XJ radiators, a review.

[sberrett]

Ok here's my latest report
I've read this whole review thread a few times over as well as everything else on the internet regarding XJ cooling issues. Even started some question threads over the years. Here is a quick recap of my issue an my solution.

94 XJ with 3.5 RE lift, 31 inch tires has always ran way to warm-hot since I owned it (got it back in 2005). Over the years I've ran a GDI 3 core and various other 3core all metal radiators before using CSF radiators over the last few years. When my last CSF 3 core started leaking (2671) I decided to try the regular 2 core (2760) version. I bought that in November of 2022 and it once again performed ok on the highway, but rand noticeably warmer than the previous radiators I had. Stop and go city traffic had me always around 215 and would usually creep up to trigger the e-fan. Inclines/mountain grades had me 236-245ish. Desert driving even on flat highways had me at 225-230.

I had also replaced the following items on my cooling system

• New ZJ fan clutch (Napa 272310)
• Hayden 678 universal aux trans cooler
• New fan shroud
• New waterpump
• New motorad (SNN-2000-195) 195 thermostat
• New hoses
• HCV delete
• Flushed the system multiple times (coolant was always green, never rust present)
• Block test for combustion gas in coolan
• Compression and Leak down tests (all within spec)
• New coolant sensors (thermostat and engine block)
• Added a digital temp gauge for better accuracy
• Cleaned the condenser with coil cleaner from home depot
  Re-aligned all the condenser fins with alignment rake/tool

This last CSF 2760 only lasted 3 years before it started leaking again and I was once again scouring the internet for a solution. I was going to give the Champion BC1193 a try, but I kept seeing people mention keep the cooling system as close to OEM as possible. That was the one thing I had never tried. I was, and still am skeptical of plastic tank aluminum core radiators and, but decided it couldnt hurt to try. I decided to go with the OSC 1193 on Summit. I just installed it last Friday and it was a direct drop in and fit with zero issues. I had the old one out and new one installed in about an hour.

After filling it and burping I could already tell the difference. T-stat opens and it now idles at 200-205. Same temps for stop and go traffic in the city. On the highway I'm at 198-200. About 200-205 on grades/inclines that would previously get me instantly up to 224 and kick the e-fan on and require the heater in more continual climbs.. I now have the added bonus of being able to use my AC in hot areas too (was 106 where I was this weekend)

I hate to admit it, but a 120 dollar oem style plastic tank aluminum core radiator solved the issues I had been throwing money at and chasing after all these years.

 

[Unclewolverine]

I hate to admit it, but a 120 dollar oem style plastic tank aluminum core radiator solved the issues I had been throwing money at and chasing after all these years.

Hopefully more people will listen now. Cheap plastic tanked for some insane reason works best!

 

[sberrett]

To be honest, I was completely dismissive of that suggestion when it popped up every time. Like "psssh what do they know? this thing is 2/3 core and all metal and costs 400 bucks, it has to be good!"


I have no idea how this thing is more efficient than those, but it just seems like the brass/copper ones they retain way more heat than they can dissipate. I'm still curious how the Champion radiator would do, but at this point im just happy its over with.

 

[kastein]

Already done that on all 3 trail rigs. Sons stock rig still has trans lines running through radiator.

I've done just about everything you can imagine to get to the bottom of the overheating problem with no clear solution. I have a couple of theories, though. One is that a clogged heater core can cause flow issues. I've even bypassed the heater core on 2 of the XJ's.

Another is that one or more of the coolant passages in either the block or head become constricted with corrosion and restrict the flow of coolant. Yet another, and the most plausible is that the squatty design of the XJ radiator, due to the short nose of the grille, prevents the coolant from flowing over a larger area than most other taller radiators. I think the whole system is marginal at best, and is always on the edge of overheating. When one or more of the components stops functioning even a little bit, it throws the whole system into disarray.

I have run both with a bypassed heater core on one Jeep and with each heater line capped off on another for a year. Neither overheated, so it's not that.

I suspect it is sediment and corrosion buildup in the block and head as you noted.