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Speed Holes
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5,190 Posts
Discussion Starter #1
I've got an '02 GMC Sierra with the 5.3.

I'm looking to throw some e-fans on it, but also now thinking about swapping in a 34" radiator (possibly the 3/4 ton radiator, but all depending on price).

Anyway, call me an idiot, but how do I determine if I've got a 34" radiator or not already??
I'm pretty sure my truck should have been equipped with the 28" radiator, but when I measure the dimensions of the radiator it is 34" wide, edge to edge.
So, is the proper measurement from the edge to edge of the fins/fan shroud??? That equals about 28" on mine...
But the entire width of the radiator is 34", that's what boggled my mind. :think:


I should mention, the truck was in an accident involving a deer, and I believe the radiator was replaced at that time, but with which one, I do not know.



So, assuming that I do only have the 28" radiator, what all is involved with swapping in an '05 or newer 34" radiator???


Is it direct bolt in, same bracketry, same hoses as are already on my 2002?

Anyone have a part number for the proper 34" radiator? I don't want to get one of these cheap radiators, preferably the OE.

Any other part #'s I might need to know so I can gather the proper parts?j

Fill me in on the details, info is appreciated!
 

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Speed Holes
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5,190 Posts
Discussion Starter #2
Alright, got a quick answer here!

I've been informed by Hit Man X that no other parts are needed for the swap, it's a direct bolt-in and go swap.
Thanks for the help there Hit Man X.



But, that still leaves me wondering about if I've actually got the 28" radiator??

And also still looking for a solid part # on one of these 34" radiators.

(I've already got a trans cooler, so I don't need the factory option.)
 

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Registered
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1,129 Posts
The 34" radiator is 40" across tip from tip. I checked into the measurements over at performance trucks and thats what they were saying. If your radiator is like mine it is 34" from edge to edge and that means its the 28" one. The radiators are measured by the core only.
 

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resident pyromaniac
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7,498 Posts
Picture304.gif


easiest way of determining...look at the front header panel where the radiator bolts into...all of the front header panels come pre-drilled for the 34" radiator. see the holes that my efans are bolted into? those are the holes that the 28" radiator bolt into...if you have a 28" radiator, yours will be bolted into those holes and the holes where my radiator is bolted into will simply be left open in your header panel...
 

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Speed Holes
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5,190 Posts
Discussion Starter #5
The 34" radiator is 40" across tip from tip. I checked into the measurements over at performance trucks and thats what they were saying. If your radiator is like mine it is 34" from edge to edge and that means its the 28" one. The radiators are measured by the core only.

Gotcha, that's what I was thinking, but wanted to confirm...
(Seems that performance trucks forum has some deep info as well! I might have to join over there one of these days)


So, the part number I'm looking at is AC Delco #: 21650
Core size 34X18.5X1.125

Anyone have an objection?


I see other part numbers for 34" radiators, but most are way more expensive and have other aux. coolers, like trans or oil, which I'm not necessarily looking for at the moment.
 

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Speed Holes
Joined
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5,190 Posts
Discussion Starter #6
Picture304.gif


easiest way of determining...look at the front header panel where the radiator bolts into...all of the front header panels come pre-drilled for the 34" radiator. see the holes that my efans are bolted into? those are the holes that the 28" radiator bolt into...if you have a 28" radiator, yours will be bolted into those holes and the holes where my radiator is bolted into will simply be left open in your header panel...


Hey, great explanation, solid way to confirm.
I do in fact have the 28" based on info here.
 

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HOT AIR BALLOON OWNER
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14,932 Posts
All 1500 trucks (Suburban/Tahoe have big ones with big options like Dual AC/Tow) had the 28 from what I've seen, until 2005.
 

