Coolant Bottle

This looks promising: https://www.proimporttuners.com/parts/toyota/mr2-spyder-weapon-r-aluminum-coolant-tank.html

Never seen this product before and not endorsing it, just found it with a quick google search.

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Now, I admittedly have never looked too close at the coolant overflow reservoir. However, these don't seem very complicated to the point where I'd feel comfortable making one with a thick plastic bottle in a mcgyver situation haha. Looks like the only "technical" part is the cap and what pressure it blows off at. I think the main thing would just be having the coolant reservoir and the inlets/ outlets at their same current height relative to the rest of the car because it matters when doing a coolant air bleed with the hanging hoses in the frunk. 

@ria  I don't know if the WeaponR tank will work because I can't tell if it comes with or is compatible with a pressure cap.  This looks like a sealed cap.  

You can use one of the Canton tanks or the Moroso (made by Canton).  I did a write-up of my installation on Spyderchat (under Performance, Kswap).  I chose the Allstar Performance ALL36116 tank.  The tank you choose should be 1 quart capacity or larger and take a pressure cap.  You need a 3/8 inlet hose barb (on the top) and a 3/8 outlet on the bottom of the tank.  Do not use brass fittings.  I am using an 18 psi cap from a Chevy.

Dave

I'm 100% satisfied with the Toyota coolant overflow tank. If it ever leaks Im going to pick up a used low millage for $40 one or just pay though the nose for a new one. I like that I can see the level easily  and it will mount in the exact position so I don't have to worry about any kind of introduction of air issues. This is certainly not something I want to jinks.

 Im actually amazed that my original is going strong. On BMWs and other European cars  they are known to crack.  

@dblotii

So what happens when you use brass fitting ?  I used one on my 2ar swap and it appears nothing is happening .

@phats Modern coolant has a very different anti-corrosion package (Organic Acid Technology) compared to the old green stuff.  It lasts 10 years in service as long as there is no copper or copper alloys (like brass) are in contact with the coolant.  You will not find brass radiators in production cars any longer.  I believe the presence of copper in the system depletes the anti-corrosion package.

Posted by: @dblotii

You can use one of the Canton tanks or the Moroso (made by Canton).  I did a write-up of my installation on Spyderchat (under Performance, Kswap).  I chose the Allstar Performance ALL36116 tank.  The tank you choose should be 1 quart capacity or larger and take a pressure cap.  You need a 3/8 inlet hose barb (on the top) and a 3/8 outlet on the bottom of the tank.  Do not use brass fittings.  I am using an 18 psi cap from a Chevy.

 

Dave

For the Canton, part#80-202 would work well.

The Canton and Allstar bottles look interesting. My bottle has yellowed, but looks solid and works fine. I see the top mount looks like it has the beginning of a crack, but not into the bottle portion, just the actual mount. I'll have to find a good compatible epoxy. Like Dev stated, I like the clear aspect of OE, but admittedly the aluminum looks sharp. Brass, copper and lead will break down over time when using the pink HOAT coolant. I believe that the red OAT is acceptable. Green works fine but it's not as protective. Or such is my understanding. 

I didn't think the coolant reservoir deteriorated?  The weapon R thing looks cool.  But I kind of like how the stock one just works and mounts easily.

Stock one will crack with time.

Posted by: @dblotii

@ria  I don't know if the WeaponR tank will work because I can't tell if it comes with or is compatible with a pressure cap.  This looks like a sealed cap.  

Another thing is I'm not sure if it has the right connections in the right places.  There should be a barb on the bottom and one on the top.  I personally wouldn't go with it and instead use the Allstar or Canton tank.