# Need advice! 3 core or 4 core



## gr868 (Jul 29, 2013)

Hello Everyone,
My brand new waterpump bearing went out,,,, trashing my fan, shroud and radiator. I had a 4 core. 
Should I stay with the 4 Core rad, factory fan w/clutch and factory shroud?
I have a 400 AT with A/C.
I have heard 3 core is more efficient...

Any recommendations is appreciated.

thanks, 
rick


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## mbergin (Jun 19, 2012)

I had a 3 core and she would run about 215. I changed out to a 4 core and problem solved. I think a 3 core would only be more efficient if it was aluminum as it would dissipate the heat faster. Just my .02


Sent from AutoGuide.com App


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## gjones (Oct 8, 2012)

*Core of the matter...*

EGAD!!! What brand water pump did you have, and did it have the cast or stamped impeller? How old was it? And did you find the cause of it failing? I had a very unfortunate incident with my four core original, and went with an aluminum 3 core - solely because the adverts extolled the virtues of the 3 core aluminum - 30-40% more efficient than a stock 4 core. Seems to be keeping up alright, but I've always have this nagging voice in the back of my head (*ahem*) that keeps telling me (screaming, rather) that I should have stayed with the 4 core. If I had to do it again (probably will anyway), I'd definitely go with a 4 core.


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## ALKYGTO (Mar 29, 2010)

Consider a two core aluminum radiator. Lighter and more efficient. It has larger tubes than the copper. 

I've had great luck with mine and if you get one with stamped tanks it is cheaper and you can fog it black if you like to look "stock".

Check with Afco for an inexpensive one or you can get the more expensive type with fabricated tanks.


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## geeteeohguy (Feb 2, 2008)

If you stay stock, stay with a 4 core. It's an upgrade over the standard 3 core radiator. 3 cores are not more efficient, unless they are aluminum.


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## gr868 (Jul 29, 2013)

Hello everyone,
The pump was from Autozone. Not sure completely, but I think I have the stamped impeller. It looks pressed on. If that's what you mean.
It lasted 12 miles. 
I ordered one from NAPA and should be in today sometime.
A buddy of mine owns a body a body shop and I can get some items at cost.
I got from him a new 2 core aluminum radiator with plastic sides. (Made in China) Good news is that is only $125. 
I am really hesitant though. 
I had a 4 core traditional in there. I don't care if its traditional or aluminum.
Any more advice would be great. 
thanks


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## the65gto (Oct 9, 2008)

gr868 said:


> Hello everyone,
> The pump was from Autozone. Not sure completely, but I think I have the stamped impeller. It looks pressed on. If that's what you mean.
> It lasted 12 miles.


What does Autozone say about this failure. They should have insurance to cover the damage, 12 miles!!!


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## gr868 (Jul 29, 2013)

The District Manager was supposed to call me yesterday. "riiiiight!"
The store manger is going to help me place the claim tomorrow.
I just picked up the new water pump from NAPA. I now know the difference. The NAPA is a cast impeller and much beefier. The AutoZone is a POS compared to NAPA's.
So another lesson learned. NO hard parts from AZ!


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## rvp986 (Sep 19, 2012)

4 core. I would be a little skeptical to run anything less with AC and AT. Try getting rid of the old fan and fan clutch and replacing it with a Flex-a-lite Stainless Steel Blade Flex Fan with spacer. I did a frame off rebuild/restore from the ground up and had a bent fan and iffy clutch. Thought I'd give it a whirl. I love it and have had no problems, unless you want to stay stock. Shop around a little more. You can buy a 4 core for a fair price if you look hard enough.


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## gr868 (Jul 29, 2013)

Thanks rvp986!


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## geeteeohguy (Feb 2, 2008)

I don't do business with AutoZone. Can't stand the place.


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## ALKYGTO (Mar 29, 2010)

gr868 said:


> A buddy of mine owns a body a body shop and I can get some items at cost.
> I got from him a new 2 core aluminum radiator with plastic sides. *(Made in China)* Good news is that is only $125.
> I am really hesitant though.
> I had a 4 core traditional in there. I don't care if its traditional or aluminum.
> ...


Don't put Chinese parts on your AMERICAN car. :cheers

Autozone has a great selection of air fresheners, not much else there for me.


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## skurfan (Sep 19, 2012)

Autozone has so much turnover here that you rarely ever talk to he same person as you did last week. They should pay you for your repairs and labor. Not sure how cooperative they will be since you got the next one from NAPA, but who could blame you for that?


