# new radiator help



## dgoat8u (Jan 10, 2011)

Well, i have decided to buy a new radiator, to see if it will help win my over-heating battle. I really want to keep the original look, not a polished Be cool or anything. OPGI has some original looking 4-rows, but they are not aluminum. From what i hear, the 4-row will be better than my original, but the all aluminum would be the best. Has anyone got a 4-row from OPGI? And did it work good? Thanks!


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## JustAl (Mar 20, 2010)

Check out the U.S. Radiator web site. They make many of the radiators sold through the restoration suppliers sites. I called them and their recommendation was not aluminum but rather a "high efficiency" copper model. They claim it out cools their own aluminum model and is repairable whereas the aluminum are not. You didn't mention what year you have, or core size, but when I replaced the radiator on my 65 GTO, I modified the core support to accommodate an AC style radiator which gives 2 inches of height increase. It was a non-air car to start.


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## kjk990 (Sep 1, 2010)

I have a 67 GTO. I just had the engine rebuilt, 4 core radiator that is probably 20 yrs old, rodded and cleaned. On an 80 degree day driving I would run about 210-215. If I stopped or got stuck in traffic I would get up over 235.

I bought an aluminum radiator of Ebay for $200.00. On an 80 degree day I run at 182 (I have a 180 thermostat). If I sit for 15 minutes or so I would get up to about 220. So I installed a auxiliary electric fan to push air through the radiator when I'm stopped. Now it runs at 190 when I'm stopped. Doesn't matter how long, 190 degrees. 

Check out this article. I found it very interesting. good luck.

Cap-A-Radiator


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## Eric Animal (Oct 28, 2007)

I have a GRIFFIN also (like in the Cap-a-Radiator article)....haven't run it yet. I bought the 1.5 inch 2 row model.....


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## BearGFR (Aug 25, 2008)

Have you properly adjusted the clearance between your water pump impeller and the plate that goes behind it? That can make a HUGE difference in how well your cooling system works. If that's "off", no radiator is going to help you much.

Bear


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## kjk990 (Sep 1, 2010)

I agree with Bear. Check the pump plate clearance and make sure both short pipes are win place with gaskets. When I first worm up the car I look in through the radiator cap hole, when it hits 180 degrees and the thermostat opens you can see the water moving. After I fixed my plate the water movement was much more violent. It lowered my temp some but I still ran hot.

Have you had your current radiator rodded? it usually runs about $100-$125. This will clear out any blockages and increase cooling. 

Good luck


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## triplets (Apr 7, 2011)

Can someone alaberate on this water pump shiming,I Have a 3 core rad non ac on my 65 gto that has been roded. Im running a consistent 225 with a ele fan that does nothing .I was concidering a 4 row rad myself.I checked my manual it says nothing about plate clearance?


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## kjk990 (Sep 1, 2010)

This youtube video shows how to do it.


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## Eric Animal (Oct 28, 2007)

:agree......very important for pump efficiency!


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## Chris-Austria (Dec 23, 2010)

I've done it too like Bear told me.. and now the temp of my 66 GTO is a lot better. I also changed the old pump to a new aluminum pump and now I'm using a high flow thermostat. These 2 changes and the plate on the right position gave me 190° on hot summer days instead of 220° and on colder days it runs at 160-180° with my 160° thermostat.


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## jigaway (Jul 2, 2011)

Does running a clutch type fan improve cooling significantly over a "flex" fan?? I can hear my coolant gurgling in the block which seems odd since I went to a flex fan..

Thanks in advance,

Dan


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## BearGFR (Aug 25, 2008)

jigaway said:


> Does running a clutch type fan improve cooling significantly over a "flex" fan?? I can hear my coolant gurgling in the block which seems odd since I went to a flex fan..


It sure can, if it's a good quality fan and clutch. One of the purposes of the clutch is to make sure the fan doesn't spin faster than it's optimum rpm. That's where it's most efficient and moves the most air. It's quite possible to spin a fan too fast. The tips of the fan blades can actually go supersonic, and the fan get's so inefficient that it acts more like a flat plate that BLOCKS air flow instead of promoting it.

If you want to keep your Pontiac nice and cool, here are the steps (pretty much in priority order)
1) Proper clearance on the water pump plate
2) Good fan, clutch, and fan shroud, properly installed
3) Good pump
4) Factory radiator, clean and clear (no corrosion or blockage)
5) Increased cooling capacity radiator

Usually on stock or close to stock engines, you'll be cruising in Cool City by the time you get to 3) or 4). 5) Is usually needed only in extreme circumstances, like much higher than stock horsepower applications and/or extreme climates.

That's my story and I'm sticking too it. 

Bear


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## jigaway (Jul 2, 2011)

Many thanks Bear for a concise list.. Something just isn't right with mine. I'm gonna start at the top of your list and then put back on the clutch fan.


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## Chris Holabaugh (Jan 18, 2009)

On my 462 making 500+hp I had put a high volume water pump on the engine, but it still ran hot with stock radiator. So I purchased a Rodney Red aluminum radiator and just painted it black. I put it in with a clutch fan and stock shroud and temps have been 185. With the black paint the whole thing just looks stock and works great.


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## Chris-Austria (Dec 23, 2010)

I also believe my temps got a little better after setting the ignition timing from 10° to 7°... maybe you can check if your timing is correct!


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## triplets (Apr 7, 2011)

Thank you so much. i ordered a new gasket to check mine.


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## triplets (Apr 7, 2011)

Thank you so much.I ordered a new gasket to check mine.


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## jigaway (Jul 2, 2011)

Figured out something this morning that may be the cause of my overheating. I bought a replacement radiator that was not "Heavy duty". My resto guy said he wondered about it's ability because it is smaller and has less/more chambers?? Apparently if your engine is hopped up like mine, racing heads, cam, bored 0.3, you might not should have a wee radiator!! Duh..
I thought I was doing the right thing by getting a new one. Thankfully my old one, which isn't so old, is a major heavy duty radiator and the resto guy has it sitting in his shop. I'll slap it back in tonight. Thanks again for the advice.

Dan


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## BearGFR (Aug 25, 2008)

Yep, capacity matters 

It's still worth the effort to clearance the pump properly. That made a significant difference on my car, even with a big alumunim radiator and twin electric fans. I was surprised at how much difference it made.

Bear


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## Eric Animal (Oct 28, 2007)

check out a Hayden heavy duty fan clutch and a 19" stock fan.....Bear's first post on this thread is most correct....and don't forget a shroud. E


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## pontiac (Mar 6, 2011)

67 factory timing cover does not have the two tubes and rubber rings like the later 
69+ model covers.


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## old66tiger (Nov 2, 2011)

Mark 7 makes a nice unit. Expensive, but nice


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