Radiators and Air Conditioning, What should I do?

mpro69rr

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Hey Guys,

69 RR 383 built pretty good. I have been reading a lot on radiators and AC, and what I have, 22 inch, is not going to cut it with AC. When its not to hot out I stay at 180 and it goes up when I stop at lights, I live in FL and its getting real hot. I am going to have to do something different but I don't know which option to go with? Please see my options below:

1. Go with US Radiator 22 inch optima tripleflow 4 rows. Its supposed to radiate 40% more heat. Found this one in a motortrend article. see Mopars Need Extra Help With The Heat—Here’s How To Fix It!
Plymouth Road Runner, 1966-69 383 / 426 Hemi Radiator - US Radiator

2. Go with US Radiator 26 inch that fits a 22 inch core, this would also be optima tripleflow 4 rows.
Plymouth Road Runner, 1966-69 Radiator - US Radiator

3. Another way I could go is putting in a new passenger side support and go with the 26 inch radiator. I would have to have a body shop do this option and it would probably cost a lot. Motortrend article on this too.
Upgrade Your Mopar’s Core Support to 26 Inches & Get Cooled!
1966-1970 DODGE & PLYMOUTH B-BODY RADIATOR SUPPORT EXTENSION

This sucks because I already bought a wizard 22 inch radiator and would have to eat the cost. But I also already bought classic air and I don't want to eat the cost for that! I really need help on this, which option should I go with? Thanks Guys!
 
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451Mopar

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You need good airflow through the radiator.
On my '69 Coronet convertible, I was using a 26" 4-core radiator and Ford Contour electric fans and that was OK until I added the A/C.
A mechanical fan would have been better, but with the serpentine belt system, there was not much room between the pulleys and radiator.
I found that the thicker 4-core (0.63" tubes) radiator is really thick making it harder for air the flow through the radiator.
I am trying a 2-core (1" cores) radiator (Griffen) that is about 1" thinner than the 4-core, and adding dual 13" cooling fans.
No results yet, still wiring the EFI on the car, but it looks like it should cool better than the prior setup.

Before I put the serpentine belt system on, I had the Mopar Viscous cooling fan package, and a Glen-ray radiator, and it worked good.
No A/C at the time, but I think it would have handled it?
 

davek

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just a heads up,when you go to an after market radiator you will probably end up changing your fan setup do to less room between WP and radiator. A member hear sold me brackets to go from 22 to 26 radiator . I bought a ColdCase radiator. Could not use my stock fan setup.
 

mpro69rr

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Any other opinions? Does anyone know how much more heat AC adds?
 

Demonic

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You have a new-ish 22" radiator and it goes up at lights? How is the existing shroud? If you were at a steady 180 I wouldn't worry about it. Use a high flow thermostat. Maybe fix the temperature creep at stop and go traffic and stick with the 22". Less cost, you can always upgrade the radiator later.
 

mpro69rr

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You have a new-ish 22" radiator and it goes up at lights? How is the existing shroud? If you were at a steady 180 I wouldn't worry about it. Use a high flow thermostat. Maybe fix the temperature creep at stop and go traffic and stick with the 22". Less cost, you can always upgrade the radiator later.
Existing shroud is ok but has a lot of leaks around it. I had it custom made but had to do some modifications to it, didn't fit right. I don't know how to fix the leaking air through the side and bottom. I will try a high flow thermostat and see what that does. Thanks for the reply!
 

69hemibeep

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Its pretty easy to open the support up on the passenger side for a 26". Bent a new lip touched the paint up on my daughters charger, can't hardly tell when put together
 

mpro69rr

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Its pretty easy to open the support up on the passenger side for a 26". Bent a new lip touched the paint up on my daughters charger, can't hardly tell when put together

Yes, I am thinking about that option too.
 

hunt2elk

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I have switched over to full flow thermostats along with FlowKooler water pumps. Not a drastic difference, but it is noticeable. Every little bit helps, right?
 

mpro69rr

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I have switched over to full flow thermostats along with FlowKooler water pumps. Not a drastic difference, but it is noticeable. Every little bit helps, right?

