Air induction; hood scoops

[Supercharged111]

2500 radiator is taller, not thicker. 3500 radiator is taller and thicker.

 

[stutaeng]

You can check thermostat by dropping it in a pot of boiling water. It will open slowly and you can see it.

I had one fail on my 4.3 in the winter and truck never warmed up. So I think it's safe to think if it fails in the summer, then engine won't overheat? I forget what's a closed vs open thermostat, someone please chime in.

Is there fail-safe thermostat? Maybe that's OP's upgrade. They are like $10.

Honestly, I'd be more concerned about blowing a radiator hose in the summer, along with blowing a tire...I always see vehicles around the summer on the side of the roads with blown tires, especially them chicom ones on huge, flashy rims... LOL.

 

[stutaeng]

Agreed. The 454 radiator is also taller (I didn't think it was thicker, but ok). The larger radiator will need a new shroud, and brackets.



The opposite is my understanding. Possibly some early HDs were 350's but most of them are swaps. Typically they are 454s or 6.5L diesels. 2001 and 2002's were 6.5's or 8.1's. The 3500 radiator has a taller filler neck that woun't fit under the hood of a pickup. I don't think the core is any larger any way. I don't know what the 8.1 radiator is like, but I think the diesel uses larger hoses.

Ok, I may be wrong about 7.4 radiator being thicker, but definitely "larger."

As far as 5.7s in 3500HDs, I've seen plenty for sale in my area in in the '96-'00 generation, with auto and manual transmission option.

If radiator doesn't fit, then it doesn't matter, but maybe filler neck was just for filling radiator in deeper engine bay, so likely same core, as you suggest.

Thanks for your input.

 

[454cid]

Ok, I may be wrong about 7.4 radiator being thicker, but definitely "larger."

I'm not saying you're wrong about it being thicker..... I've never owned a small block.

 

[Pinger]

Intake inside is gonna be LOUD. If you do use a cowl or a scoop to feed the engine, make sure that's its only purpose. Running an open cowl good to "cool" the engine bay will do the opposite, it'll stall airflow across the radiator. Just get a tune from Blackbeard, toss the throttle body lip,and get a decent flowing exhaust on that thing if you want to boost performance.

Is that the lip on the butterfly edge? Even if not - what is its purpose?

The factory inlet at the core support supplies fresh, cool air to the engine and, at highway speeds, that location is likely a (relatively) high pressure area. The fender plumbing may be a little restrictive, but only above 3000 RPM.

Thinking back to when I was working at the front of my truck (when photo was taken) I think I took a squint into that 'hole' and didn't deduce that was the air feed to the air box as it didn't seem to lead towards it. I guess though that that's what it must be and that GM must have given it some thought.
Isn't it a bit vulnerable to water ingress during fording? Or is it expected that a snorkel would be used if fording was the intention?

 

[Schurkey]

I had one fail on my 4.3 in the winter and truck never warmed up. So I think it's safe to think if it fails in the summer, then engine won't overheat? I forget what's a closed vs open thermostat, someone please chime in.

Thermostats can fail "closed" and the engine overheats. Thermostats can fail "open" and the engine never warms up. Either one is an engine-killing disaster if it's not corrected--but the engine dies quicker if the thermostat won't open.

Is there fail-safe thermostat? Maybe that's OP's upgrade. They are like $10.

There is a thermostat marketed that will lock open if the engine overheats for SOME OTHER REASON. It's a pointless waste of time, money, effort, and enthusiasm. There is no thermostat on Earth that is guaranteed to fail in the open position. That's the nature of "failure"; an unpredictable outcome that can only be reduced, not eliminated.

Honestly, I'd be more concerned about blowing a radiator hose in the summer, along with blowing a tire...I always see vehicles around the summer on the side of the roads with blown tires, especially them chicom ones on huge, flashy rims... LOL.

There's no limit to the amount of stuff the ChiComs can screw up.

 

[Donald Mitchell]

Is that the lip on the butterfly edge? Even if not - what is its purpose?



Thinking back to when I was working at the front of my truck (when photo was taken) I think I took a squint into that 'hole' and didn't deduce that was the air feed to the air box as it didn't seem to lead towards it. I guess though that that's what it must be and that GM must have given it some thought.
Isn't it a bit vulnerable to water ingress during fording? Or is it expected that a snorkel would be used if fording was the intention?

 

[Donald Mitchell]

Is that the lip on the butterfly edge? Even if not - what is its purpose?



Thinking back to when I was working at the front of my truck (when photo was taken) I think I took a squint into that 'hole' and didn't deduce that was the air feed to the air box as it didn't seem to lead towards it. I guess though that that's what it must be and that GM must have given it some thought.
Isn't it a bit vulnerable to water ingress during fording? Or is it expected that a snorkel would be used if fording was the intention?

It turns up to the top of the fender so not much chance of rain getting in.

 

[someotherguy]

Maybe compare cooling system to 3500HDs GMT 400. Those trucks were like GVWR of 15,000 lbs, and a lot of them were equipped with 5.7s.

I agree with pretty much everything in your post except for that. The overwhelming majority of 3500HD's were 6.5td and 7.4. Very, very few were factory-equipped 5.7's as evidenced by the engine code on the VIN, and those were just in the first couple years of the model.

A wider, thicker radiator meant for a heavier 400 with a 7.4 would be a great way to keep the engine cool, though. Just don't buy one for a 3500HD because it literally won't fit - the core support is taller on those trucks by a couple inches and the filler neck for the radiator is extended to match. And, the 6.5td radiators won't work either because the filler neck is relocated to the reservoir like a GMT800-newer.

Richard

 

[PlayingWithTBI]

A wider, thicker radiator meant for a heavier 400 with a 7.4 would be a great way to keep the engine cool, though

Won't you have to change/modify the core support for the wider 7.4L radiator?

Edit: And the fan shroud?