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Today I replaced an aging and cracked radiator in my 2007 LX470. At the same time I removed the OEM clutch driven mechanical cooling fan and installed a pair of high flow electric fans and a nice Derale aluminum shroud. Electric fans will free up some HP and MPG but not very much. Maybe 5-10 HP on a good day and 1-2 MPG. Probably not worth it unless you like to do stuff like this.
Removed the stock rad, duct and fan. I reinstalled the 4 nuts on the water pump pulley along with washers to take up the play. You can see the dried coolant all over everything from the cracked rad.
I bought this nice Derale twin fan shroud that has rubber flaps to allow air to bypass the fans for more flow at higher speeds. At low speeds or when stopped the flaps seal against the shroud so the fans can pull more air through the radiator. This shroud is designed for V8 muscle cars and flows a TON of air. Definitely more than the OEM fan can move at idle.
The new radiator is a CSF replacement radiator. The core is actually slightly taller than the OEM core by a couple of inches.
Derale twin fan shroud: Amazon.com: Derale Performance 16837 Gray/Black High Output Dual Radiator Fan: Automotive
CSF all-aluminum replacement radiator: https://amzn.to/39lzg5n
Aluminum tape: https://amzn.to/32NGLj7
I mounted the shroud to the rad using the included 90 degree aluminum plates and then sealed the entire shroud to the radiator with aluminized tape. The shroud fits almost spot-on side to side, but top to bottom it's about 2 inches too short. I drilled out the rivets in the corners so I could carefully bend the top and bottom ends of the shroud out at an angle slightly. This allowed them to taper out to the edges of the rad and took up the extra space and now the fans can draw through the entire core.
Installed the radiator. Surprisingly it actually goes in easier than the OEM setup because you don't have to hold the shroud and the fan together and wrestle with them. Even though its thicker, it just slots in.
For now the overflow tank is just zip tied there but I've got a few ideas of where else to put it.
At the same time I installed an AC aux fan. I followed @whitenoise great write-up thread so you can just go there if you want to know how I did it. The fan is relayed and switched by the AC pressure switch so it works just like factory and independent from the main cooling fans.
So that's all great but without a way to turn on the fans then your engine quickly overheats. To control the fans I chose a Honda water temp switch. This switch closes at approximately 195F. Each fan has it's own relay that is activated by this thermo-switch. It's possible to have two thermo-switches at two slightly different temperatures, so one comes on first and the second only if it needs to. Or the fans can run off a variable speed circuit so they come on at low speed first, and then ramp up as needed. These options would reduce noise until full cooling capacity is needed. I am going to experiment a variable speed controller, no sense in running them full blast if we don't need to. That's why we chose electric fans in the first place!
Temp sensor: Amazon.com: OKAY MOTOR Engine Coolant Temperature Sensor with Pigtail Connector for GM GMC Chevy Cadillac Buick Oldsmobile Acura Isuzu Honda: Automotive
The thermo-switch was installed in a simple piece of steel pipe that was the right size to slip inline in the upper rad hose. I have seen people drill into the rad end tanks to mount the switch but since the end tanks are plastic I decided not to do that and to do it this way.
So far everything is working as advertised. The engine heats up, the fans come on, it cools down, they go off and the cycle repeats. The engine is now quieter, especially on cold starts. No more starting the truck and hearing the massive fan coming on and blowing everyone away. The electric fans are definitely quieter than the OEM fan when running full blast. AC works great too
Today I replaced an aging and cracked radiator in my 2007 LX470. At the same time I removed the OEM clutch driven mechanical cooling fan and installed a pair of high flow electric fans and a nice Derale aluminum shroud. Electric fans will free up some HP and MPG but not very much. Maybe 5-10 HP on a good day and 1-2 MPG. Probably not worth it unless you like to do stuff like this.
Removed the stock rad, duct and fan. I reinstalled the 4 nuts on the water pump pulley along with washers to take up the play. You can see the dried coolant all over everything from the cracked rad.
I bought this nice Derale twin fan shroud that has rubber flaps to allow air to bypass the fans for more flow at higher speeds. At low speeds or when stopped the flaps seal against the shroud so the fans can pull more air through the radiator. This shroud is designed for V8 muscle cars and flows a TON of air. Definitely more than the OEM fan can move at idle.
The new radiator is a CSF replacement radiator. The core is actually slightly taller than the OEM core by a couple of inches.
Derale twin fan shroud: Amazon.com: Derale Performance 16837 Gray/Black High Output Dual Radiator Fan: Automotive
CSF all-aluminum replacement radiator: https://amzn.to/39lzg5n
Aluminum tape: https://amzn.to/32NGLj7
I mounted the shroud to the rad using the included 90 degree aluminum plates and then sealed the entire shroud to the radiator with aluminized tape. The shroud fits almost spot-on side to side, but top to bottom it's about 2 inches too short. I drilled out the rivets in the corners so I could carefully bend the top and bottom ends of the shroud out at an angle slightly. This allowed them to taper out to the edges of the rad and took up the extra space and now the fans can draw through the entire core.
Installed the radiator. Surprisingly it actually goes in easier than the OEM setup because you don't have to hold the shroud and the fan together and wrestle with them. Even though its thicker, it just slots in.
For now the overflow tank is just zip tied there but I've got a few ideas of where else to put it.
At the same time I installed an AC aux fan. I followed @whitenoise great write-up thread so you can just go there if you want to know how I did it. The fan is relayed and switched by the AC pressure switch so it works just like factory and independent from the main cooling fans.
So that's all great but without a way to turn on the fans then your engine quickly overheats. To control the fans I chose a Honda water temp switch. This switch closes at approximately 195F. Each fan has it's own relay that is activated by this thermo-switch. It's possible to have two thermo-switches at two slightly different temperatures, so one comes on first and the second only if it needs to. Or the fans can run off a variable speed circuit so they come on at low speed first, and then ramp up as needed. These options would reduce noise until full cooling capacity is needed. I am going to experiment a variable speed controller, no sense in running them full blast if we don't need to. That's why we chose electric fans in the first place!
Temp sensor: Amazon.com: OKAY MOTOR Engine Coolant Temperature Sensor with Pigtail Connector for GM GMC Chevy Cadillac Buick Oldsmobile Acura Isuzu Honda: Automotive
The thermo-switch was installed in a simple piece of steel pipe that was the right size to slip inline in the upper rad hose. I have seen people drill into the rad end tanks to mount the switch but since the end tanks are plastic I decided not to do that and to do it this way.
So far everything is working as advertised. The engine heats up, the fans come on, it cools down, they go off and the cycle repeats. The engine is now quieter, especially on cold starts. No more starting the truck and hearing the massive fan coming on and blowing everyone away. The electric fans are definitely quieter than the OEM fan when running full blast. AC works great too
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