Coolant recovery tank

[rmchrgr]

I need to get some sort of overflow tank for the cooling system on my Duster. These tanks get called all sort of things - coolant recovery, coolant expansion, catch can, puke tank, etc. I'm not 100% clear on what each style does. I also want to confirm how to set it up properly.

My preference is to get the type that siphons coolant back into the radiator when it cools. I don't want one that just collects coolant if/when it pukes from the radiator cap since then you have to drain the tank and dump it back in the radiator if/when the coolant level gets too low. That's like 1950's tech. I'm looking at this one. Little pricey, yes.

Most of these aftermarket tanks have inlet/outlet fittings at the top and bottom. As far as I understand it, if the one on the top is used, it has to be connected to a tube that goes to the bottom for the siphon process to work but none of them seem to come set up that way and I don't want to fabricate that either. Presumably, utilizing the outlet on the bottom allows coolant to be siphoned back into the radiator after it cools?

Also - if the bottom outlet on the tank is used, the tank requires a vented cap, correct? The one I linked comes with a vented cap so that assumption appears correct. I figure on using a standard 16 psi cap for the radiator. I know some of these tanks that are used to fill the system and require a pressurized cap but I don't want that style.

Please let me know if I have this correct. Trying not to overthink it but it seems easy to setup incorrectly.

Thanks for any input.

- Greg

 

[RustyRatRod]

A coolant recovery tank does what the name implies. It receives overflow from the radiator and then returns it when the system cools down. But for them to work like they should, they really need to be mounted above the water level in the radiator. Sometimes difficult to do in our older cars. An overflow tank is just that. It is made to catch anything that overflows from the radiator and has no means by which to return it.

 

[qkcuda]

I bought this one on Amazon. It was around $50. The inlet is at the bottom. There is a second smaller tube that sticks out at the bottom and runs inside up to about an inch from the top and acts as an overflow. If you have the correct rad cap it functions perfectly as a recovery system and pulls the coolant back into the rad. If you have more room than I had, a larger capacity would be nice.

 

[niceolddart]

All of the 74 Dusters I've owned had coolant recovery tanks from the factory. The caps just snapped in place. There was a hose that attached to the inside of the cap & ran down to the bottom of the tank. Any coolant in the tank would be drawn back into the radiator by itself when it cooled off. I had one, but I think I sold it.

 

[remytherat]

The whole thing depends on the style of radiator you have. Earlier radiators have a large top and are intended to be filled to just above the tubes. These don’t have an external tank because they shouldn’t puke anything at all unless they get way too hot. Only need a tank if you want to race. Later radiators with a small rectangular top must be used with a 70s factory style recovery tank to function properly.

 

[RustyRatRod]

About the "expansion tank". An expansion tank is a remote pressurized part of the cooling system ans has the radiator cap located there. Ford used that system a lot through the 60s. Like this.

 

[mopowers]

I run a recovery tank like the one qkcuda showed a picture of. I can't recall exactly which one it is, but it's similar to this one: https://www.amazon.com/PQY-Radiator-Overflow-Polished-Stainless/dp/B0816D7QWT/?tag=fabo03-20

You connect the hose to the nipple at the bottom and there's a second nipple/tube that runs to the top of the tank just like qkcuda explained. This is the vent/overflow. It's simple and works perfectly. They make a ton of different sizes too, so it should be easy to find one that fits where you want it.

 

[qkcuda]

Mine is the same except it comes with 3 different screw in hose barbs for the hose to the radiator.

 

[4spdragtop]

No experience, but like @niceolddart described it wouldn't need to be sealed if the hose/tube led to bottom of reservoir? Unless I'm missing something?

 

[qkcuda]

The tank is not sealed, the overflow tube acts as a vent, but it works. You need a modern rad cap with a rubber seal.

 

[rmchrgr]

After working as a tech I really should know this stuff! I have not thought about cooling systems for what seems like years. Regardless, I think I got this straight now. The ones that are 'sealed' are probably better described as pressurized remote fill tanks. They have to be installed above the rad. cap. to keep the radiator full. They have a pressurized cap because they are part of the cooling system. The remote tanks don't get filled to the top because the coolant needs to have room to expand like with a down flow radiator.

For all intents and purposes a basic recovery tank really just collects the expanded coolant. The fact that it can be recovered is kind of an added bonus over just letting it go on the ground. It's 'open' though because it's vented to atmosphere in some fashion.

