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Aluminum vs Copper radiator

Chris Ziemer

Chris Ziemer

Daily Driver
 Premium
Joined
Jun 8, 2022
Posts
151
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131
Location
Galt CA
Hi all, looking for input on radiators. I’m in Northern California and running in 100 plus degree weather.
Currently have a Chinese 4 row aluminum (not sure of tube size) with my full size AC condenser and 9” trans cooler in front of that.
With no AC, it runs 190 pretty stably (160 thermostat), but with the AC on and idle, it creeps up to 210 and beyond. Not sure where it’s stop. And the truck does not easily recover once back on the freeway.
Stock 7 blade fan with stock shroud with stock fan clutch.

I got such mixed reviews from the people I’ve talked to, I thought I’d reach out. Is it better to have an aluminum three row with 1 inch tubes or a four row brass and copper traditional half-inch tubes? I mean the coolant can only go as fast as it can through the thermostat so I’m not sure how much tube size matters (not what she said).

Anybody running in hot weather with AC? My goal is to be able to idle on 100° heat with my AC on.

Thanks!
Chris
 
Are ya certain that the fan clutch is working properly ?

For the most part either type of radiator type will get the job done assuming they’re enough capacity and in good working order.

Also, ya may want to get that trans cooler out from in front of the A/C condenser - major help in A/C effect - won’t necessarily hurt engine cooling but still doesn’t need to be there.
 
Thank you!

I’ll check the fan clutch again tomorrow. Seems like it was harder to spend when warm than it was when it was cool. But it’s an old clutch I’m sure. So I guess I’m not really sure it’s working effectively. Fan clutches another issue for me. They talk about heavy duty fan clutches, I saw one on the forum here about one from a Dually 454 that was supposed to fit, but couldn’t find a link or find it on the web.

The champion radiator is supposed to cool 1000 horse which I may end up going to. But it doesn’t say it cools 1000 horse with 27 different radiators in front of the radiator.

No matter what, I’ll see about moving that transmission cooler somewhere.
 
Chris Ziemer said:
I saw one on the forum here about one from a Dually 454 that was supposed to fit, but couldn’t find a link or find it on the web.
Click to expand...

:rotfl: If you read that here or on gmsquarebody.com then the dually reference was 99% about @tarussell old truck. He figured out the magic recipe from that truck’s original set up, I used it on my old K10 and it cooled amazingly well (but no a/c).
 
kennyw said:
Overheating at idle, but not at highway speeds, is more likely an airflow issue than a water flow issue.
Click to expand...
That makes sense. Move the trans cooler and install a pusher fan? The darn AC condenser is so big. Covers entire opening. Not sure if there is anything to be done with that.
 
Chris my 77 has a big 4 row brass radiator, higher fin per inch count, running dual ac original condenser. I ran cool with a 19" 6 blade, severe duty clutch, almost stock shroud. Here in Havasu 100° is our low, and worked great. Last winter I messed around with my timing and ended up running @20°. Summer rolls around and I have the same issue you describe. I thought at first the latest fan clutch from chain auto parts had laid down. So I got several more, and different blades. None of them helped much. Turning off the ac the truck would run cool even long idles. I had a 10" pusher on the condenser, runs any time the compressor clutch is engaged.

I am now thinking the 20° advance at idle is probably the change that makes it run hot low speeds and idle. Do your self a favor and check your timing.

I wanted to stay with a mechanical fan and resisted electric for a long time. Last year on way home from BB24 truck got hot 2 block from the house. I drove to and from Moab, the last 2 miles were the only miles I wasn't driving 55 plus. I figure the little bit of frame twisting I did at Moab caused the fan to rub on the shroud and damaged the clutch.
Now I am preparing to go with the windstar fans. If you wheel your truck at all you should plan on electric puller fans. Skip the pusher go full electric.

My thinking, if you have an all cast iron engine, you can run brass rad and heater. if you have iron, and aluminum eng, run aluminum rad and heater.
 
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For an old school H.D. ( actually a Severe-Duty ) fan clutch use a ‘81~’88 K30 454 optional Severe-Duty Cab Chassis application - years ago there was a different part number for a very effective fan clutch that was made for trucks equipped with a high numerical gear ratio ( stayed engaged longer even at higher RPM’s ) but as time passed by they now have superseded the part numbers and choices down to just a few options.
A clutch like this will pull a bunch of air at idle - try this before you go through the trouble of a pusher fan.

As Wes’s says - if you ever go with electric puller fans the Windstar stuff is far more reliable / durable than a lot of aftermarket ones.
 
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I’ve had really positive results from changing to a proform high flow aluminum water pump. Running a 205 thermostat, and the temps are about the same, but when trail riding/idling around town it’s able to still close and cycle the thermostat (have mechanical water temp and oil pressure). I also see less heat soak via higher (about 10psi) warm engine oil pressure (indicating lower oil temps). Paired with a Hayden 2797 fan clutch. Any reason not to bump up the thermostat to give the coolant some dwell time in the radiator? That’s always been my concern with low temp stats at least.

Oh, and big brass radiator but I’ve had that for years and it was fun until crawling along the trails.
 
