will break the adhesion of the sealer, while expanding the outer threads. Galvanic corrosion between 2 dissimilar metals can also add to the seized threads.

I'd avoid using an impact, as those plugs are generally made out of really soft alloy, prone to stripping out the hex socket when hammered with an impact.

Having worked on this stuff for over 50 years, heat is your friend.

You also have the option of a Tee fitting to attach both senders to one hole.

[steve25]

Get a big flat nose punch that will just fit into the hex hole.
Give it some really good hits with a big ball peen hammer and you will jar the threads around in the Manifold and that pipe plug will come free.

[Tim Corcoran]

If you have an oxy acetylene torch put some penetrating oil around the plug then heat the metal plug not the manifold use a small tip as to direct the heat to the center of the plug, get it good and hot till it starts turning red then as it starts cool down put the wrench on it and it should come out without much effort. It could take a couple heating and cooling cycles.

[b-man]

Why the caps lock this time, plus the constant use of large type and bolding (which I’ve undone here) in all of your postings?

It’s annoying for those reading so please stop.

[i82much]

I've had luck alternating between a propane torch and that freezing penetrating oil stuff.

[burd]

Drill it out.
Get another intake, there’s tables of them at the swaps Sell that one.

[79 Phoenix]

Originally Posted by b-man

Why the caps lock this time, plus the constant use of large type and bolding (which I’ve undone here) in all of your postings?

It’s annoying for those reading so please stop.

Sorry, no reason for all caps...Didn't mean to be annoying...

[79 Phoenix]

Well, thanks everybody for your great input. After trying again with as much propane heat I could give it and breaker bar, it didn't budge. I decided to leave well enough alone. I can live with just the temp gauge and will seal up the harness plug for the light.

[b-man]

Originally Posted by 79 Phoenix

Sorry, no reason for all caps...Didn't mean to be annoying...

And the oversize bold type you’re using in everything you post, as I already mentioned in my previous post?

Please stop that, that’s not necessary either.

[Joe-Touring]

They aren’t easy to get out, probably been living there for a couple decades. The last one I removed I had to drill it out and use a giant EZ-Out. Once you drill out enough of the center it removes a lot of the tension on the threads

[blueghoast]

I've seen guy's use wax on blocks with heat to get into the threads
not sure how it would work on alluminium, might be worth a try?
Good luck with it.

GT

[burd]

I tried a diff font, it’s catchy

[burd]

lol

[Schurkey]

Originally Posted by i82much

I've had luck alternating between a propane torch

Acetylene or Propane plus Oxygen is much hotter, works WAY better.

As said--heat the plug, not the casting.

Originally Posted by i82much

and that freezing penetrating oil stuff.

Tried that once. Enormously too much oil along with the refrigerant. Messy as hell--slimes up everything. Better-off to just use a can of R134a and a squirt of two of penetrating oil.

Overall, I'd rather use heat than cold.

[b-man]

1972 and up cylinder heads have a provision for a temp sender in the side so you have another place for a sender besides the intake if running the later heads.

[steve25]

The side of the head location just happens to be the most accurate location also.