My radiator is a Griffin universal cross flow radiator with side tanks so it gets filled up to the neck.

I forgot that I have one of these inexpensive recovery tanks already. It was one one of my vehicles at some point.
Hard to recall there was ever any coolant in the plastic tank.

And yeah, it looks chintzy but at the same time it would be hard to to justify spending $175 on a fabricated aluminum recovery tank. The nice thing about the fab. ones are the threaded bungs. I can unscrew the rad. cap nipple and install an NPT adapter to connect to -AN hose so it doesn't leak. If hardly any coolant ever comes out though I should probably do without more fancy stuff.

 

[Professor Fate]

'73-'76 A bodies had them.
They looked similar, but there were 2 different versions. The '73 had 2 rubber lines from the cap, 1 to the radiator, and a discharge line clipped to the side of the body.
'74-'76 had one line to the tank from the radiator, the overflow was a molded-in part of the body.
The mounting bracket was slightly different between the two, also.
They are interchangeable.
You will also need to use the later radiator cap for the system to function properly.
Some pics I pilfered from other threads:
'73:

'74 and up:

They retrofit just fine onto older cars/radiators as long as the correct radiator cap is used.
The only real mod you have to do on the early cars is drill a hole in the top of the passenger frame rail- 1/2" IIRC. This is to accommodate the small locating "finger" at the bottom of the tank.

You may or may not need to drill 2 small holes- 3/16" or so- in the upper radiator yoke for the 2 small bracket studs; some cars have them, some do not.
In this pic you can kinda see where I even able to mount one in my '66; the bracket holes were already there (don't know what they would have been for in '66, but they fit the bracket perfectly), I just had to drill the top of the frame rail. The horns got relocated to the driver's side (those holes were already there, too).

I've put these in my '66 (as mentioned), '68s, and a '70; so I know they fit and work all along the A body production run.

 

[tonysrt]

I have a 71 Cuda with the 26" radiator and room is so limited to fit any of the mopar overflow tanks. I actually used a Honda Civic tank because it was so small and does the job.

 

[rmchrgr]

Prof., thanks for all that but like I said in post #11 I'm going to stick with the smaller aftermarket one I already have.

Years ago when I first bought my Duster it had the tank seen in the lower right of the pic below. I might still have that thing somewhere but even if I did it wouldn't go back on the car.

 

[Bewy]

A recovery tank is a good idea. My engine ran a little cooler with one. They will work with any conventional radiator.

 

[Dana67Dart]

That's like 1950's tech

The radiator tank can have an inch of air above the coolant. It dies not need to be completely full. In all reality, you could fill the rad to the top, go through several heat cool cycles and the coolant will find its level in the radiator. Maybe in the hottest heat of the summer it will loose but more but after that it will probably not loose a drop again.

I'm on 7 years with no recovery tank. I drag raced my car several times on a hot summer day, I had to have a recovery tank per rules, at the end of it all, not a drop in the recovery tank. No over heating, no issues.

Having a tank is a personal decision.


On the subject of the type of tank .

If it's not vented it will pressurize above the pressure of the cap.

If it has a bottom tap and a vented cap your all set.

If it has a top tap the tap must have a hose to the bottom of the tank AND the tank MUST be vented.

placement... It can be lower than the coolant level in the radiator because if it starts to syphon the coolant out of the engine there will be a point where there is sufficient vacuum in the engine to stop it. UNLESS.. the cooling system has a leak.

 

[matthon]

I made an recovery out of an aluminum water bottle, one of the 758 in the kitchen cabinet, and some hard fuel line.

 

[Dana67Dart]

I made an recovery out of an aluminum water bottle

My dad made one out of an orange juice bottle, he had it on his / my dart since the late 70s when I got his car it was one of the first things I removed.

 

[Kendog 170]

'73-'76 A bodies had them.
They looked similar, but there were 2 different versions.

I have this one in my Hardtop. This type no hole in frame rail needed. Just installed the Frame hole type in my Ragtop this past fall. No pic of that one. As said big radiator you need smaller cylinder style.

