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Radiator Recommendations for a Swapped-In V8

5K views 7 replies 3 participants last post by  DECJ 
#1 ·
I have a 2000 Jeep Wrangler TJ that has a swapped-in Dodge Magnum 5.9L V8 engine. As part of the V8 swap, an Advance Adapters #716687, 3-core copper/brass radiator for Jeep Wrangler TJ's with V8 conversions was installed along with a fan and fan clutch assembly from a ZJ.

In driving my TJ both on-highway and off-road, I notice that it is typically running too hot, even when the outside temps are not all that hot and I am not doing anything too tough or demanding. Where I used to see my original factory 4.0L I6 engine run consistently about 210 on the temperature gauge in such instances, the 5.9L V8 is running more in the 220-230 area and sometimes even goes up from there, especially if the A/C is on or I am doing some slow off-road crawling.

Since my thermostat, water pump, and serpentine belt are all in good operating condition (and there is only about 2000 miles of use on the Advance Adapters radiator), this all leads me to the conclusion that the #716687 radiator just doesn't have enough cooling capacity for my Dodge Magnum 5.9L V8 engine.

BTW, I have checked with Ron Davis Racing Products in Arizona, and they can custom build an aluminum down-flow radiator for a V8 equipped TJ, however, they want $550-$600, and that is beyond my budget.

Anyway, I would appreciate it if anyone who has a V8 in their TJ (or otherwise has experience with V8 swaps) could recommend a better radiator with more cooling capability for my application.
 
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#2 ·
I would think that the rad is enough to cool the engine.There may be a couple of alternatives to your dilemma.
1) instead of a new radiator, how about an electric fan, with a lower cut in temperature.
2) Sometimes the heated air is trapped in the engine compartment and cannot escape, this also causes the engine to overheat. Take of the hood and go for a drive to see if you still have this problem.
 
#3 ·
I would think that the rad is enough to cool the engine.There may be a couple of alternatives to your dilemma.
1) instead of a new radiator, how about an electric fan, with a lower cut in temperature.
That is something I am also thinking about.
2) Sometimes the heated air is trapped in the engine compartment and cannot escape, this also causes the engine to overheat. Take of the hood and go for a drive to see if you still have this problem.
I have an AEV Heat Reduction Hood on my TJ, so I don't think that's the problem, but thanks for the idea.
 
#4 ·
I see you have a hi-stall torque converter, are you running an independent cooler for your transmission? With air conditioning and a winch blocking airflow to the main rad you may have to relocate a trans filter
 
#6 ·
Yes, I have a separate cooler for the transmission fluid and it is remotely mounted from the main radiator.
 
#5 ·
Does the 5.9l's water pump spin the same direction as your 4.0l's? If not, then the fan is turning the wrong direction and won't move much air. Another thing to consider is the 5.9l sender's resistance may be different than the 4.0l's, which would make the gauge inaccurate.
 
#7 ·
Yes it does. In terms of the wiring, Evan Austin did the work and he is pretty well known for the soundness of his conversion wiring harnesses for this swap, so I would hope that the temp sensing and instrument interface is pretty much dead on (but it's a good point to raise)
 
#8 ·
After weighing a number of factors (time being the biggest one), I have decided to go with an Advance Adapters #716691-AA aluminum 2-core cross-flow radiator. It's built by Custom Aluminum Radiators in Kingman Arizona for Advance Adapters and I can get it in about a week. I probably would have gone with a Ron Davis custom aluminum down-flow radiator, however, they had at least a 30-day lead time to even get to the point of shipping. Here's a pic of the new Advance Adapters radiator:


The core dimensions for the aluminum cross-flow radiator from Advance Adapters are 17-7/8 wide x 18-1/4" high, so that will provide 326 square inches of surface area. As a comparison, the core dimensions for the existing Advance Adapters copper/brass down-flow radiator in my TJ are 17-7/8" wide x 19-3/4 high, so that provided 353 square inches of surface area, however, it was a less efficient 3-core design that was 2-1/4" deep, while the aluminum cross-flow is the better cooling 2-core design at 3" in depth. Some adapting and new brackets will need to be fabbed-up to use my existing down-flow shroud on the new cross-flow radiator, however, that is doable.

The remaining question is going to be airflow. Steve Roberts at Advance Adapters continues to feel that their 16" Spal electric fans will not move enough air for my application (they top out around 2300 cfm). Evan Austin of Backwoods Offroad suggests a 15" Flex-A-Lite Black Magic Extreme 180 fan which moves around 3300 cfm of air. However, the 18" Lincoln Mark VIII fan that Deri0953 uses with his Ron Davis cross-flow radiator wins the cfm contest hands down at 4500-5000 cfm. Anyway, based on Steve Roberts recommendation, I plan to initially start out with the new Advance Adapters aluminum cross-flow radiator and use it with my existing 5.9 Limited Grand Cherokee mechanical fan and fan clutch assembly and see what cooling improvements can be gained with that set-up. If that doesn't end up cutting the mustard, then I will probably need to look at the Black Magic Extreme 180 fan or the Lincoln Mark VIII fan.
 
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