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XJ radiators, a review.

Cold Case arrived. A few comments:

- Looks to be very nicely made. Very impressed with the apparent quality.
- No shavings in the end tanks.
- I'm really surprised that the o-ring on the Renix temperature sensor bung doesn't seal.
 
Well, Cold Case wins another QC fail. The inverted flare fitting for the upper transmission fluid heat exchanger line bottoms out on the radiator body bung before the flare faces make contact.

I think the fitting is fine, and instead the bung on the radiator is too deep. I suppose I can grind down the bung.

Or I could try to seal the fitting with a fiber composite flat washer.
f6635196a09087c4b3ed894d2fc5bb58.jpg


Sent from my SM-N950U using Tapatalk
 
Bummer.

Having a stick shift I didn't find that detail.

The challenge with grinding down the bung is keeping out all abrasives/metal particles. I would look for a rubber stopper that fits the internal opening, then clean everything out with brake cleaner after grinding but before removing the stopper. Then I would probably clean everything with brake cleaner again.

The fiber washer doesn't appeal to me.

I would also contact Cold Case and complain about it. I would ask them to fit check some of their own stock on hand and find one that seats properly. Probably an impossible task on their end, but I would still ask them to do it.
 
After some measurements, I determined that the base of the brass fitting and the surface of the bung both needed to be ground to ensure that the flare faces make contact. I ended up stuffing foam in the bung before grinding, and then I vacuumed out the entire area before and after removing the foam. All went well and now the upper fitting is installed. The lower trans cooler fitting appears to seat properly (with just perhaps 1/2 turn before the fitting bottoms out).

I used a hard composite water fixture washer for the Renix bung. Put some RTV gasket maker on both sides. Hoping to have time to install the radiator this weekend.
 
The Cold Case is installed, and my initial impressions are that it clearly cools better than the Summit/TSM. I've only had a short amount of drive time thus far, but it is holding coolant temp steady on long steep street where water temp with the Summit/TSM would increase by 10 deg F. And the Cold Case creeps up less during extended idle.

Install was pretty painless, but some tweaks were needed. Here's a complete summary of the mods:

- Per Anak's experience, I ditched the o-ring on the Renix temp sensor plug. I found a fiber composite water faucet sealing washer at Ace that was the perfect size. I sealed it with a thin layer of RTV on both sides, but I suspect RTV is not necessary. In the first hour of driving around, its working fine so far.
- To allow the upper transcooler brass adapter to seat properly, I had to make clearance by grinding down the transcooler bung on the radiator and by grinding down the bottom of the brass fitting.
- Per Anak's recommendation, I removed the overflow nipple on the radiator fill neck and reinstalled it with thread sealer. Mine was reefed in there good, but it had no thread sealer, so I didn't want to take a chance on it leaking. I had to use some lubricating oil to keep the threads from galling during removal.
- Per Anak's recommendation, I rinsed out the radiator. Some fine shavings came out. I think they are all too small to clog a coolant passage, but better to not have that stuff circulating.
- The overflow nipple is sized for 3/8" hose, but the stock hose is 5/16", so I had to cut a small piece of 3/8" and merge it to the factory overflow hose with an adapter.
- The overflow nipple sticks out further than stock, and gets in the way of installing the electric fan. I removed the nipple to allow installing the fan, but cutting 1/4" off the end of the nipple would resolve this without causing any issues. With the barb removed from the end of the nipple, it might even be possible to shoehorn on 5/16" hose.
- My Cold Case radiator came with a nice brass petcock, but I ditched it in favor of an easier-to-reach drain setup like what I did with the Summit.
- The clearance to the mechanical fan hub is fairly tight, even with a factory fan hub. Its about 1/2" of space. I had to install the fan shroud as I was installing the radiator. Before dropping the radiator into the locating holes, I pushed it towards the front of the vehicle and tilted the top away from the engine. Then with a bit of finagling, I got the shroud past the fingers on the fan hub. The radiator really should be set up to sit forward by 1/4".