 

[66fs]

'73-'76 A bodies had them.
They looked similar, but there were 2 different versions. The '73 had 2 rubber lines from the cap, 1 to the radiator, and a discharge line clipped to the side of the body.
'74-'76 had one line to the tank from the radiator, the overflow was a molded-in part of the body.
The mounting bracket was slightly different between the two, also.
They are interchangeable.
You will also need to use the later radiator cap for the system to function properly.
Some pics I pilfered from other threads:
'73:

'74 and up:

They retrofit just fine onto older cars/radiators as long as the correct radiator cap is used.
The only real mod you have to do on the early cars is drill a hole in the top of the passenger frame rail- 1/2" IIRC. This is to accommodate the small locating "finger" at the bottom of the tank.
You may or may not need to drill 2 small holes- 3/16" or so- in the upper radiator yoke for the 2 small bracket studs; some cars have them, some do not.
In this pic you can kinda see where I even able to mount one in my '66; the bracket holes were already there (don't know what they would have been for in '66, but they fit the bracket perfectly), I just had to drill the top of the frame rail. The horns got relocated to the driver's side (those holes were already there, too).

I've put these in my '66 (as mentioned), '68s, and a '70; so I know they fit and work all along the A body production run.

I used one on my 68 Barracuda. I used a plastic piece attached to the frame rail to hold the bottom "pin" and drilled 2 holes for the top studs. Worked like a charm.

 

[rmchrgr]

I'm on 7 years with no recovery tank. I drag raced my car several times on a hot summer day, I had to have a recovery tank per rules, at the end of it all, not a drop in the recovery tank. No over heating, no issues.

That's been my experience as well. Better safe than sorry though. I don't want to leave any coolant on the ground if I can help it.

If it has a bottom tap and a vented cap your all set.

This is the aftermarket one I forgot that I had. The reason I remembered I had it is because there are two holes next to the radiator where it used to be. As soon as I saw them a little voice said hey dummy go look on the shelf. The holes are too close to the radiator now though.

I'm gonna mount it here, just have to make a mounting bracket for it. I'm really not a fan of how it looks so I may end up with something better looking later on. You can see the previous mounting hole to the right. Going to make a "Z" bracket so I don't need to drill anymore holes.

This post reminded me of something that happened a few years ago with the coolant recovery tank my '68 Coronet. I had an aluminum cylinder type with the two pieces of tubing brazed into the bottom. It had a twist-on cap and I believe the hose was attached to the bottom. (May not have been though!)

One day while driving down the road the cap blew off of it and went into the woods. It scared the crap out of me because it sounded like a gun shot. I pulled off the road immediately and popped the hood - all was well. I was about to continue on and just happened to see the cap on the tank was AWOL - I was like huh, that's crazy! I looked in the tank and there was no coolant in it or anywhere else so it must have been air.

The cap blew off the tank so hard that it put a dent on the underside of the hood. Luckily I was able to find the cap on the opposite side of the road. Never happened again.

 

[YY1]

I'm using a heavy gauge plastic "water bottle" I got for $5 at a thrift store.

After figuring out I needed 48 oz capacity rather than 16 or 32, it works great.

Hose from rad neck through top opening held close to the bottom by gravity and curvature (and one twist tie).
As long as the hose end is below the water line it's :sealed".

It's about mid way height of radiator.

I check to make sure it's about 1/2 full every few trips.

 

[Pshas192]

I use a Mr. Gasket tank. It does what you want and looks great.

 

[Dana67Dart]

One day while driving down the road the cap blew off of it and went into the woods

That's why the system MUST be vented, the water in the rad only leaves the the rad because it has expanded. If it can't get out of the rad it will expand and pressurize the cooling system to greater than 16 lbs.

The 16 lbs cap allows the air ( or coolant if it's 100% full) to escape out maintaining 16 lbs in the system.

If the catch container is sealed then no air or coolant can leave the system so the 16 lbs cap is moot.

The system will build pressure till you have a catastrophic failure.

The "catch" / "overflow" sold with sealed caps and no other venting are a bomb waiting to happen.

If you want the lines at the bottom then one must extend internally to almost the top. And the other can be at the bottom.

That way as it fills the air above the existing coolant can escape and if too much coolant goes into the bottle it too will escape the same way.


Also don't confuse modern car "closed" cooling systems for anything but 1950s tech. All they do is move the rad cap to the bottle which is pressurized and only 1/2 full of coolant. When the coolant expands, air escapes through the pressure cap, and when it cools it is pushed back in by the atmosphere.. it's the same as having an air pocket at the top of the rad tank. It's not kind of the same it IS the same.

 

[Dana67Dart]

It's hard to see but the Mr gasket MRG-9135

Has a small vent hole in the top of the tank

Im not pushing that bottle just noting it.