Heating Aluminum Case to Remove Oil Plug

[fidowanttobe]

Seized steel drain plug in an aluminum transmission case.
Before I strip it out to the point of welding something to the plug, (its a 17 MM Allen head) I want to heat the case with my acetylene only torch.
It still has oil in it, a GM Synchromesh which looks like a 10/30 type.
Tell me what I need to know please.
Not a newbie but first time for oil filled aluminum for me and I'm nervous. Can acetylene only, (plumbers torch) melt aluminum? Fire?
Or am I stressing over nothing as it would take a loooong time heating for either to happen?
Thanks in advance.

 

[fried1765]

Seized steel drain plug in an aluminum transmission case.
Before I strip it out to the point of welding something to the plug, (its a 17 MM Allen head) I want to heat the case with my acetylene only torch.
It still has oil in it, a GM Synchromesh which looks like a 10/30
Tell me what I need to know please.
Not a newbie but first time for oil filled aluminum for me and I'm nervous. Can acetylene only, (plumbers torch) melt aluminum? Fire?
Or am I stressing over nothing as it would take a loooong time heating for either to happen?
Thanks in advance.

Acetylene gas alone, burns with a flame temperature of approximately 2200 degrees Celsius (4000 F).
Aluminum melts at 660 degrees Celsius (1220 F)
You make the call!

 

[fidowanttobe]

Thanks. Exactly the type of info I needed.

 

[5030]

Had the same issue with the front diff on my wife's Suburban, steel plug seized in the aluminum case. Took my MIG and welded on a hex nut and ran it out. The MIG gave it enough heat to come loose. I also welded on another hex nut to the NEW plug I purchased to replace the old one I removed. Not a good design, typical GM I put some never seize on the threads too.

The replacement plug and the OEM one were / are cast steel with a cast in hex on the end that is basically worthless.

 

[5030]

I use heat all the time on stubborn to remove fasteners. Usually my propane torch.

Keep in mind that die cast aluminum isn't pure aluminum, it's mostly recycled stuff so the melting point can be higher and usually is.

 

[crazyal]

With the oil still in it (unless you flip the truck over) will resist heating the aluminum. It's like trying to solder on a copper pipe with water in it. Granted you are not going to need to get to soldering temperatures but it'll still have an impact. Also if the oil get too hot (much lower than the aluminum will melt) it'll start to burn. It would be messy but you could drill a hole in the center of the drain bolt. I think I would try a 17"mm wrench on the allen wrench as close as possible to the drain bolt to eliminate as much as possible flexing of the allen wrench and see if that helps.

 

[PILOON]

Unlike steel that gets red B4 melting, aluminum shows no color change and simply ---melts.
So be very careful.
That said heat (moderate) might help to break the bond, for sure it will draw some oil into the threads making it easier..
Just concentrate heat on that steel plug.

 

[WranglerX]

IF you can get it hot enough you can not touch it, its going to be hot enough to release, you only need to raise temp a few hundred degrees, and I would bet you can not get it hot enough with propane torch or acetylene (Prest-o-lite) torch to melt it unless you have along time to apply heat....

If you have welder, put big nut on it and burn it on then remove plug/nut while still hot....

Anti seize Lubricant is your friend....

 

[5030]

IF you can get it hot enough you can not touch it, its going to be hot enough to release, you only need to raise temp a few hundred degrees, and I would bet you can not get it hot enough with propane torch or acetylene (Prest-o-lite) torch to melt it unless you have along time to apply heat....

If you have welder, put big nut on it and burn it on then remove plug/nut while still hot....

Exactly what I did with the Suburban

 

[jonsstihl]

I would use an electric heat gun. the kind used to strip paint. actually you want to heat the aluminum and cool the plug. but the oil in the pan will resist both. aluminum expands more than steel for the same temp.

I would heat the pan around the plug for a few seconds/minutes then touch the plug with an ice cube just before untorquing.