Big Block Swap Cooling

[DTrain]

So I swapped out my factory 350 with a 454 earlier in the year, which has been absolutely awesome.

In the last few weeks though, the weather has been super hot and I’ve been running the AC full blast. I don’t have any issues with running hot unless the AC is on, and mainly while sitting too long with it on.

The radiator was pretty much new when I did the swap, so I kept the factory 350 cooling setup when I did the swap.

When I first noticed the overheating, I swapped the 195 thermostat with a 180, which was helpful. I was still worried about it, so I ordered a severe duty cooling fan and swapped out the fan, which again was somewhat helpful.

I can run all day long with the AC off and don’t have to worry about running hot. Sometimes when I pull it’ll creep up towards the 210 range, but nothing I’ve been worried about yet.

I’ve been doing some researching and learned the big block truck had an aux cooling fan, which mounts in front of the AC condenser. I can order this fan and the wiring needed from RockAuto for about $120. Maybe this is the quick and easy answer to my problem.

I’ve heard folks say that eliminating the cooling fan from the motor and running fully electronic dual fans can actually help out with HP a little bit, but have no experience in this department.

So my few questions are...

Is getting the aux fan that mounts to the AC condenser just quick and easy, or is it the best solution? Is the AC Delco best for this, or is there something better?

Would forgetting the aux fan and ditching the motor mounted cooling fan and finding a good dual fan system be the best solution? If so, what are some good ones to look at? Will I actually gain any performance this way?

Any advice for my situation would be appreciated.

Thanks!

 

[PlayingWithTBI]

The radiator was pretty much new when I did the swap, so I kept the factory 350 cooling setup when I did the swap.

The factory 350 radiator is smaller than the 454s unless you have the towing package, IIRC.

 

[DTrain]

Yeah, I assumed my radiator was smaller. I didn’t want to change all that stuff in the swap to save some money and also it was mostly new. But the issue I’m having seems small enough to be resolved with leaving it in place and introducing fans of some sort. That’s my hope anyways.

 

[DTrain]

It seems even with a different radiator, assuming mine is truly wrong, the big block trucks still had an aux fan.

 

[454cid]

The auxiliary fan doesn't come on until 225F or head pressure in the AC system rises to a certain level. I don't think it's your answer. I question if you actually have any problem if you're only seeing 210F, in Georgia.

If you swapped the thermostat to a cooler one, and you lowered your running temperature, then that indicates your radiator had additional cooling capacity to spare.

 

[DTrain]

So, I did mention 210, when towing and no AC. I guess I failed to mention, 225/230 sitting in traffic with the AC blasting can happen. Cruising I don’t have any issues with the AC going, it’s stop and go that it’ll get above 210.

 

[454cid]

So, I did mention 210, when towing and no AC. I guess I failed to mention, 225/230 sitting in traffic with the AC blasting can happen. Cruising I don’t have any issues with the AC going, it’s stop and go that it’ll get above 210.

Does the AC heat up?

What fan are you running now? You mentioned severe duty... is that an 11 blade plastic/nylon fan? What about the clutch?

If you've got good air flow, you may be down to the bigger radiator. The big block radiator would likely be cheaper and much easier to setup than trying to put together an electric fan system. I've never done it, but from what I've read online over the years is that it's really easy to end up with something that doesn't work as well as a mechanical fan.

 

[L31MaxExpress]

My Tahoe has a 2" body lift. I used an all aluminum 34x19x2.5" core radiator and a matching GMT400 3500HD fan shroud. Used a duramax fan blade on a Trailblazer SS thermal clutch. Keeps the 450 hp 8.1 at 180°F even with the a/c blasting and towing. Without the 2" body lift I would have used the 34x17 radiator and a matching 454 shroud. I kept the stock pusher fan and programmed the 8.1s PCM to turn it on with the A/C with the coolant temp over 85°F under 50 mph or when the coolant hits 190°F. Sitting in traffic with the idle at 750 rpm the a/c blows 40°f. In bumper to bumper traffic the truck sounds like a medium duty truck. When you get rolling again it roars for a about 30 seconds before it goes back to freewheeling.

 

[DTrain]

The AC has heated up a couple times that I can think of, not all the time though.

The fan I’m running is the fan that came with the 454 that was rebuilt that’s in my truck now. It’s a metal, 9 blade fan. The clutch I put on was a Hayden, I ordered it from RockAuto.

 

[Zx1000hd]

I have an 11 blade ac Delco p/n 15-80739 Instead of the 5 blade to my 454 but in the Phoenix heat it's still 225/230 in traffic the aux fan does help. But it does require the right side coolant temp switch not sensor and it is set at 225°.. I also have an 03 c2500 radiator in mine as well.

 

[letitsnow]

I spent a bunch of money once on a powerstroke that was heating up while on a trip out west. Turns out the radiator just needed to be cleaned (carefully) with a power washer. Might be worth a try.