Other than these minor issues, it was smooth sailing. One reviewer on the Cold Case website said that the quick release fitting on the lower transcooler hose wouldn't fit onto the adapter, but my went on perfectly.
 
After several days of around-town driving, I can confidently say that the Cold Case radiator is extremely effective. At idle and under decent load (e.g., hills with the TC not locked), the coolant temp sits at the t-stat set point or just a few degrees F above. And on downhills, it drops below the t-stat set point. During a short downhill on the freeway today with ambient temperature around 80F, the coolant temp dropped 7 deg F below the set point. Neither the 1-row CSF that came with the XJ or the Summit Copper/Brass were anything like this. I'm definitely happy that I tried this radiator.
 
I have carefully followed this thread and have been searching through various XJ forums on the issue of achieving the maximum cooling potential (at manageable cost) in a replacement XJ radiator. Minor issues of fitment can be addressed with my limited metal working skills and the all metal versions show significant reliability in my internet searches. I am convinced the the higher density of tube spacing gives the aluminum radiator a cooling capacity advantage. But the most convincing issue (to me) for heat rejection in a given volume is the effective volume of tube moving coolant and the surface area of that tube. For that reason, for the same core thickness, a single row design would seem to be superior to a 2-row and a 2-row would be superior to a 3-row. I was about to pull the trigger on a purchase of a Champion 2-row with a core thickness of 1.75 inches when I stumbled on a single core all-aluminum radiator by VRracing on Amazon that is 2.5 inches thick! Further, a photo of the core is offered in product description clearly showing the single row structure but also showing the presence of turbulator-like inserts usually designed to increase the level of heat transfer from the interior tube wall to the liquid coolant. I've tried to enter the link below for the core image. Its the last image in the product description.

From what I can see and have verified with the supplier, the overall dimensions are well within the fitment limit for our XJ's (mine isa '96), the price is almost suspicious and as near as I can discern, this could be an excellent solution for overheating XJs operating in severe conditions of heavy load and 100+ F ambient temperatures. Looking forward to hearing about what all I've missed.

https://www.amazon.com/GPLUS-Aluminum-Radiator-CHEROKEE-COMANCHE/dp/B07CSQZ78X
 
In my have-no-idea-what-I'm-talking-about opinion, it looks like they used the core of a gas-to-gas heat exchanger, HVAC Condensor, etc. The "fin spacing" on those turbulators looks entire too small for regular 'ol coolant in a ~30 yr old iron block engine. Looks like a clog waiting to happen. Definitely suggest a coolant filter if you decide to get one

For reference, here's the spacing on intercoolers: https://www.miataturbo.net/diy-turb...tercooler-have-turbulators-turdulators-86129/

Turbulators for air charge and oil coolers: https://www.chaluminium.com/products/detail/aluminium-welded-tubes-with-inserted-turbulators.html

Internal turbulators on other radiators: https://www.motortrend.com/how-to/ctrp-0910-critical-engine-cooling-technology

Here's Flex-A-Lite's universal LS radiator that uses extruded tubes w/ internal turbulators and only a single, wide core. They indicate that it performs better due to increased contact between the coolant and the tubes (due to the turbulators). Looks to be only 1/3 as many passages in this Flex-a-Lite than in that one off Amazon, reducing the risk of clogging. https://www.flex-a-lite.com/radiato...ore-universal-radiator-34-x-20-ls-engine.html

Mishimoto's radiator for JKs: https://www.quadratec.com/sites/def...erformance-radiator-jeep-wrangler-jk-core.jpg Note that there are only 3, maybe 4 passages in theirs.
 
Jim, thanks for posting those very interesting links. After my initial enthusiasm, I looked more closely at their core photo. I agree, its clearly an image of a core used for air-to-air or possibly high pressure oil flow in and oil cooler. Further, the tube spacing and thicknesses are not consistent with their photos of the radiator. The radiator pictures show 28 tubes over 10.82 inches, consistent with 3/8" tube spacing. This would suggest tube thickness of around 0.65 mm, so its possible that the actual tube spacing is even less. I only know of 3/8 or 5/16" spacing in aluminum cores. If this is a high efficiency core with 5/16" center to center spacing, this would suggest 2.0 mm which tubes.

