Prepping aluminum to aluminum and to steel fittings

[JHZR2]

Got this Chinese aluminum radiator. Only option in the world for my 1991 350sd.

Quality is poor. But it’s the better if two or three Chinese options.

For example, look at the difference in the AT cooler:

OE

Chinese

The drain plug is in the OE location, but it’s not the OE type or thread pitch.

The drain Allen bolt is aluminum into aluminum. The AT cooler connections are steel onto aluminum. I’m concerned about all of them corroding shut and being unrepairable. Then this unobtanium radiator will have to be bought again.


Dare I wrap all connections with Teflon tape? I’m not sure I want Teflon in my AT cooler, but I also don’t want antiseize particles or a seizes cooler hose.

Any suggestions on how to prep these connections?

Thanks!

 

[George7941]

You really have not asked your question. Are you threading a steel fitting into an aluminium fitting and concerned about galvanic corrosion, or something similar?

 

[JHZR2]

You really have not asked your question. Are you threading a steel fitting into an aluminium fitting and concerned about galvanic corrosion, or something similar?

The question is at the bottom - suggestions on how to prep these connections…

One is an aluminum plug in aluminum, the other is a steel AT cooler hose fitting on aluminum (OE was brass).

 

[michaelluscher]

Would a PTFE thread sealant or a copper anti seize insulate

 

[RooflessVW]

I would use thread tape without hesitation

 

[Ihatetochangeoil]

To prevent galvanic corrosion between the steel/aluminum, I would spray the steel with cold zinc galvanizing spray paint. As a backup, I would not hesitate to use a non-hardening thread sealer such as Hylomar.

"Galvanic corrosion can be prevented by taking a few simple steps when working with dissimilar metals. Cleaning all surfaces before bringing them into contact with each other will help reduce risk; furthermore, using insulating materials (like rubber gaskets) and sacrificial barriers (like zinc coatings) will also help protect against potential damage caused by galvanic corrosion over time. Following these tips will ensure that your steel and aluminum components remain safe from corrosion long into the future!"

How to Prevent Galvanic Corrosion Between Aluminum and Stainless Steel ?

Galvanic corrosion occurs when two different types of metal are in contact with each other in an electrolyte solution, such as salt water or damp air.

blog.thepipingmart.com

 

[97K15004WD]

I would use thread tape without hesitation

Yep, same here. Just did the same thing with a steel plug into an aluminum case on a Nissan manual transmission.

I would not use a sacrificial coating as it might lead to binding, because it's sacrificial and will corrode (this is only preventing the base metals from corroding).

 

[George7941]

I would use pipe joint compound, it fills gaps better than tape. Once it sets up, it keeps out liquids from the threads and thus prevent galvanic corrosion. Loctite 567 is what I use, it sets up slightly, like a mild threadlocker.

 

[Cujet]

I've tried Loctite, JB Weld, C5 anti seize, nickel anti seize and just about everything else I can get my hands on. The bottom line is this, stainless on properly anodized aerospace aluminum (AN fitttings) works well without anything, at least once. But liberal use of Teflon tape is the main way I've been able to reliably disassemble annoying combinations. It may not prevent metal to metal contact, but it prevents 100% of the 2 surfaces from fusing together.

The other product that works quite well is this:

https://www.amazon.com/567-Thread-Sealant-50-Tube/dp/B01N9ZH553/ref=asc_df_B01N9ZH553/?tag=hyprod-20&linkCode=df0&hvadid=222720245886&hvpos=&hvnetw=g&hvrand=17969608419815005763&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9012045&hvtargid=pla-382944607366&th=1

 

[Tow motor]

Blue Monster makes teflon tape with nickel in it for anti seize properties. It is called nickel guard tape. Stainless and aluminum are both on the approved materials list.