Converting Windshield washer tank to coolant recovery tank for 70 Cuda

[tman]

Has anyone done this modification to keep stock appearances?  I see that you would need the MANUAL (non electric) washer tank.  Is the nipple at the bottom of this tank same size for the radiator overflow hose? or is it too big or too small?  I currently have an electric windshield tank and my overflow hose points to driver side. 
Getting a bit tired filling the radiator after several drives. 
Thanks for the input.

[burdar]

The "FULL" level of a stock radiator is NOT at the very top.  There is a plate directly under the cap that's maybe an inch or two down from the top.  That plate is the full level.  If you keep the radiator at this level, you won't puke any coolant out.(unless the engine gets hot)

I'm not sure about the nipple size on the windshield washer bottle.  I assume it's way too small.  You could use an electric bottle.  That has a large hole in it for the pump to attach.  You'd have to buy an AN fitting to attach to the bottle and then a hose nipple to screw onto the AN fitting.

[Katfish]

I like the idea, but my radiator is on drivers side.
What's your plan for routing to passenger side?

[cudabob496]

The "FULL" level of a stock radiator is NOT at the very top.  There is a plate directly under the cap that's maybe an inch or two down from the top.  That plate is the full level.  If you keep the radiator at this level, you won't puke any coolant out.(unless the engine gets hot)

I'm not sure about the nipple size on the windshield washer bottle.  I assume it's way too small.  You could use an electric bottle.  That has a large hole in it for the pump to attach.  You'd have to buy an AN fitting to attach to the bottle and then a hose nipple to screw onto the AN fitting.

When engine comes to normal temp, I think you'll always get some overflow, if rad is full, due to expansion of the fluid.  I would get about a cup per trip.

[burdar]

Exactly, that's why the FULL mark isn't at the top of the rad.  It's down lower.  If it was at the top, you would always be spitting out coolant until the system equalized.  Back in the day, you didn't fill a rad all the way to the top.  You left some empty space at the top for expansion.  Just because you have coolant in your overflow bottle, doesn't mean you need to put it back in the rad.  The over flow is there just so you don't put antifreeze onto the ground.

There's nothing wrong with adding a recovery system, but if you are just adding one because you are finding antifreeze in your over flow tank, you are over filling the system to start with.   Keeping the level down an inch or two won't affect the cooling system and you won't puke any antifreeze out onto the ground.

[cudabob496]

Coefficient of thermal expansion of water = 0.00021 (1/oC)

1 deg C rise in the water tank = 1.0002 Unit Volume Rise

10C = 50F
93C = 200F

If temp of coolant goes from 50F to 200F, thats 83C rise in temp.

Say coolant system vulume is 4 gallons. get unit volume rise of 4 x .0166 = .0664 gallons

= .0664 x 128 oz per Gal, = 8.5 oz = about a cup expansion.

[cudabob496]

Exactly, that's why the FULL mark isn't at the top of the rad.  It's down lower.  If it was at the top, you would always be spitting out coolant until enough puked out.  Back in the day, you didn't fill a rad all the way to the top.  You left some empty space at the top for expansion.  If you are constantly adding coolant to keep the rad completely full, then you will constantly puke it out.  Leave it down lower(at the proper FULL mark) and you won't have that problem. Just because you have coolant in your overflow bottle, doesn't mean you need to put it back in the rad.  The over flow is there just so you don't put antifreeze onto the ground.

There's nothing wrong with adding a recovery system, but if you are just adding one because you are finding antifreeze in your over flow tank, you are over filling the system to start with.   Keeping the level down an inch or two won't affect the cooling system and you won't puke any antifreeze out onto the ground.

Prob with my system, is even when coolant in rad was 3 inches below top, I would get my overflow bottle almost full in a month.
Its a 1 qt bottle.

[burdar]

Once the system equalizes, it will stop pumping it out into the overflow bottle.  Just empty the overflow into a jug in the garage and don't add it back to the rad.  The system will equalize and you'll stop filling the overflow.

[cudabob496]

Once the system equalizes, it will stop pumping it out into the overflow bottle.  Just empty the overflow into a jug in the garage and don't add it back to the rad.  The system will equalize and you'll stop filling the overflow.

unfortunately, my system will keep filling overflow bottle. Maybe I have some seapage at the cap?
and every month the rad level goes down about an inch.
so, for me, this recovery system is great.  Rad is always full, and no more dumping recovery tank.