So at this point we are left with a single row radiator with a rather thick core. The stated thickness is 2.5", but their dimension photo shows that this is the thickness of the end tank. Core could be 2 inches which still suggests a very wide tube in the structure. I'm going to try for more information from the seller!

But I completely agree, if the core is as per the image, it would be a real clogger!
 
FrankGRUN said:
Jim, thanks for posting those very interesting links. After my initial enthusiasm, I looked more closely at their core photo. I agree, its clearly an image of a core used for air-to-air or possibly high pressure oil flow in and oil cooler. Further, the tube spacing and thicknesses are not consistent with their photos of the radiator. The radiator pictures show 28 tubes over 10.82 inches, consistent with 3/8" tube spacing. This would suggest tube thickness of around 0.65 mm, so its possible that the actual tube spacing is even less. I only know of 3/8 or 5/16" spacing in aluminum cores. If this is a high efficiency core with 5/16" center to center spacing, this would suggest 2.0 mm which tubes.

So at this point we are left with a single row radiator with a rather thick core. The stated thickness is 2.5", but their dimension photo shows that this is the thickness of the end tank. Core could be 2 inches which still suggests a very wide tube in the structure. I'm going to try for more information from the seller!

But I completely agree, if the core is as per the image, it would be a real clogger!
Click to expand...

Multiple reviewers said the radiator leaked within a relatively short number of miles. Even if its a very effective radiator, I wouldn't buy it for that reason alone. Also, if its really 2.5" thick, the mechanical fan hub is going to be really close, probably a little more than 1/4" away.
 
Agreed, early leaks and too many with very recent reviews. I had hoped to find a large tube radiator with 1" or even 1.25" tubes (Griffin is beyond consideration). The 1" tubes of the 2 row American Eagle by Champion would have been nice, but its no longer offered by Champion.
 
You might also take a look at the Ron Davis radiator.
Jeep-Cherokee%20radiator-91-2001-1-26CH9101.jpg
 
The Ron Davis looks impressive but out of my price range, unfortunately. I contacted Champion and was told they don't have any intention of offering the thicker core American Eagle radiators with 1" tubes. They suggested that the issue was leaks developing with large (thick) cores. Their explanation was stress due to frame flex in off road driving and possibly problems intrinsic to the way the unibody is designed. For the same reason, they are no longer offering their 3-row XJ radiator. In any case, my current best option is to go with the Champion EC1193. I have corresponded with several Champion XJ radiator users who have verified that the company stands behind their lifetime warranty, so that's a serious plus. One of my engineering friends suggested that the use of plastic end tanks could be a stress relieving function for long narrow core if proper sealing engineering is used.
 
There is a little truth in that but my Griffin is going strong now after 6yrs but I don't have any body flex.
 
Major new development! I was pressing a Champion technical rep about the reported (2019 and before) coolant leaks at the core to end tank junction in their all aluminum 1193 product. Most leakage reports I found were for the 3-row version, although some were for the American Eagle thicker core version or for the 2-row. Generally the leaks appeared after 6 months of usage. The tech replied that this due to radiator mount twist and flex that overstressed materials and the tank welds. He insisted that they were having no significant problems with their 2-row version - they no longer sell the AE or the 3-row. So far the conversation mirrors the one I reported above, but with more detail.

Then the new development! He then said that their engineers designed a new 1193 radiator that was engineered to resist any twist/flex issues and provide a major enhancement for all high stress cooling problems including off road. This is their BC1193 plate and fin radiator built in the same form factor as their 2-row EC1193 BUT it is a 1-core with a total core thickness of 2.125 inches with tank thickness of 2.375 inches. This would appear to be an excellent solution to my problems of cooling and reliability with their lifetime warranty. There are only two problems with this solution ... 1) Its a very new product with just a few short term reviews and 2) its pricy at $375 list. Now, I am going to pull the trigger unless there are serious negative experiences shared!
 
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