Weird Question: Can an oil tank be used for a radiator expansion tank?

[rennch]

Hi all.

For those of you following my blasphemy build, I've put a water cooled engine in my 69 911. I need to fabricate a coolant overflow/fill tank, but then I got the harebrained idea of using an old oil tank I have sitting around. Other than the cleaning and the fabrication part, is there anything I should be concerned about regarding the internals of the tank? I read it was copper plated in there, so should I worry about some sort of reaction to radiator fluid? It would be a trick, elegant solution if I could pull it off.

[EC900]

Going for that moonshine distillery look, polished up brass fittings and add some curly looped copper lines too!
My 2¢… Copper/brass composition alloys were the stuff old radiators were made of, so corrosion reaction isn’t going to be an issue nor would any well soldered connections even if under any pressurization.
Can’t wait to see this mod!

[rennch]

Originally Posted by EC900

Going for that moonshine distillery look, polished up brass fittings and add some curly looped copper lines too!
My 2¢… Copper/brass composition alloys were the stuff old radiators were made of, so corrosion reaction isn’t going to be an issue nor would any well soldered connections even if under any pressurization.
Can’t wait to see this mod!

That kind of data is what I was hoping for.

Any idea if you can weld on a tank, or does everything need to be brazed?

[john walker's workshop]

They're steel ya know.

[rennch]

I know, but I wasn’t sure if there was anything weird with the copper plating that I should be concerned about.


Sent from my iPhone using Tapatalk

[jmd88]

Hey Rennch,
For your pitted out oil tank, you could either cut that bottom section off, and rebuild (welding new material to old with a "squared out bottom section") or you could "braze fill" all the holes - much more intensive from the labor perspective and you're always gonna be worried about blow through under pressure.

I'd just chop out the perforated material and rebuild it. You've done so much custom work already, this should be a cinch. should be a non-issue only having a partially copper coated bottom.

loving the progress!

[E Sully]

Can you post a picture of the oil tank? If you have the original 69-71 oil tank in decent shape it is worth a few hundred to those restoring their cars.

[EC900]

Never thought to put a magnet to it….Sure looked like copper !
Now comes the question how long will a steel tank hold up to coolant…very likely with some concern with perhaps more electrolysis occurring over time. Catastrophic failure…probably not.
The novel idea of using the oil tank as an overflow reservoir may become less appealing. Even with some crafty brazing, plugging, the look may not be worth the work, reliability or functionality.
Split the old tank, have it re-plated copper, line it with a custom plastic bladder, run the lines, rivet it up like a clamshell, bingo.

[targa72e]

Steel is used in automotive cooling systems all the time, so I would not be worried about corrosion. I do think the pressure could be an issue. Stock oil tank has no pressure on it and typical cooling system needs to withstand 14PSI of pressure. The tank might not be able to withstand that much pressure repeatedly.

john

[rennch]

Oil tank guts.

A LOT of cleaning later…

I cut that big chunk out because there’s rust and I need to weld in a new panel. I’d also be curious to know if you guys suggest a particular set of inputs and outputs on this. I’m not exactly sure what to do.






Sent from my iPhone using Tapatalk

[rennch]

Progress.






Sent from my iPhone using Tapatalk

[M5guy]

https://www.summitracing.com/search?SortBy=BestKeywordMatch&keyword=summit+coolant+overflow+tank&cm_mmc=ppc-google-_-search-_-general-terms-_-keyword&gclid=Cj0KCQjw166aBhDEARIsAMEyZh6ARuiQjoDsKBmYrAUC GJ4U6XSGXQJGBto5QwASx2oZXNURE97K5ToaAhAvEALw_wcB


I would just use one of these. No work, no worries, inexpensive, look good.

[phelix]

Is the oil tank up to the job of being pressurised without distorting? Or worse?