Thread: Radiator recovery

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I recently discovered that my shinny cool radiator recovery tank could not maintain a full level capacity in my radiator on the hot California days, if the radiator was full the tank would spill over occasionally when the weather turned hot.

I didn’t have the space under the hood to increase the recovery tank size and I was limited for placement of an additional catch can. Seems the perfect place for the catch can on my 36 Ford was under the front grill just in front and below the radiator, there I could tuck it up out of harms way.

Problem, catch cans are designed to stand up (inlet on the bottom, outlet on the top, but I only have room enough to lay it down horizontally. Solution, modify the catch can’s inlet and outlet to allow it to re-circulate in the horizontal position as outlined below, hopefully this will help other solve similar problems.

I'm not certain I understand the situation but, are you saying the radiator was full, and the catch can was full also? But it was purging some when it got hot?

When I say it, it sounds perfectly normal as there nowhere else to contain fluid.

But are you really saying you don't think it's pulling fluid back from the catch can? Sorry for the confusion!

The small recovery tank (tube type along side my radiator) did not have enough capacity to maintain a proper level in the radiator. On hot days (100° +) the radiator would purge more than the tank could hold, then on cool down after the radiator recovered what was in the tank, it would pull air in.

The additional catch can adds ample space for full recovery and no more air problems.

If I may??? How important is the catch can??? Most of the older cars didn't have them such as my '62 so should I see about adding one?

You only need a recovery tank if you’re using a sealed system, most of the older cars like yours were an open system (purged to the ground). In a sealed system the radiator purges to the tank then recovers the fluid on cool down. A sealed (recovery) system will maintain the coolant levels and control the air in the system better than an open (non recovery) type. Less air less = better cooling transfer and less corrosion in the system.

If you decide to add the recovery tank you will need to replace the radiator cap with a recovery type cap of the same pressure your system is operating at presently. Careful, do not increase the pressure cap higher than what the radiator is rated at, it can damage the radiator.

Originally Posted by 36 sedan

The small recovery tank (tube type along side my radiator) did not have enough capacity to maintain a proper level in the radiator. On hot days (100° +) the radiator would purge more than the tank could hold, then on cool down after the radiator recovered what was in the tank, it would pull air in.

The additional catch can adds ample space for full recovery and no more air problems.

You can solve that problem by some judicious attention to your recovery tank level. Go out for a drive and get the engine up to temp, then as you pull in to your garage top off your recovery tank to the point that it is about to over flow. As it cools any air in the radiator will shrink, pulling coolant in to replace that volume when it cools completely. Repeat that cycle several times, and eventually you will purge all of the air from your radiator and it will be 100% fluid. At that point you should not see any loss of coolant from the recovery tank.

Originally Posted by MelloYello

If I may??? How important is the catch can??? Most of the older cars didn't have them such as my '62 so should I see about adding one?

Yes, Em, you should add a new radiator cap that allows fluid to back flow into the radiator as it cools, and a recovery tank to get your system purged of air for maximum cooling efficiency. In the old days there was a pocket of air on top of the radiator, and that's what caused most of the corrosion in the cooling system. With the new recovery tank in place, fill your radiator to the brim with your 50/50 mix of anti-freeze and water, then add the same mix of coolant to the recovery tank, about 1/2 way between the "Cold" and "Hot" marks. Go for a drive, and once the system cools completely (might take a week in Texas this time of year ) I expect you'll see the level in the bottle down a bit. Top it off to the "Cold" level, and keep an eye on it for a while to be sure it doesn't go too low. You don't want it to go dry or you'll suck air back into the system.

Originally Posted by MelloYello

If I may??? How important is the catch can??? Most of the older cars didn't have them such as my '62 so should I see about adding one?

Most drag strips won't let you on the track without one, antifreeze is a little slippery

We used to make catch cans from a miller or bud can! If your talking about a coolant recovery system, that's a different thought process.

This'll raise some hair but, if you start out with the radiator not completely topped off, you'll have room for expansion and not overload the catch can\ recovery tank.

Originally Posted by rspears

You can solve that problem by some judicious attention to your recovery tank level. Go out for a drive and get the engine up to temp, then as you pull in to your garage top off your recovery tank to the point that it is about to over flow. As it cools any air in the radiator will shrink, pulling coolant in to replace that volume when it cools completely. Repeat that cycle several times, and eventually you will purge all of the air from your radiator and it will be 100% fluid. At that point you should not see any loss of coolant from the recovery tank.