Yes, true, every little bit helps! I can't remember if I put a high flow water pump in but I will pick up a full flow thermostat. Hopefully that will get me at least a little bit closer. Thanks!
 

1967coronet

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One thing is the AC condenser cuts down air flow at idle and road speed both.
A good factory style shroud along with a 18 " clutch fan.
Just me but I would purchase a good 10 to 12" electric pusher fan .
Wire it into the AC power with its own relay so once you flip the AC on the pusher runs also.
Ac or ignition shuts off so does the fan.
 

Nxcoupe

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I would absolutely go with the 26" rad and just modify your current opening and use nuts and bolts on the pass side. You'll need the airflow for the condensor and the increased heat load. If you are already creeping at stoplights, ac is going to make it worse. A lot worse.
A high flow water pump actually moves the coolant faster through the radiator not allowing it time to dissapate its heat. Jmho
 

mpro69rr

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I would absolutely go with the 26" rad and just modify your current opening and use nuts and bolts on the pass side. You'll need the airflow for the condensor and the increased heat load. If you are already creeping at stoplights, ac is going to make it worse. A lot worse.
A high flow water pump actually moves the coolant faster through the radiator not allowing it time to dissapate its heat. Jmho

That's what I'm thinking, 1967coronet had a good point that I will get a reduced air flow with the condenser. I think I will need as much air flow as possible with the AC. I'm going to look into how much the right rad support will cost, I just don't have enough experience to start cutting. Thanks!
 

mpro69rr

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One question I do have is if I go with a new right rad support will the new 26" radiator be in the stock location for a shroud?
 

68 Sport Satellite

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I've been down this same road. Started with a 318 and 22" rad on my 68 B body Satellite. I tried to make the 22" work, even tried a 22" extra thick (3") Griffin rad. It worked until I swapped in the big block. I'm adding A/C now. 26" rad was the only way.

-Enlarged opening to 26" towards passenger side and fastened with drilled nuts/bolts.
-Replaced radiator with Griffin Exact fit 26" aluminum (2 row x 1-1/4" tube diameter).
-Added stock 26" plastic shroud.
-Make sure fan is half inside shroud for proper radiator spacing. I had custom thickness fan spacer made.
-Used high flow Milodon T-stat. When you see the T-stat flow opening you will notice how much more flow there is here.
-Fixed fan stock 18" 7-blade (this thing cools WAY better than any electric fan setup I've seen).
-Water pump upgrade. Started with assumption that slower flow is better and went with the old stock big block 6 blade water pump. I've since learned that faster flow cools better and have a Flowkooler water pump now. I imagine an 8-blade water pump may also work ok.
-50/50 coolant/water mix filled to 2" from top of rad neck.
-New upper/lower hoses to ensure no collapsing.
-Proper tune on motor (a too lean motor can cause overheating).

This is all with a full 26" width aftermarket condenser in front of the radiator. (Rest of A/C install still in progress).

Others are having good success with copper tube 26" radiators. I really think in your case a 26" rad is a must. However, remember that the rad needs all of the other cooling parts mentioned above to work the best.

Also, double-check your coolant temp gauge. I was originally going off of the stock gauge and after several years my coolant temp was showing super hot. It turned out I had fried my cluster temp gauge due to running too high voltage and it wasn't accurate. It would especially go hot with applied throttle. I swapped in an analog temp gauge and found out my motor was not running as hot as I had thought. I also swapped in a voltage regulator with adjustable pot on back to compensate for my aftermarket 70A alternator.

Good luck:)
 

mpro69rr

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I've been down this same road. Started with a 318 and 22" rad on my 68 B body Satellite. I tried to make the 22" work, even tried a 22" extra thick (3") Griffin rad. It worked until I swapped in the big block. I'm adding A/C now. 26" rad was the only way.