[CudamanTom]

Once the system equalizes, it will stop pumping it out into the overflow bottle.  Just empty the overflow into a jug in the garage and don't add it back to the rad.  The system will equalize and you'll stop filling the overflow.

  I'm with Burdar on this. You shouldn't have to touch it. BUT, if you have a problem (leaky cap, overheating and such) you might have to keep adding. But that's not normal. May be something to look into IMHO.

[cudabob496]

wonder if having an alum radiator is a factor?

I guess the recovery system is the way to go, if you have to keep emptying your overflow bottle.

So, why do new cars go to a recovery system, considering what Burder is saying? Probably because
its self contained, and keeps the sytem full without air!

I think even a recovery tank needs filling once in a while, as there always must be some tiny
amount of water leakage from an engine over time.

[CudamanTom]

I guess the recovery system is the way to go, if you have to keep emptying your overflow bottle.

So, why do new cars go to a recovery system, considering what Burder is saying? Probably because
its self contained, and keeps the sytem full without air!

I think even a recovery tank needs filling once in a while, as there always must be some tiny
amount of water leakage from an engine over time.

If you have to keep emptying your overflow bottle, you have a problem.
The newer systems need a place to expand and retract and the overflow tank keeps it full with fluid going in and out.
Yes, in a newer model vehicle a little fluid may escape over time but you shouldn't have to top off except every couple years, if that. And I'm talkin a very little bit.

[cudabob496]

If you have to keep emptying your overflow bottle, you have a problem.
The newer systems need a place to expand and retract and the overflow tank keeps it full with fluid going in and out.
Yes, in a newer model vehicle a little fluid may escape over time but you shouldn't have to top off except every couple years, if that. And I'm talkin a very little bit.

Well, been doing it for 15 years. Maybe radiator neck surface is not perfectly flat for the radiator
cap to seal.  Anyway, the recovery tank now deals with the issue.

[tman]

I don't have an overheat issue with mine.  Currently the level is about 2.5 inches below the neck.  At its current state, I don't think anymore coolant is coming out of the overflow.  I like the idea that there would be no air in the upper radiator tank.  I only fill it to the mark burdar mentions.  I found a post where an owner used his washer tank for their coolant recovery.  Its about 2/3rds down from pg 1 in name of "second 70."  I would still like to see someone who actually did the mod to post what they did to make it work.  Good comments coming in.  As far as routing the overflow hose, a saw a post where they say just get a longer hose that exits to the left, go down and then route to the bottom of the washer tank.  They claim it will still vacuum fluid back to radiator.  Its seems a long way and I would like to see testimonial that it indeed works.  AN fitting using a electric tank sounds good, but if they guy who just said, "hook the hose to the bottom of tank" and that is it.  My perception of his statement is he just connected it to the manual tank nipple. 

http://board.moparts.org/ubbthreads/ubbthreads.php/ubb/showflat/Number/8258784/site_id/1

[cudabob496]

I don't have an overheat issue with mine.  Currently the level is about 2.5 inches below the neck.  At its current state, I don't think anymore coolant is coming out of the overflow.  I like the idea that there would be no air in the upper radiator tank.  I only fill it to the mark burdar mentions.  I found a post where an owner used his washer tank for their coolant recovery.  Its about 2/3rds down from pg 1 in name of "second 70."  I would still like to see someone who actually did the mod to post what they did to make it work.  Good comments coming in.  As far as routing the overflow hose, a saw a post where they say just get a longer hose that exits to the left, go down and then route to the bottom of the washer tank.  They claim it will still vacuum fluid back to radiator.  Its seems a long way and I would like to see testimonial that it indeed works.  AN fitting using a electric tank sounds good, but if they guy who just said, "hook the hose to the bottom of tank" and that is it.  My perception of his statement is he just connected it to the manual tank nipple. 

http://board.moparts.org/ubbthreads/ubbthreads.php/ubb/showflat/Number/8258784/site_id/1

I think any tank will work, as long as you come in at the bottom of the tank, with your hose, and as long as the hose
is durable.  May have to put a little more in tank initially, to fill the hose volume. Look on ebay under recovery tank, and there
are tons of different designs. One of these days I may get around to putting my recovery tank where it can't be seen. For now,
I think I'll paint it yellow.