Radiator Puke Tank

[nvrstuk]

Not stock you are asking for? Not stock for a Bronco or not stock for any OEM?

I had to go with a 32oz reservoir due to engine output which was new to me. Stock engines don't need as large a reservoir as higher output engines due to heat output capacity which directly transfers into the amount of water "burped" out into the reservoir.

I had problems figuring this out for years as I was running a smaller capacity reservoir and after topping off the radiator I would notice after a while that upon removing the radaitor cap before trips or wheeling the coolant level in the radiator would be 2" low and it would never go lower.

Well, after calling and researching a bunch I learned that I needed a larger reservoir. Seems simple but why? My 418 never burped this much coolant with the same radiator/cooling system so why this one.

Anyway, if you are stock or close to it for hp output you can use OE or go aftermarket which is usually alum so it looks pretty but costs a ton more. Capacity is the key.

Since I don't run inner fenders, my frt axle is moved forward, I have 40" tires on a narrowed D60 it limited my options for hanging a reservoir, I mounted a relatively narrow but tall alum cylinder within a 1/2" of my radiator tank on the pass side. Fits perfect, impervious to rocks flying off the tires AND it works perfect.

My radiator level stays at the top now when filled since the larger capacity reservoir handles the extreme amount of coolant that is "burped" compared to before. More heat generated = more coolant heated quickly that gets burped out. Makes sense, just never seemed to have the issue before.

Hope this helps someone.

 

[DirtDonk]

Local friend here had the same problem with his stock 5.0 mustang engine equipped 74.
It was always puking a little out the overflow and always settling at a lower level. He had a nice aluminum aftermarket tank, but it was very tiny, so we suggested getting a bigger one.
I think he’s doing engine work right now but I don’t know if he’s changed the tank yet.
I’m just guessing, but it looked like about half the size of the OEM tank.

 

[nvrstuk]

Local friend here had the same problem with his stock 5.0 mustang engine equipped 74.
It was always puking a little out the overflow and always settling at a lower level. He had a nice aluminum aftermarket tank, but it was very tiny, so we suggested getting a bigger one.
I think he’s doing engine work right now but I don’t know if he’s changed the tank yet.
I’m just guessing, but it looked like about half the size of the OEM tank.

Hope this helps him..
I should have mentioned that my radiator core is now appr 500sq in compared to appr 280sq in for a stock EB and the tanks are very large. Pretty sure it doesn't change anything here but the more coolant and core area the better imo. Cardboard and good t-stats can fix any overcooling problem!

 

[Johnnyb]

https://www.amazon.com/dp/B08FJGGVDB/?tag=cbama-20

 

[jamesroney]

It actually might change things. The liquid only expands at the same rate for a given temperature I'm guessing, but having more volume to start with would naturally increase the total fluid expansion. Necessitating a larger catch tank as well.
In theory?

Paul

Well, that' a pretty horrid theory. The increase in volume of water in relation to temperature is not a theory. It is also not a fact. Water reaches it's maximum density at about 4 degrees C. So if you go from 4C to 3C...it actually gets larger. Also, if you go from 3 degrees to 4 degrees...it gets smaller.

So it doesn't always increase volume with an increase in temperature. These aren't theories. They are simply observations from reactions to physical laws. Generally, water from 20C to 99C will increase about 4% by volume. This is the result of empirical testing, and observation. So if someone proposed a hypothesis that having more volume would increase the total expansion... that just becomes a confirmation thru observation. It doesn't describe the why, or the how.

