Chevy & GMC Vans

Hi all. Im sure some of you are familure with my 383 vortec stroker swap I performed last year. now that it is summer and it is hot, I am running into a cooling issue. 90 degree day or hoter going down the freeway, coolant temp is right around 180-200. As soon as I stop during a trafic jam or whatever, the temp walks around 220ish.

Stock radiator(brand new btw)
stock pump, new also
stock 4.3 fan clutch and blade, clutch new.
factory shrowd that has been cut down to accomidate the added 4.5" of overall engine length.

I am wondering if the 4.3 fan blades have a differant pitch than the 5.7 because they cross referance differant part numbers. the fan cluch also has a differant part number.

Do you thing I have a radiator compasity issue or a under performing cooling fan issue? I find it hard to belive that a fan clutch doesn't draw as much air as an electric fan. Does anyone have specs on a stock fan and a fan off of a 5.7 thats out of an express. I am wondering if switching to an express clutch and fan will add cfm. thanks for looking.

-Vance

Living in my hot climate and towing upgrades in 80-125 f heat, I would never be comfortable with a 350 running a 4.3 rad, fan, shroud, clutch or twin cooling fans.

However, I understand that many of you V8 guys don`t tow toys through the desert, so you can perhaps get away with a 4.3 cooling system, but I wouldn`t recommend it for a 383 motor.

This is what I run for my extreme heat conditions, and my motor runs at 185-200f even when climbing the longest uphill grade (29 miles at 70mph, Chiriaco Summit on the 10 Fwy towards Blythe or Lake Havasu)

A `92 Chevy pickup rad, it`s a 1 core but the cores are 1 1/4 inches wide. ( Also found in early `90s Corvettes )

A modified to fit `92 pickup radiator shroud ( very important to have )

A 5 blade V8 pickup fanblade and fan clutch, but in the summer extreme heat I swap to a 9 blade HD from a `93 Caprice tbi 350 CopCar.

A high flow performance 185 f T-stat. Stock one for my `91 V8 is a 195 f.

New GM V8 waterpump ( cast iron ) fitted with a "Flow-cooler disc" to the vanes, which increases effeciency and flow.

My trans cooler lines do not flow into my radiator cooler, because I don`t need fast warm-up of tranny fluid for freezing temperatures, I never see them here. Just a huge motorhome sized 12 x 12 x 1inch thick air to air tranny cooler that is NOT mounted directly to my a/c condensor. ( because that will transfer heat across )

Some simple sheet aluminium ducting that scoops and directs oncoming air directly into my a/c condensor and radiator, from the sides and below. For all you guys with new-style front ends, cut out those "ducting holes" from below the main bumper line and guide all that incoming air up into your a/c and rad. Ducting will help your a/c run cooler also, on ANY Vehicle, highly recommeded if you can fabricate with aluminum or rubber tiles.

And just to let you know, My van ran this cool as a "short-nose" `86 cargo with these mods, in `98 when I completed my V8 swap. Then I moved up to transplanting a beautiful " long-nose" which is now called "new-style" haha!

And a new-style front end, gives you an extra 8 inches of extra room to mount your rad and fan.

This was the actual "flow-Kooler" disc that I fitted onto my 2.3 Ford Turbo sandrail, so I made another for my V8 Astro, to improve coolant flow.







Got a pic of my 9 blade Cop-Car Caprice 350 TBI fanblade here somewhere.... but I can`t find it right now.... A V8 5 blade will work for you non 120f guys.

Very good info, Darren. Thanks for posting. All of the tried and proven methods for swapping in a V8 that I've learned on this site will make my swap so much easier.

Good stuff Darren.

Thanks a lot man. I still have the clutch fan and clutch from the 3500 express van that I took the engine out. If I put that on, do you think that I will notice a differance? Or do you think that I have a lack of cooling compacity issue? Lots of good info.

Fit the V8 radiator, that is your main problem.

And it does fit between the chassis rails.

do you have any photos? I am curious of how you are mounting it. I am assuming ther are no ways to utalize the factory mounts.

-Vance

http://cgi.ebay.com/ebaymotors/ws/eBayI ... MEWNX%3AIT

This is the radiator that I bought. It's almost exactly the same dimensions as the stock radiator, only its about an inch or so taller and it's two-core. Obviously, I'll have to make mounts for it. I would think that this is big enough for my application.

Any thoughts?

-Vance

With Aluminum welded endtanks? "not plastic pressed together with the core" if so that is good for that price. Make sure that you fit either a 4.3 or 5.7 fanshroud that fits the whole rad surface (you may have to fabricate simple brackets, > I did)

You may have to build simple rubber mounts to support it, and keep it from vibration. ( look at other cars / vans / trucks in the junkyard for guidence)

As I said before, use a mechanical 5.7 fanblade (5-blade) with a new or good fan clutch, but If you see extreme heat in towing conditions like I do, a 9 blade is also available.

I think I am going to weld on aluminum wings on both sides of the radiator to utilalize the factory mounts. I may or not have the sufficent aluminum TIG welding skills at this point with my lincoln at home, I shal practice quite a bit first so I dont waist a new rad. [-X . Will for sure post pics if I do tho.

-Vance

No, just make new brackets for the top and bottom with rubber mounts on them, don`t be tig welding on that new rad.

This is so weird, Cause I live in central ohio with Vance and I have absolutly no cooling issues. Even while towing. I'm running the stock v6 rad, v6 clutch fan, and the stock thermostat (195) and stock waterpump. No AC condensor. I've got a regular Discount parts tranny cooler in line with the radiator tranny cooler, running 50/50 antifreeze in the radiator. The only thing I haven't got is a shroud. Everytime I think I get one right the stupid clutch fan starts hitting it. I don't use the oil cooler in my radiator either. I've put almost 15,000 miles on this setup with no issues. Could a 350 and a 383 be that big of a difference when it comes to cooling?

BTW Vance I really wanna see your van sometime. :-)

Logan: Do you run headers by any chance? I run shorty headers and they seem to put out a lot of heat, they are even wraped. My van is lowered, I mightnot get as much wind threw comparied to a stock ride hight van(asuming your's is stock ride hight.) My SB should have more power than a stock 350, this might also be a contributing cause too.

Socal, your probably right, I will look and see if I can weld/bolt on brackets to the bottom of the coresupport to mount the bottom of the radiator. I know that a lot of people talk about runing a taurus electric fan, does anyone have a cfm rating for this fan and the stock 350 clutch fan set up? I am really thinking of converting to an electric fan. I just wanna know that it is gonna be overkill, hehe.'

-Vance

I have a question....Socalli said to use a rad from a 92 truck. What size rad is it? A wider rad then stock will interfere with the ac lines. I am curious to see how it fits in..

phatmaxx87 wrote:Logan: Do you run headers by any chance? I run shorty headers and they seem to put out a lot of heat, they are even wraped. My van is lowered, I mightnot get as much wind threw comparied to a stock ride hight van(asuming your's is stock ride hight.) My SB should have more power than a stock 350, this might also be a contributing cause too.

Ahh, I see. Nope I'm running stock manifolds and still at stock ride height. Wow, I never thought those would be contributing factors. Cool. thanks