-Enlarged opening to 26" towards passenger side and fastened with drilled nuts/bolts.
-Replaced radiator with Griffin Exact fit 26" aluminum (2 row x 1-1/4" tube diameter).
-Added stock 26" plastic shroud.
-Make sure fan is half inside shroud for proper radiator spacing. I had custom thickness fan spacer made.
-Used high flow Milodon T-stat. When you see the T-stat flow opening you will notice how much more flow there is here.
-Fixed fan stock 18" 7-blade (this thing cools WAY better than any electric fan setup I've seen).
-Water pump upgrade. Started with assumption that slower flow is better and went with the old stock big block 6 blade water pump. I've since learned that faster flow cools better and have a Flowkooler water pump now. I imagine an 8-blade water pump may also work ok.
-50/50 coolant/water mix filled to 2" from top of rad neck.
-New upper/lower hoses to ensure no collapsing.
-Proper tune on motor (a too lean motor can cause overheating).

This is all with a full 26" width aftermarket condenser in front of the radiator. (Rest of A/C install still in progress).

Others are having good success with copper tube 26" radiators. I really think in your case a 26" rad is a must. However, remember that the rad needs all of the other cooling parts mentioned above to work the best.

Also, double-check your coolant temp gauge. I was originally going off of the stock gauge and after several years my coolant temp was showing super hot. It turned out I had fried my cluster temp gauge due to running too high voltage and it wasn't accurate. It would especially go hot with applied throttle. I swapped in an analog temp gauge and found out my motor was not running as hot as I had thought. I also swapped in a voltage regulator with adjustable pot on back to compensate for my aftermarket 70A alternator.

Good luck:)

Thanks, this is what I'm looking for! Did you have any problems fitting the stock fan shroud? How hard was cutting the rad support and what did you use? Maybe I will try it, I just got back in from the garage and was looking at it, trying to figure out if I could do it. I just looked at griffen and they have 25.5 inch not 26 inch, does that make a difference?
 
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Nxcoupe

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Thanks, this is what I'm looking for! Did you have any problems fitting the stock fan shroud? How hard was cutting the rad support and what did you use? Maybe I will try it, I just got back in from the garage and was looking at it, trying to figure out if I could do it. I just looked at griffen and they have 25.5 inch not 26 inch, does that make a difference?
Ebay has dozens, but there is only one place that has a factory looking aluminum radiator, and unfortunately, they don't have any big block tanks right now.
The way I would do it, is remove the grille and bumper, and anything else blocking the core support, and then mount the new 26" radiator in using the driver's side mounting points. Screw the hardware in and make sure radiator is level and tighten it down. Next, mark and drill the passenger side mounting holes.
Remove the radiator and now you can sketch where to cut out the passenger side. Just match the existing contour but over 4 inches. You don't need to bevel the edge or anything it'll work as is.
Good luck.
 

mpro69rr

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Ebay has dozens, but there is only one place that has a factory looking aluminum radiator, and unfortunately, they don't have any big block tanks right now.
The way I would do it, is remove the grille and bumper, and anything else blocking the core support, and then mount the new 26" radiator in using the driver's side mounting points. Screw the hardware in and make sure radiator is level and tighten it down. Next, mark and drill the passenger side mounting holes.
Remove the radiator and now you can sketch where to cut out the passenger side. Just match the existing contour but over 4 inches. You don't need to bevel the edge or anything it'll work as is.
Good luck.

Thanks Nxcoupe, you have been very helpful!
 

68 Sport Satellite

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Thanks, this is what I'm looking for! Did you have any problems fitting the stock fan shroud? How hard was cutting the rad support and what did you use? Maybe I will try it, I just got back in from the garage and was looking at it, trying to figure out if I could do it. I just looked at griffen and they have 25.5 inch not 26 inch, does that make a difference?
I did not remove my bumper when cutting the passenger side to widen the rad opening, only the grille.

I used a small circular cutting saw with a bi-metal blade. Hand filed the sharp edges after cutting. Drilled holes and used nuts and bolts to mount the passenger side. I ordered this Griffin Exact fit rad. It's 25.5" wide. I like that the stamped top looks OEM. I sprayed mine black top/bottom and front/rear faces using 2 different black products.
Griffin Thermal Products 5-70004 Griffin Exact Fit Radiators | Summit Racing

I bought the plastic shroud to fit from Summit and had no issues mounting it.
Mopar Performance P2785434 Mopar Performance Restoration Radiator Cooling Fan Shrouds | Summit Racing
 

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