So yes, 2 gallons of water will increase in volume by about 10 ounces, and 4 gallons of water will increase by 20 ounces. (from ambient to about boiling) If you are foolish enough to fill your radiator above it's capacity...that expansion will result in overflow. The capacity of a down flow radiator is usually reduced by 4 percent to allow for expansion. Some even have sunken fill necks in the top tank to prevent over filling. There is no decrease in cooling capacity in a down flow radiator if you reduce the fill level. A cross flow radiator will exhibit a reduction in cooling capacity if the upper fins are not wet. In this case, the radiator must be de-rated to allow for under-filling. If you need the full capacity of the radiator, then a surge tank may be installed to enable complete filling. You will find one on every V8 Bronco from 66-68. If you design your radiator such that over-filling (or complete filling) is not necessary...you can leave room for expansion in the radiator. Every V8 Bronco from 70-72 is designed this way. Once you decide to maximize the cooling capacity of the radiator, and ensure tube coverage, then a recovery reservoir is appropriate. The capacity of that reservoir should not be less than 4 percent of the coolant volume. Add a reasonable safety factor and you get to @nvrstuk and his 32 ounce solution. (maybe fill to 25% full, operating from 25% to 75%, leaving some headroom.)

Cooling systems designed for full coverage have coolant recovery bottles. Cooling systems designed for expansion in the radiator have overflow bottles. Properly designed cooling systems that have excess cooling capacity and appropriate fill levels have hoses that run to the ground.

I was going to put a puke can on my Bronco. But you let me convince myself that I don't need it. So you just saved me about $60.00. Thanks!



The fill neck on a Bronco V8 can be below the highest row of tubes. This allows room for expansion in the radiator. The fill line should be about an inch or two below the fill neck.

 

[DirtDonk]

The capacity of that reservoir should not be less than 4 percent of the coolant volume. Add a reasonable safety factor and you get to @nvrstuk and his 32 ounce solution. (maybe fill to 25% full, operating from 25% to 75%, leaving some headroom.)

So I was correct. A larger radiator might require a larger recovery tank.
In theory?

I was going to put a puke can on my Bronco. But you let me convince myself that I don't need it. So you just saved me about $60.00. Thanks!

You're welcome.
But I don't always add them for my health. It's for yours as well.
I don't like spitting anti-freeze mixtures (or even dirty water) down on the pavement any more than the rest of the tree-hugging Bronco owners did. Since we have an option not to do that, I prefer to catch and return instead.
Rather than release...

Paul

 

[StnePny]

Local friend here had the same problem with his stock 5.0 mustang engine equipped 74.
It was always puking a little out the overflow and always settling at a lower level. He had a nice aluminum aftermarket tank, but it was very tiny, so we suggested getting a bigger one.
I think he’s doing engine work right now but I don’t know if he’s changed the tank yet.
I’m just guessing, but it looked like about half the size of the OEM tank.

DirtDonk....my question is........why hasn't anyone tried the the '68 Overflow set....?

 

[Oldtimer]

And my 68, from the factory, never had a overflow/recovery tank.
Just a hose down the side of the pass end tank, that spit on the ground.
I don't recall if bottom of fill neck was below top cooling tubes. That was 3 or 4 radiators ago.

 

[DirtDonk]

DirtDonk....my question is........why hasn't anyone tried the the '68 Overflow set....?

Don't know that one Pny. Would you be talking about the surge tank that was factory installed?
If so that would be an extremely expensive overflow and not actually be an overflow. Assuming you could even find a good one that is.
Of course, they can be made just like any other tank can. But it's not necessarily a solution, it's expensive, and to most people it clutters up the engine compartment too much.

 

[DirtDonk]

And my 68, from the factory, never had a overflow/recovery tank.
Just a hose down the side of the pass end tank, that spit on the ground.

The factory did not install recovery/return tanks until the '73 model year (or perhaps very late '72's like so many other changes were). Did yours have a high-mounted surge tank in the top radiator hose?
If not, that would be interesting. Do you know what month your '68 was built in? Just curious if you have a late build that might have already had it's surge tank eliminated, as happened for the '69 model year.
Although, it might be the other way 'round too. I seem to remember a friend who, in about '74, bought a beautiful '69 that I thought also had a surge tank.
But it was already way customized for the time with new paint, fully frame-integrated full roll cage, built C4 with shift kit that could chirp the tires between first and second, and several other goodies. Maybe the owner just liked the old design and decided to add one?

