# Downflow or Crossflow-which cools best?



## Sdpepper (Jun 3, 2021)

I'm a new owner of a 67 400ci GTO. I want to install a new direct fit aluminum radiator. Asking experienced GOAT owners if I should go with a downflow or crossflow type? Also, what brand have you found to be of good quality and cooling performance? Thanks


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## armyadarkness (Dec 7, 2020)

I WOULD SAY COLD CASE, GET THE ONE THEY LIST FOR YOUR CAR. Sorry for the caps lock

Jersey weather was mid 90's and pure humidity, all weekend long. I did several car shows, cruises, and explorations, totaling at least 100 miles, each day, in the heat of the day.



Exhaust crossover not blocked.
Cold Case aluminum, two core radiator.
Flow Cooler iron pump (old style).
Drilled t stat.
No radiator reservoir.
No inner fender debris flaps.
No radiator seals.
No fuel return.
The car between 160 and 180 all day, climbing to 200 when sitting. After sitting or low speed cruising, full throttle use just caused it to bog and sputter, but, it cleared up if you stayed in it, which leads me to believe that it's hot fuel.

In any event, I have room for improvement now.


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## michaelfind (Dec 14, 2018)

Sdpepper said:


> I'm a new owner of a 67 400ci GTO. I want to install a new direct fit aluminum radiator. Asking experienced GOAT owners if I should go with a downflow or crossflow type? Also, what brand have you found to be of good quality and cooling performance? Thanks





armyadarkness said:


> I WOULD SAY COLD SASE, GET THE ONE THEY LIST FOR YOUR CAR. Sorry for the caps lock
> 
> Jersey weather was mid 90's and pure humidity, all weekend long. I did several car shows, cruises, and explorations, totaling at least 100 miles, each day, in the heat of the day.
> 
> ...


And from the humid, hot environment of central Texas, another vote for Cold Case. I am very impressed with the improvement in cooling.


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## Sdpepper (Jun 3, 2021)

armyadarkness said:


> I WOULD SAY COLD CASE, GET THE ONE THEY LIST FOR YOUR CAR. Sorry for the caps lock
> 
> Jersey weather was mid 90's and pure humidity, all weekend long. I did several car shows, cruises, and explorations, totaling at least 100 miles, each day, in the heat of the day.
> 
> ...


Thanks for the recommendations. Can I ask if the thermostat you mention is the Robert Shaw high flow type? I think that kind is drilled, correct? Also, did your Cold Case come with shrouded electric fans or are you using the clutch fan?


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## Sdpepper (Jun 3, 2021)

michaelfind said:


> And from the humid, hot environment of central Texas, another vote for Cold Case. I am very impressed with the improvement in cooling.


Looks like Cold Case has two votes here. Is your radiator the one with the electric fans or not? Was it direct fit?


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## armyadarkness (Dec 7, 2020)

Sdpepper said:


> Thanks for the recommendations. Can I ask if the thermostat you mention is the Robert Shaw high flow type? I think that kind is drilled, correct? Also, did your Cold Case come with shrouded electric fans or are you using the clutch fan?


I use the Mr Gasket thermostats, which are high-flow Robert Shaws, and then I drill three, 3/16, bypass holes in them. I'm not aware of any TStats coming with the bypass holes.

As for fans, I just use a good old flex fan. I like the noise.


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## armyadarkness (Dec 7, 2020)

Sdpepper said:


> Looks like Cold Case has two votes here. Is your radiator the one with the electric fans or not? Was it direct fit?


There are two direct fit Cold Casefans for a 67. One is higher than the other and theyre not interchangeable, so you need to measure. Make sure that you flush the block out very well and take the appropriate steps to clean the system and prevent rust. Those things are major contributors to a cool running car, and you dont want to start flushing crap after the new radiator goes in.


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## O52 (Jan 27, 2019)

armyadarkness said:


> There are two direct fit Cold Casefans for a 67. One is higher than the other and theyre not interchangeable, so you need to measure.


A/C cars have a different core support and the larger radiator. But as Army said, verify the measurements.

And unless you want to have a custom radiator built, 64-67 GTOs had the Downflow radiator.


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## michaelfind (Dec 14, 2018)

Sdpepper said:


> Looks like Cold Case has two votes here. Is your radiator the one with the electric fans or not? Was it direct fit?


I'm trying to keep a generally stock appearance so I went without the electric fans. I did change to the heavy duty fan clutch and added a fan shroud. It fit very well. I also used the "radiator paint" on the tanks and outside to keep the more stock appearance.


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## armyadarkness (Dec 7, 2020)

michaelfind said:


> I'm trying to keep a generally stock appearance so I went without the electric fans. I did change to the heavy duty fan clutch and added a fan shroud. It fit very well. I also used the "radiator paint" on the tanks and outside to keep the more stock appearance.


You got a shroud for the Cold Case? Where? Id like to see it. One of the scariest jobs there is... working under the hood, with the engine running, on an unshrouded flex fan.


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## Sdpepper (Jun 3, 2021)

michaelfind said:


> I'm trying to keep a generally stock appearance so I went without the electric fans. I did change to the heavy duty fan clutch and added a fan shroud. It fit very well. I also used the "radiator paint" on the tanks and outside to keep the more stock appearance.





michaelfind said:


> I'm trying to keep a generally stock appearance so I went without the electric fans. I did change to the heavy duty fan clutch and added a fan shroud. It fit very well. I also used the "radiator paint" on the tanks and outside to keep the more stock appearance.


im curious to know where you got the radiator paint which I presume is black.


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## michaelfind (Dec 14, 2018)

armyadarkness said:


> You got a shroud for the Cold Case? Where? Id like to see it. One of the scariest jobs there is... working under the hood, with the engine running, on an unshrouded flex fan.


I think I bought the shroud through Ames. I know what you mean. Every time I'm checking timing, my left hand stretched over to the distributor cap, my right hand holding the timing light, and I'm trying to see the timing marks without getting directly in line with the fan blades. Just in case...


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## michaelfind (Dec 14, 2018)

Sdpepper said:


> im curious to know where you got the radiator paint which I presume is black.


I used the Eastwood Radiator black, satin finish. It is supposed to be thinner to not decrease cooling fucntion. I used a good amount on the tanks but was very light on the fins. They have in on amazon. I think Ames sells it too. I found a good deal on ebay for mine.


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## armyadarkness (Dec 7, 2020)

michaelfind said:


> I think I bought the shroud through Ames. I know what you mean. Every time I'm checking timing, my left hand stretched over to the distributor cap, my right hand holding the timing light, and I'm trying to see the timing marks without getting directly in line with the fan blades. Just in case...


Yeah a buddy of mine says that he once saw the rivets let loose on a flex fan. Those things are like scalpels


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## Ollie (Aug 7, 2021)

Sdpepper said:


> Thanks for the recommendations. Can I ask if the thermostat you mention is the Robert Shaw high flow type? I think that kind is drilled, correct? Also, did your Cold Case come with shrouded electric fans or are you using the clutch fan?


The Robert Shaw is pre drilled.


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