Absolutely correct, unless your way cool chrome hot rod recovery tank is too small as mine was.

Not trying to tell anyone what to do, just sharing what I did to correct my problem in hopes it will help some others.

Sorry for the confusion.

Originally Posted by 36 sedan

Absolutely correct, unless your way cool chrome hot rod recovery tank is too small as mine was.

Not trying to tell anyone what to do, just sharing what I did to correct my problem in hopes it will help some others.

Sorry for the confusion.

No Way! the confusion was all mine! And thanks for sharing a solution to the problem!!! There are always 2 ways to approach a problem and venues like this let us share those.

Thanks for sharing and being a gentleman at all times!

Originally Posted by 36 sedan

The small recovery tank (tube type along side my radiator) did not have enough capacity to maintain a proper level in the radiator. On hot days (100° +) the radiator would purge more than the tank could hold, then on cool down after the radiator recovered what was in the tank, it would pull air in.

The additional catch can adds ample space for full recovery and no more air problems.

Originally Posted by 36 sedan

Absolutely correct, unless your way cool chrome hot rod recovery tank is too small as mine was.

Not trying to tell anyone what to do, just sharing what I did to correct my problem in hopes it will help some others.

Sorry for the confusion.

What I'm saying is that even with a relatively small tank (mine measures 2"OD x 17" tall) one can purge the air and have a cushion of fluid in reserve.

34-40, thanks for the kind words.

Roger, no disrespect intended and I’m not doubting your method, I’ve used that same method for years.

Unfortunately, this time it simply was not working for me. Occasionally on a hot day the tank would spill over, sometimes I wouldn’t notice it and it would suck air back.

My OCD would not except that as OK, even occasionally, the what ifs set in and worried me (what if it overheats, what if a pet drinks the spillage). I really didn't like the idea of the tank not working correctly, but I liked the looks of the way cool chrome tube. So, not having the space to change the tank to a bigger way cool chrome tube, I compromised and added the catch can tucked up out of site for additional fluid storage.

It gives no trouble now, it was a simple inexpensive fix, less than the cost of the antifreeze I was spilling and it took only a few minutes to do. It is now working perfectly and there is less of a chance of a pet drinking any spilled antifreeze.

Finally I can sleep, my OCD is satisfied, the world is a safer place.

Originally Posted by 36 sedan

.......Finally I can sleep, my OCD is satisfied, the world is a safer place.

36 sedan,
Not to beat a dead horse, and as you said no disrespect intended at all, but it seems to me that you have not really changed your situation other than adding volume to your recovery tank that you cannot see. With the new quart sized tank mounted low, beneath the radiator with it's overflow feeding your "original", smaller chrome recovery tank (for easy access for filling & checking level, I assume) once the system is full and purged the bottom tank is going to be 100% coolant and you'll have some amount of coolant in your upper tank to give a visual on coolant level. I'm not sure how you intend to get the initial charge of fluid in the bottom reservoir other than over filling the top one and letting it dribble down the recovery line, but in operation it will burp air, and suck back fluid from the upper tank repeatedly until it is full with no air at the top, even with your tube configuration. At that point you'll be running with your top tank volume, and if it was too small before it will be too small now. As the radiator "burps" the little tank will over flow and then pull back into the larger tank but you won't know the level in that one so you'll add to the little tank and it will go through the cycle again, filling the bottom tank, topping off the upper tank, and waiting for the next burp.

I apologize if I mis-understand your plumbing configuration, but if it's plumbed as I describe I think you're going to see a puddle, or a dry upper tank before long.

LOL! I see the confusion now.

I have a 36, the grill goes below the radiator, the catch can is visible to me through the lower part of my grill (most won’t see it is there). The catch can runs at a little over half full, my chrome recovery tank is used to fill the catch can and take any expanding fluids the catch can can’t hold above the half full level.

The radiator appears to be real happy now (or is that me), anyway, so far it has worked even in our recent heat wave with the A/C operating.

Thanks all for your concerns, I appreciate your helpful thoughts.

Just wanted Y'all to know that I read all of these comments and now I'm trying to let it soak in. thanks, meller