Did your original radiator have a fill neck? You mentioned an overflow tube on the passenger side and that's where the normal filler neck/cap is. But on older versions with the surge tank there was no filler neck on the radiator itself.

I had one of those until recently. Wonder where that sucker got too...

Paul

 

[Oldtimer]

Marti says it was built 3/25/68.
Fill neck was in original radiator.
Never had the high surge tank in top radiator hose.
However Lutz Ford kept trying to sell me two upper radiator hoses (with a gap for the surge tank).
I finally took the original single hose to the parts counter, and after a couple of calls to district parts desk they figured out which hose I needed.

 

[76BroncoPete]

Not stock you are asking for? Not stock for a Bronco or not stock for any OEM?

I had to go with a 32oz reservoir due to engine output which was new to me. Stock engines don't need as large a reservoir as higher output engines due to heat output capacity which directly transfers into the amount of water "burped" out into the reservoir.

I had problems figuring this out for years as I was running a smaller capacity reservoir and after topping off the radiator I would notice after a while that upon removing the radaitor cap before trips or wheeling the coolant level in the radiator would be 2" low and it would never go lower.

Well, after calling and researching a bunch I learned that I needed a larger reservoir. Seems simple but why? My 418 never burped this much coolant with the same radiator/cooling system so why this one.

Anyway, if you are stock or close to it for hp output you can use OE or go aftermarket which is usually alum so it looks pretty but costs a ton more. Capacity is the key.

Since I don't run inner fenders, my frt axle is moved forward, I have 40" tires on a narrowed D60 it limited my options for hanging a reservoir, I mounted a relatively narrow but tall alum cylinder within a 1/2" of my radiator tank on the pass side. Fits perfect, impervious to rocks flying off the tires AND it works perfect.

My radiator level stays at the top now when filled since the larger capacity reservoir handles the extreme amount of coolant that is "burped" compared to before. More heat generated = more coolant heated quickly that gets burped out. Makes sense, just never seemed to have the issue before.

Hope this helps someone.

Good info thanks for posting

 

[Oldtimer]

. . . . then a surge tank may be installed . . . . You will find one on every V8 Bronco from 66-68.
. . . you can leave room for expansion in the radiator. Every V8 Bronco from 70-72 is designed this way.

@jamesroney
My 68 never had a surge tank.
What did Ford do with the 69 Broncos? Surge tank, leave room for expansion, ?

 

[jamesroney]

@jamesroney
My 68 never had a surge tank.
What did Ford do with the 69 Broncos? Surge tank, leave room for expansion, ?

Yeah, you keep saying that...and I'm not going to argue with you.

But every other 68 Bronco with a 289 got the surge tank, and the single piece upper radiator hose didn't exist until the 1969 model year. So yes, it is possible that you have the only Bronco produced in 1968 that someone left the assembly line, ran to a hardware store, bought a hose, ran to a radiator shop, invented a radiator with a cap on it, brought it BACK to the assembly line, and installed it after the engine was assembled, and before it was installed in the chassis. Then they managed to delete the surge tank, upper hose, tank to thermostat hose, and the hardware. All in less than TakT time of about 90 seconds.

I haven't had a chance to check the MPC on service parts for your build date. It is also possible (and vastly more likely) that there was a mid 68 running change in production. March is about 2/3 of the way thru the year. But I think the change happened in the 69 model year. Could have happened in March of 68.

Easy enough to verify. I figured someone that actually knew would chime in.

 

[toddz69]

What did Ford do with the 69 Broncos? Surge tank, leave room for expansion, ?
[/QUOTE]
The '69s were like the '70-'72s that James mentioned above. Had a tube running down the side of the pass side tank.

Todd Z.

 

[nvrstuk]

Yeah, you keep saying that...and I'm not going to argue with you.

But every other 68 Bronco with a 289 got the surge tank, and the single piece upper radiator hose didn't exist until the 1969 model year. So yes, it is possible that you have the only Bronco produced in 1968 that someone left the assembly line, ran to a hardware store, bought a hose, ran to a radiator shop, invented a radiator with a cap on it, brought it BACK to the assembly line, and installed it after the engine was assembled, and before it was installed in the chassis. Then they managed to delete the surge tank, upper hose, tank to thermostat hose, and the hardware. All in less than TakT time of about 90 seconds.

