Ideal drain plug metal for aluminum case

[MoreCowbell]

This question actually relates to a motorcycle but the question is universal: it's mechanical.

Consider that the choices here for the plug metal are SS and aluminum.
With an aluminum case, is SS absolutely ideal for the drain plug?

Can an aluminum plug be used just as well?

I ask this because I am entertaining adapting a brass oil temp. sender to a new drain plug as the easiest port to tap for temperature. If I could use an aluminum plug (with a Neodymium magnet), that would be easier to machine than SS. My concern is long germ viability of the thread mating with aluminum-on-aluminum.

 

[UG_Passat]

Just don't cross thread aluminum on aluminum

Stainless steel and aluminum can react due to galvanic corrosion.

 

[Number_35]

I was going to recommend using anti-seize, and then realized that you likely need the sensor to be grounded through the case.

Then realized I don't know whether anti-seize is conductive. Time to get out the multimeter.

 

[Astro14]

Nickel and copper antiseize purport to be conductive. I use a very thin swipe of nickel on sparkplugs. Reckon it can’t be too bad…

 

[oil pan 4]

An aluminum plug will try to round off.

 

[kschachn]

Nickel and copper antiseize purport to be conductive. I use a very thin swipe of nickel on sparkplugs. Reckon it can’t be too bad…

And it will still conduct through the thread-to-thread contact, that’s where it conducts anyway. It will work whether you use the anti-seize or not and whether it is conductive or not.

 

[paulo57509]

What material is the OEM drain plug made out of? Can you find a plug in that same material?

Commonly available anti-seize has to be conductive or there would be a lot of near-dead spark plug installations. I don't know when I discovered this but I use Champion 2612 anti-seize.

I don't know what kind of seal your OEM or proposed drain plug uses, but I'm assuming it's some kind of crush washer. I've always thought that the torque specs for the plug assumes a new washer. Typically, common torque specs are there to induce enough stress in the threads to keep things tight; in the case of drain plugs with crush washers, the torque spec is there to provide adequate crush to affect a seal.

 

[MoreCowbell]

All good responses and I really appreciate the quips. Many have opined about electrolysis. Others have rightly opined about the downside of aluminum-on-aluminum thread mating in terms of durability. To Paolo's question, the OEM plug (M15x1.5) is steel (not SS) with a magnetic core, and (I believe) uses a thin crush washer. Looking closer at the crank case, I believe I may have spotted a "spare" plug near the drain plug that I can exploit for a temp. probe. In rethinking this, and considering all the good comments here, I think I'd like to shy away from modifying the oil drain plug for this purpose. Next time I drain the oil, I plan to remove this other plug to see if it can be modified to accommodate the VDO sender. Cheers!

 

[xmanjeff]

alum on alum will gaull, i highly advise not to use alum