Radiator swap

Crashnsnap

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I have a 1988 s1600 International with a 7.3 diesel. I currently have it torn apart and found out my radiator needs to be replaced. I want to replace the fan clutch with electric fans and a newer aluminum radiator. Has anyone tried this? I figure while I have it torn apart i might as well upgrade everything, I'm just not sure what radiator I can use. I won't be doing much towing with it and i live in Florida, so there aren't hills to worry about. Plus this will be more of a low rider then a heavy hauler. I've swapped out the rear axle with a 96 dodge 3500 rear end already.
 

Big Bart

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Crashnsnap,

Be patient, someone should reply, the challenge is most of us have a Ford F250/350 or E250/350 on this site. But some have other IDI based rigs. So may take a little longer for some feedback.

Let us know how it turns out!
 

franklin2

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I have no experience with that particular truck, so I don't know where you can get a radiator. I have been using the aluminum ones off ebay. 1st one lasted 10 years, so I am on my second one.

On the electric fans I caution you on that. I personally would not do it unless you are willing to spend some time and money. 1st off, those electric fans you can buy at the local parts stores for less that $100 each are not good enough. I ran 2 16 inch versions on my truck, and it would not keep it cool.

Also running those two fans, the alternator could barely keep up when I had the fans going, the lights going, and the A/C on high.

So if you are going to go with electric fans, you need to get the big expensive ones, or go to the junkyard and get some off a large vehicle that have enough airflow. But nothing is free, so that means they draw a lot of power. So you will need to upgrade your alternator to the 130 amp unit. And then you will find out the one single v-belt is not enough to turn the 130 amp alternator at full output, that is why most of them are serpentine belt drive. So you have to try and convert to dual v-belts or a serpentine system.

A lot of changes when the simple mechanical fan is large enough and works.
 

Crashnsnap

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@franklin2 thanks for the information. I was worried about the alternator not being able to keep up. I was hoping I could use a radiator from a Ford 350 but was wondering, would it cool it enough? The international and the Ford 7.3’s are the same, so I don’t see why it wouldn’t work. I would just have to make different mounts, adapters for the hoses and get a cheaper Ford aluminum radiator. They want $700 for an international one.
 

Rusgo

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I wonder if our radiators would even bolt up? If your radiator is is similar a custom setup is fairly easy on these.

Would guess your radiator is a good amount larger than ours.

I put electrics in mine. The serpentine setup has a higher output alternator. Upgrade is sorta easy. Leftover serpentine setups are getting harder to find

I used 3/16 aluminum plate for the fan shroud. Cutout holes for the fans. The fans almost fill the entire face

Have one fan wired into an interior toggle switch controlled relay. Other fan is controlled by a relay off the temperature sensor that controls the temp warning light. Used a sensor that turns the temp light on at 200 degrees. If the light comes on the fan turns on.

Fans never come on in the cold six months in the northwest

On the hottest days in traffic on hills, sometimes need both fans. Constantly have 3000 lbs in the back and 35" tires

Also have an auxiliary coolant pump going to the heater core. If truck ever gets too hot can pull over, turn pump and fans on, and engine cools off without it running

Check a few pics down for it


If you decide to go with electrics, get the biggest highest quality ones that would fit. If radiators are available, likely much easier to go that route
 

u2slow

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Smaller pulley will help put the alt "in the zone" . They don't charge much at idle otherwise.

The IDI rads are huge for a pickup. If I had to guess, the 'square' version (not the short/wide) is a better fit on the s1600. Dimensions can be found on rockauto, Spectra-Premium, etc websites.
 

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