I haven't had a chance to check the MPC on service parts for your build date. It is also possible (and vastly more likely) that there was a mid 68 running change in production. March is about 2/3 of the way thru the year. But I think the change happened in the 69 model year. Could have happened in March of 68.

Easy enough to verify. I figured someone that actually knew would chime in.

I'll look thru my slides one day to prove this wrong. My '68 did NOT have a surge tank. It DID have a one pc upper rad hose. It did NOT have a tank to t-stat hose.... and of course it didn't have the hardware.

So I'm assuming the SAME guy that "left the assembly line" (your quote) and made it to the hardware store to get all the parts did it for my '68 Sport also.

I bought this '68 Bronco with 289ci from the original purchaser back in '76 with 49,950 miles on it. NO work had been done to the Bronco in repairs (except common tuneups) other than dealer add on stuff like my cool old 102" whip antenna he had put on, fiberglass flares painted to match the body (which I still have hanging on the shop wall), custom rear wrap around bumper that was chromed to match the front.

I can call John the guy I bought it from to verify that absolutely zero engine work had been done except points and plugs when he owned it.

Someone is wrong about this and it's not me or Oldtimer. It's ok, I was wrong already once today and have a long way to go to fill my quota just for the day.

Have a good day all.

 

[DirtDonk]

Nothing ever surprises me anymore about Ford's often ignored penchant for running changes before, or after the expected start date for a certain part, option, paint color (or name and code!) or out and out fudging the year model designation (think P's and Q's) for Broncos.
Would not surprise me if it happened on other vehicles as well.
All the aftermarket shop manual printers got the information that '71 used the same wiring as the '70 and earlier. They did not, and every '71 (and one or two '70's I think) came with the later "72 style" wiring. Same for the change to fuse panels and wiring harnesses in the full size truck line between '75 and '76. Books say '76 used the same old 5-fuse panel, but so far every '76 I've ever checked out had the later 10-fuse panel instead.
During the transition to '73 models, they probably ran short of smog equipment, or certification qualifications, or ran afoul of waiting for the gummint to release the final specifications, or they just wanted to fudge a few more out before the more stringent requirements were implemented, or maybe even just ran short of overflow bottles(!) that kept Broncos coming off the production line that kept the '72 designations well into October of that year. Long past the traditional August transition.
Nothing illegal, immoral or fattening about doing things that way. Just messes up the people trying to plan for the support of said vehicles.
Heck, maybe it was just a bookkeeping error or being shorthanded at the time and not finishing the paperwork that delayed things.

But not having a surge tank on a later built '68? That doesn't even raise the radar or red flags or dispel any doubt that could have happened. Would not even surprise me to find out they ran no surge tank mid-way through the build, then added them back for the last couple of months of production again!

So nvrstuk, we heard that Oldtimer's '68 was built in March. Do you happen to know when yours was built? Might as well add it to the database.

Paul

 

[nvrstuk]

It actually might change things. The liquid only expands at the same rate for a given temperature I'm guessing, but having more volume to start with would naturally increase the total fluid expansion. Necessitating a larger catch tank as well.
In theory

Well, that' a pretty horrid theory. The increase in volume of water in relation to temperature is not a theory. It is also not a fact. Water reaches it's maximum density at about 4 degrees C. So if you go from 4C to 3C...it actually gets larger. Also, if you go from 3 degrees to 4 degrees...it gets smaller.

So it doesn't always increase volume with an increase in temperature. These aren't theories. They are simply observations from reactions to physical laws. Generally, water from 20C to 99C will increase about 4% by volume. This is the result of empirical testing, and observation. So if someone proposed a hypothesis that having more volume would increase the total expansion... that just becomes a confirmation thru observation. It doesn't describe the why, or the how.