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HOT AIR BALLOON OWNER
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14,932 Posts
yup, mine was from a suburban;) bought it for $16:) i love ebay


That's where I got my '05 fans and that OE harness :big_banana_Dance:
 

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SyTy Speed Shop
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229 Posts
This is a a very easy straight forward mod, remove the old shroud, clutch fan and rad and bolt in the new rad and efans and put all the hoses back on, took me about an hour to do mine and that was with flushing out the entire cooling system at the same time to get rid of the dexcool. I used a nelson harness for my setup, works great and easier to get than a factory harness.

I picked up the rad and efans, which are out of a 2007 with 20 or so miles on it for 300 bucks from a guy in Dallas. My rad also has the engine oil cooler built in that Im going to hook up here soon.
 

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Speed Holes
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5,190 Posts
Discussion Starter #12
This is a a very easy straight forward mod, remove the old shroud, clutch fan and rad and bolt in the new rad and efans and put all the hoses back on, took me about an hour to do mine and that was with flushing out the entire cooling system at the same time to get rid of the dexcool. I used a nelson harness for my setup, works great and easier to get than a factory harness.

I picked up the rad and efans, which are out of a 2007 with 20 or so miles on it for 300 bucks from a guy in Dallas. My rad also has the engine oil cooler built in that Im going to hook up here soon.

Nice work, sounds good. :shake:

I'm just curious, you mention you flushed out all the dexcool... well then what did you end up using in it's place?
 

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SyTy Speed Shop
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229 Posts
Nice work, sounds good. :shake:

I'm just curious, you mention you flushed out all the dexcool... well then what did you end up using in it's place?

I completely flushed out the system and used a 50/50 mix using the yellow prestone and water. I don't care for the dexcool, there has been lots of problems in the past.
 

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Speed Holes
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5,190 Posts
Discussion Starter #14
I completely flushed out the system and used a 50/50 mix using the yellow prestone and water. I don't care for the dexcool, there has been lots of problems in the past.
hm, interesting.
Well, unless I hear otherwise between now and then, I think I'll just keep it simple and stick with the dexcool... :hmm:
 

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HOT AIR BALLOON OWNER
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14,932 Posts
Just flush the Dex every two years and you'll be fine.
 

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Member
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3,161 Posts
Question: If I get the fans installed on my 04 what do I do as far as wiring them up? Do I need special connections? Harness etc? GM part #? Do I need to program them to work ie blackbear etcc?
 

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SyTy Speed Shop
Joined
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229 Posts
Question: If I get the fans installed on my 04 what do I do as far as wiring them up? Do I need special connections? Harness etc?
www.nelsonperformance.com about 100 bucks and you get a nice plug and play harness with all the relays needed, there is only a few wires to hook up and your done, one wire goes to the green a/c wire so that the passenger side fan runs on high anytime the a/c compressor clutch is engaged, and the other wires goes to pin 42 in the PCM connector, cant remember which color right now, but the instructions with the harness are very good. then you have to have the PCM tuned to control the fans. or you can buy a factory fan harness, but either way you still have to have the PCM retuned to turn them on.
 

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Member
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3,161 Posts
Does anyone have all the GM part numbers I need to do the e-fan swap? Ie: shroud, fans, fasteners etc... I hate to ask but I have no time to look this up and sure someone has the info handy. Need this installed before this weekend.
 

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HOT AIR BALLOON OWNER
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14,932 Posts
www.nelsonperformance.com about 100 bucks and you get a nice plug and play harness with all the relays needed, there is only a few wires to hook up and your done, one wire goes to the green a/c wire so that the passenger side fan runs on high anytime the a/c compressor clutch is engaged, and the other wires goes to pin 42 in the PCM connector, cant remember which color right now, but the instructions with the harness are very good. then you have to have the PCM tuned to control the fans. or you can buy a factory fan harness, but either way you still have to have the PCM retuned to turn them on.


Or you can use the OEM harness for about 1/3 of that, just like I did.
 

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Registered
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108 Posts
Hmm I dont quite get what you guys are talking about with the E fans? Is it just an upgrade to keep engine runing cooler? I have an 05 silverado that mean i Alreay have it? Sorry for the dumb question but I have been reading about e-fans on here an I dont understand.
 
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