Wes Harden said:
Chris my 77 has a big 4 row brass radiator, higher fin per inch count, running dual ac original condenser. I ran cool with a 19" 6 blade, severe duty clutch, almost stock shroud. Here in Havasu 100° is our low, and worked great. Last winter I messed around with my timing and ended up running @20°. Summer rolls around and I have the same issue you describe. I thought at first the latest fan clutch from chain auto parts had laid down. So I got several more, and different blades. None of them helped much. Turning off the ac the truck would run cool even long idles. I had a 10" pusher on the condenser, runs any time the compressor clutch is engaged.

I am now thinking the 20° advance at idle is probably the change that makes it run hot low speeds and idle. Do your self a favor and check your timing.

I wanted to stay with a mechanical fan and resisted electric for a long time. Last year on way home from BB24 truck got hot 2 block from the house. I drove to and from Moab, the last 2 miles were the only miles I wasn't driving 55 plus. I figure the little bit of frame twisting I did at Moab caused the fan to rub on the shroud and damaged the clutch.
Now I am preparing to go with the windstar fans. If you wheel your truck at all you should plan on electric puller fans. Skip the pusher go full electric.

My thinking, if you have an all cast iron engine, you can run brass rad and heater. if you have iron, and aluminum eng, run aluminum rad and heater.
Click to expand...
Thanks Wes, that’s a good point on the timing. I actually just put in a new crate 350, but my timing is around 6 lol! I may bump it up to 10 if I’m feeling sporty but wow! I’m definitely in the junior class here.
if I can’t keep it cool, I will switch over to the WinStar fans. I’m not sure how much CFM they pull, but I read that the seven blade pulls somewhere around 5000 CFM. So I guess I kinda wrote off electric fans because so many of them only pull 2, 3 4000 CFM.
But the proof is in the pudding with you guys. They work.
 
tarussell said:
For an old school H.D. ( actually a Severe-Duty ) fan clutch use a ‘81~’88 K30 454 optional Severe-Duty Cab Chassis application - years ago there was a different part number for a very effective fan clutch that was made for trucks equipped with a high numerical gear ratio ( stayed engaged longer even at higher RPM’s ) but as time passed by they now have superseded the part numbers and choices down to just a few options.
A clutch like this will pull a bunch of air at idle - try this before you go through the trouble of a pusher fan.

As Wes’s says - if you ever go with electric puller fans the Windstar stuff is far more reliable / durable than a lot of aftermarket ones.
Click to expand...
Thanks tarussel, I just ordered your severe duty clutch. Seems like the least expensive place to start and should definitely give me way more flow.
 
bigjimmy82 said:
I’ve had really positive results from changing to a proform high flow aluminum water pump. Running a 205 thermostat, and the temps are about the same, but when trail riding/idling around town it’s able to still close and cycle the thermostat (have mechanical water temp and oil pressure). I also see less heat soak via higher (about 10psi) warm engine oil pressure (indicating lower oil temps). Paired with a Hayden 2797 fan clutch. Any reason not to bump up the thermostat to give the coolant some dwell time in the radiator? That’s always been my concern with low temp stats at least.

Oh, and big brass radiator but I’ve had that for years and it was fun until crawling along the trails.
Click to expand...
Thanks bigjimmy82, the local radiator shop said the same thing about the thermostat. I guess it was kind of experimenting. But yes, I have a 180 to put back into it. Good point!

What’s the general consensus on what’s too hot? I don’t even like 205. I’m afraid 205 turns into 230 too quickly if there is a problem. And I’m a little nervous about keeping this new motor cool. I’m running 50-50 Zerex green, so it’s not really a boiling factor, just old ideas I guess.
 
When you start the engine, do you hear the fan roaring? It will with a HD clutch. Is it making a lot of noise when the engine is hot? The fan clutch is a wear item and makes a huge difference in how much air is passing through the radiator.
 
Chris Ziemer said:
That makes sense. Move the trans cooler and install a pusher fan? The darn AC condenser is so big. Covers entire opening. Not sure if there is anything to be done with that.
Click to expand...
1st thing is be sure the fins are clean and your cooling fan and clutch are moving air. These trucks did not overheat from the factory in those conditions, no reason yours should if things are working properly.
 
Blue85 said:
When you start the engine, do you hear the fan roaring? It will with a HD clutch. Is it making a lot of noise when the engine is hot? The fan clutch is a wear item and makes a huge difference in how much air is passing through the radiator.
Click to expand...
Definitely don’t hear any roaring on start up, but really the whole thing is so loud it’s hard to distinguish. Maybe once I put the severe duty on I will be able to isolate that noise better.
 
Chris Ziemer said:
Definitely don’t hear any roaring on start up, but really the whole thing is so loud it’s hard to distinguish. Maybe once I put the severe duty on I will be able to isolate that noise better.
Click to expand...
Yeah I am in norcal too with a 454, in one truck, 350 in the other, both now have the Chinese aluminum radiator, and I don't have a problem idling in the 100 degree weather.
My A/C does warm up a little though because the condenser doesn't get enough cooling but still good enough
 
Another item that changed I should have included in other post, I up sized tires. I had 33's and 4.88 gear last summer. This summer I have 37s and same 4.88, My rpm at low speed is way lower than before. I did try driving around town in second gear and that did help, but not as much as I wanted to see. Also this is over 110° F ambient, 105° and down is not really and issue. Maybe if I left it idling parked form long time with ac on.
 
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