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1990 K5 Radiator Updagrade

Justin Fleming

Justin Fleming

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Location
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At this time my truck has a small 1 core radiator, I want to upgrade this to the biggest radiator that will fit in it. Does anyone know what vehicle specification I should put in a parts finder to get the right one. Something like 1986 diesel 4x4 suburban or 454 suburban, or what I should be looking for off of LMC. I am sure I will then need to get the correct mounting bracket and modify the shroud some.
 
Factory or aftermarket type? Are you willing to mid or should it bolt in?

I have a radiator from a 6.2 CUCV in my 91, this is the biggest factory bolt in. The radiator hose necks are the wrong size for gas engine hoses so you have to have them changed or figure out a hose conversion, that's the easy part. The tough part is the mounting brackets are very hard to come by used and I don't think anyone makes them aftermarket.

There were couple of threads recently on this, one is in the Wanted forum.
 
What year was the cucv? When looking on LMC it looks the the 6.2 diesel is a 2 row not a 4 row
 
Mine is a 4 row BUT aftermarket has their own rules.

I believe CUCV's are 83-84.
 
Anyone have any new updates or thoughts on this, I am looking to tear it apart this weekend...
 
I have a 454 four core in mine. You have to have the brackets and shroud, which as mentioned above are VERY hard to come by. You will have to relocate your charcoal canister for it to fit. factory threaded holes are there in the core support. It is 19" high and 33" wide.
 
You can look at my build thread. Made the switch from a single core small block radiator to the 6.2 diesel setup. Much more cooling. But as others have said, you need the specific fan shroud, upper plate and hold down brackets. There is a right and left bracket by the way too. I ended up with 2 rights in my search. The parts are out there. Guys here have them. I posted up a wanted ad and I got a few different responses with guys that had the parts.
Size comparison

Size comparison


In my case the stock 5.3 hoses matched up to the 6.2 radiator. Upper hose was a little tight but I gave it a little lube and it slipped on without much fuss.
 
The hold down brackets go on each tank to the core support, what does that top plate do in the photo below the shroud?
 
I'm in the process of something along the same lines.
Diesel radiator shroud but went with a spectra radiator for a 1998 big block equipped truck.
Shares almost Identical dimensions to the 6.2 radiator
 
You have to look closely at the core support. Drivers side you'll see where the holes are for the larger radiator upper plate. It's angled there, you can't just move the "base" radiator mount out. There is no modifying the shroud, you need the BBC/Diesel one to increase the swept area of the radiator.

We ask these trucks to do more than they were designed for, there is room for outside the box thinking. Bigger doesn't have to be the only solution to cooling issues.
 
Spectra CU774 for the radiator. I can't seem to find the part number for the saddles. I do know this, I'll had to do was tell my local napa I needed them for a 6.2L diesel squarebody and they got me the ones that fit.
 
ZooMad75 said:
Spectra CU774 for the radiator. I can't seem to find the part number for the saddles. I do know this, I'll had to do was tell my local napa I needed them for a 6.2L diesel squarebody and they got me the ones that fit.
Click to expand...
If I go with this CU774, do I need different upper and lower hoses? Do you know what the correct combination of hoses is?
 
Justin Fleming said:
If I go with this CU774, do I need different upper and lower hoses? Do you know what the correct combination of hoses is?
Click to expand...
I don't think I caught what engine you had. On mine with the 5.3 I used stock hoses for a 2001 Silverado and they matched up just fine.
 
Not having put that combo together personally I can't say 100% the hoses line up. The lower hose probably without a problem. But the upper hose has the inlet further to the driver's side fender. So the hose needs to have a little more length. The other issue would be is that the hose nipples on the radiator are larger than the smaller radiators, so the hoses might need a little help going on.
 
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