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## chuckha62 (Apr 5, 2010)

I'll chime in here as well... In general, when we deviate from what GM did, we're taking a step backwards. Afterall, they had to warranty what they sold and they pumped more money into R&D, than the aftermarket ever will. 

While I grant you that aluminum is thermally more efficient, it's a given that an aluminum radiator will not last as long as the copper that you replace. Aluminum is far more prone to electrolysis, as well.


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## gr868 (Jul 29, 2013)

All back together. I installed a new 2 core aluminum (That can easily return). It runs about 195 side streets. I just ran the highway and it got to 206. This is without the A/C running. I have not charged the new compressor yet.
My gut is telling me to change.
Option1:
Year One has special on an original for $350 ($100 off). 
Option 2:
Champion has aluminums: 3 row @ $220 or 4 Row @ $280


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## gjones (Oct 8, 2012)

*Ah, but can it core -a- apple?*

They actually have an original? Is that 4 core or 3 core? If it's 4, then you might want to go with that, seeing as how you're going to run a/c. Once that kicks in, you're going to be running even hotter! Be aware that the tubing will likely be smaller, so your cooling system wants to be SUPER CLEAN, so as not to block the tubes. Were you able to look at the condition of the original tubes-clean or cruddy?! Did you set the divider plate clearance on the water pump properly? Oh, and did you get a stamped or cast iron impeller on the pump?


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## geeteeohguy (Feb 2, 2008)

I'll side with my fellow Californian Chucka62 here, and add something: aftermarket flex fans work, but are very noisy all the time. factory clutch fans with a good clutch (like a Hayden_ work extremely well, and are quiet and fuel efficient. I pulled the screaming flex-a-lite off my '65 GTO 3 years ago and went back to factory, and am delighted. Now I can hear the cam and exhaust, instead of sounding like a garbage truck. Factory flex fans are great, and quiet, but hard to find. I scored a 7 blade 18" GM flex fan off of a junked '69 Caddy about 20 years ago, and I love it: cool and quiet. Pulls a TON of air at low speeds.


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## geeteeohguy (Feb 2, 2008)

I was in a hurry (again) and need to clarify: I have the Caddy flex fan on my '67, and a 19" oem clutch fan with hayden clutch on the '65. Both cars run shrouds, which make about a 15-20 degree difference in Fresno in the summer months.


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## Bensjammin66 (May 12, 2009)

I said wow after reading that his 2 row aluminum still got 200+ on the highway! I have an aluminum summit brand 2 row rad with 1" tubing and a 15" syclone fan from flex a lite that kicks on at 190 and off at 165. $250 for the whole setup. I have no hood insulation but i do run a pretty hot cam in my 455 and idle around 750-850rpm. I have never seen temps above 195 even in 90 degree summer day traffic. 

I'd hate to state the obvious here but id start looking to replace the water pump and thermostat. My stat opens at 160 i believe.


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## gjones (Oct 8, 2012)

*8/11 bolt pattern?*

If he does have the old 8 bolt style timing cover, does he still need to set the divider plate, or is that strictly for the 11 bolt pattern style only?


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## gr868 (Jul 29, 2013)

Tried the 2 core. It runs about 210 on a 85 degree day with A/C going and in moderate traffic. 
That seems a little high and think I should go with more cores.
What do you think?


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## BearGFR (Aug 25, 2008)

Whle you're at it, gr868, avail yourself of the forum search tools here. There are several discussions in various places on the forum that cover the topic of how to make your Pontiac's cooling system work very well.

Bear


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## gr868 (Jul 29, 2013)

Thanks Bear.
'will do.


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## joelau27 (Sep 22, 2018)

Get a pump with the cast impeller, and check clearance between impeller and divider plate. Try Ames Perf., BOP,or Butler Eng.


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## joelau27 (Sep 22, 2018)

Use a 160 thermostat, I have a '69 and it never gets to 200. It might get to 185.

Joe


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## bigD (Jul 21, 2016)

gr868 said:


> Tried the 2 core. It runs about 210 on a 85 degree day with A/C going and in moderate traffic.
> That seems a little high and think I should go with more cores.
> What do you think?


A 2-row needs to have at least 1" wide tubes. The cheap 2-rows have smaller tubes. 

Champion makes 2-rows with 1" tubes, under their American Eagle brand name. They're sold direct, on Ebay, and from lots of other vendors. 

https://www.championradiators.com/page/American-Eagle-radiators-shrouds


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