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Modifying the Omix Radiator

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Steelyard Blues View Drop Down

Joined: 09 Oct. 2017
Location: Reno, NV
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    Posted: 21 July 2021 at 11:18pm

I have been battling overheating issues since I got my ’47 2A in 2017. The original radiator has been cleaned and repaired once and cleaned out again. I had a lot of rust in the block that required several flushes to get more of the rust out after the radiator was repaired. Even so, I still had problems after a “high speed” run. This usually entailed a few miles at 45-50+ MPH. Upon slowing down, temps would come up to 190-210+ and would have a hard time coming back down to 170-180 prolonged slow driving or sitting at idle. A hot shut down would often result in a boil over. On a recent hot Reno day, I ran her for several miles at 50+ MPH. Initially she was fine, but the temp pegged the gauge at around 250 when I came to a stop and would only come down a couple degrees after sitting at a high idle for several minutes. I thought I was going to kill the engine. Later, I figured that some more rust came loose in the block and plugged the radiator. After another flush of the block and radiator resulted in more rust coming out but there was no improvement in reducing temperatures.

Stan (Grampa’s Jeep) did a nice comparison of the Omix radiator to his original.

 Original vs Omix-ADA radiator - The CJ2A Page Forums - Page 1

After Stan’s professional review, I decided to give the Omix a try. The cost was not much more than having the old one cleaned out again. I’m lucky to have a Summit in town making returns easy if I didn’t like it.

The radiator I received did not come with a cap but I was able to use my NOS vintage one from the original radiator. The Omix radiator is aluminum with a steel shroud that bolts to the radiator.

Stan’s review covered all the issues that I observed:

1.       Straight inlet tube.

2.       Non-fixed mounting bolts.

3.       Short overflow pipe.

4.       No provision for side felt.

5.       Oblong shroud.

6.       No ability to use the shroud extension.


I thought I would attempt to correct some of these issues and, at the same time, make the radiator look more like the original.

First, the inlet tube would need to be cut off and a new piece, cut at an angle, in place. Not wanting to potentially void the warrantee and having limited TIG aluminum tube welding experience, I opted not to correct this. It does make the hose a little difficult to attach especially if you use the metal pipe section. (The lower fit fine.)

Second, the mounting bolts are loose. I epoxied them in place since it is impossible to get a wrench I there. When I went to mount it, the bolts would not align with the mounting holes. I had to break the bolts free with a plastic hammer. I think the remaining epoxy did help hold the bolts in place so that I could tighten them down.

Third, the overflow pipe is too short and a long section of rubber hose would not look original. I bought some ¼ soft copper tube, bent it into shape, extended it to well past the bottom of the radiator and painted it black. Since I could not weld/solder the copper to the aluminum, I used a short piece of hose with some shrink tube to hold it together.

Forth, I made side panels to allow for the use of the original felt. I cut two panels 13” x 3” and used my “Bubba approved” press break to make a 90 degree ½”tab. The panel is held in place with the bolts connecting the shroud to the radiator.





The correction of the oblong shroud opening and the inability to use a shroud extension took some work. Using a cardboard and the shroud extension, I made templates for new panels. I then TIG welded them around the perimeter of the shroud. I left the existing metal in place. The shroud extension required the relocation of a couple mounting tabs. I also TIG welded nuts and washers to the inside of the shroud to make assembly and disassembly of the extension easier.




Installation of the radiator was straight forward with just a little issue in connecting the upper hose.






A few things that I learned:

My shroud extension was a little beat up from a previous encounter with the fan. So, getting the opening correct was challenging. I ended up splitting the seam and rewelding it with a slightly larger diameter to get it to fit better. A new shroud would have made the installation better.

I did not remove the old radiator to use as a comparison as I was modifying the Omix. Unfortunately, I have the Jeep parked in the street and could not have it non-operational while I made the modifications. If you look at my comparison photos, the top round portion of the Omix shroud is mounted about 1” higher than the original. There is over and inch of fan clearance at the top but, at the bottom, there is about ¼”. If I have the radiator out again, I will redrill the six shroud mounting holes ½” lower. This should balance out the alignment.

Also, having the old radiator out might have helped me creating a template and getting the shape of the opening a little bit better.

I have only done one test drive so far. Outside air temperature was in the mid 80’s. For my short two mile “high speed” run to and from the gym, the temp remained at 160 and did not go past this on the next two miles when speeds were in the 30-40’s. When I parked after going a few blocks at 25 MPH, she was at 180 and with a fast idle, the temps started to immediately drop. So, hopefully, this radiator keeps the temps down in the hot August days ahead and no more rust breaks loose. 


1947 CJ2A, Body & Frame: 106327, Engine: J109205, Tub and Tailgate: 97077. Originally Luzon Red

1965 Johnson Furnace Company M416 #6-1577
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smfulle View Drop Down
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Joined: 16 Sep. 2010
Location: Ogden, Utah
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Points: 5613
Post Options Post Options   Thanks (0) Thanks(0)   Quote smfulle Quote  Post ReplyReply Direct Link To This Post Posted: 22 July 2021 at 12:26am
Nice job Micah. You went above and beyond with that thing.
48 CJ2A (Grampa's Jeep)
59 Chevy 1/2 ton
Grampa's Jeep Build Thread
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