So yes, 2 gallons of water will increase in volume by about 10 ounces, and 4 gallons of water will increase by 20 ounces. (from ambient to about boiling) If you are foolish enough to fill your radiator above it's capacity...that expansion will result in overflow. The capacity of a down flow radiator is usually reduced by 4 percent to allow for expansion. Some even have sunken fill necks in the top tank to prevent over filling. There is no decrease in cooling capacity in a down flow radiator if you reduce the fill level. A cross flow radiator will exhibit a reduction in cooling capacity if the upper fins are not wet. In this case, the radiator must be de-rated to allow for under-filling. If you need the full capacity of the radiator, then a surge tank may be installed to enable complete filling. You will find one on every V8 Bronco from 66-68. If you design your radiator such that over-filling (or complete filling) is not necessary...you can leave room for expansion in the radiator. Every V8 Bronco from 70-72 is designed this way. Once you decide to maximize the cooling capacity of the radiator, and ensure tube coverage, then a recovery reservoir is appropriate. The capacity of that reservoir should not be less than 4 percent of the coolant volume. Add a reasonable safety factor and you get to @nvrstuk and his 32 ounce solution. (maybe fill to 25% full, operating from 25% to 75%, leaving some headroom.)

Cooling systems designed for full coverage have coolant recovery bottles. Cooling systems designed for expansion in the radiator have overflow bottles. Properly designed cooling systems that have excess cooling capacity and appropriate fill levels have hoses that run to the ground.

I was going to put a puke can on my Bronco. But you let me convince myself that I don't need it. So you just saved me about $60.00. Thanks!



The fill neck on a Bronco V8 can be below the highest row of tubes. This allows room for expansion in the radiator. The fill line should be about an inch or two below the fill neck.

Good stuff but another item-

If I only need 4% reservoir capacity of my appr 384 oz system then I'd only need a pint capacity reservoir. That's what I had for decades but with the 460 stroker it would always burp about another pint or more on to the ground.

My theory based not on my ability to explain the physics behind it because I don't need to in this case (and most of you know I'm a numbers/engineer geek) but because I have a different situation than most Broncos that I tried to explain earlier.

When my HP numbers grew from a stock 289 to now 3+ times what the stock 289 ever generated the huge boiler fired heater I run now - called a 460stroker- generates a HUGE amount of btu's extremly quickly thereby (explained to me by an engineer at Griffin I think that's where it was) creating what he said was a much bigger rush/push/bubble/amount (for lack of a physics accepted term) of superheated water out thru the tstat and into the radiator. This "superheated" water as he put it created a large surge and expansion that would need to be expended out the overflow into the tank. Take an engine making 1/3rd the HP and the tank could be MUCH smaller he said. Hence the reason I needed to go to a full quart instead of 12+ oz or so which worked well for so long.

Back when I had my 289 or 351 with the tube running down to the ground the only time I dumped any fluid would be when the radiator was still accidently covered with cardboard from winter time. Pull that out and the water would sit a 1/2-1" below the neck pulling boat trailers, tent trailer, boat on top of the Bronco, over 12,000ft gravel mountain passes in 100deg heat with kids/6 weeks worth of gear- never mattered. It DOES matter with stooopid HP WHEN it is being generated tho.

 

[nvrstuk]

So nvrstuk, we heard that Oldtimer's '68 was built in March. Do you happen to know when yours was built? Might as well add it to the database.

Paul

Glove box is hanging on the wall in the shop. I can check when I have the energy to get off the sofa. (covid)

BTW, nicely worded. thanks

 

[nvrstuk]

And my 68, from the factory, never had a overflow/recovery tank.
Just a hose down the side of the pass end tank, that spit on the ground.
I don't recall if bottom of fill neck was below top cooling tubes. That was 3 or 4 radiators ago.

I know right...?? How many of this and that have we replaced over the decades? I keep track I guess because I do stuff like weigh almost everything that comes off or goes on my Bronco... I like details (usually the ones that don't matter! lol )
So for me it's been 5 radiators but 6 engines.