'89 swaping radiator w/out cap to one with

I have an '89 Cherokee with the old style cooling system that does not have a radiator cap. Well this is a pain when flushing the coolant so I am converting to a system with a radiator cap.

the oem radiator has what looks like a temp. sensor that controls the electric fan. The new radiator that I bought does not have place for this sensor to be attached. Does anyone know how to rewire this sensor to the engine temp. sensor or any where else.

thanks
Dan

The a newer style HO tstat housing has a bung for a temp sensor. It will fit on the renix head. But I'm not sure if the original temp sensor fits in the bung. It's been so long since I did this, I forget. My rig has a custom adjustable temp relay circuit.

While you're at it, eliminate the pressure bottle, go to a regular overflow bottle.

There have been about a million writeup on this work.

http://www.google.com/search?q=site...s=org.mozilla:en-US:official&client=firefox-a

1. The sensor in the radiator is more of a switch for the aux fan.

2. You can use a 92+ thermostat housing to get an extra port.

3. You can purchase an inline sensor port for the radiator hose or the heater hose--summitracing.com or Hesco.

4. Where ever you relocate the sensor/switch to, you may actually have to use a different sensor/switch--the on/off temperature where it was in the radiator is going to need to be different if located in the t/housing or a hose.

5. And you will need an overflow bottle, the pressure bottle won't work as you need atmospheric pressure on top of the coolant.

The various links you find on the Internet, which instruct you to use the 92+ fan "switch" are wrong. Do not follow thest tips. The 92+ uses a temperature sensor (thermistor) to tell the ECU what the temp is. Then the ECU will switch the fan, based on this information. If you do this, you may or may not get enough current to hold a relay. The results would be unpredictable.

There are many threads on the Internet recommending a replacement switch that will fit into the 92+ thermostat housing. Some recommend a Corvette switch and many include part numbers. These are viable alternatives. I could not go this route with my last RENIX radiator swap, since I already had a sensor for a digital temperature gauge in this port. Use of a T fitting on this port is also not an option, since that would move both sensors out of the coolant flow.

You do not need to "relocate" the fan switch. Assuming you bought a radiator with brass end tanks, all you need to do is cut a hole in the back of the end tank, right where the hole was in the old RENIX rediator. The factory RENIX radiator has a cast iron threaded bung soldered into the tank. The switch screws into this. I used a MAP gas torch to sweat out the old bung and solder it into the new radiator. You need to be careful cutting the hole, because with an AW4, the ATF cooling reservoir sits inside this end tank about 4/10 of an inch inside the tank. I cleaned the tank and drew the circle with a Sharpie, then drilled a ring of small holes. I connected the holes with a cylinderical bur bit on a die gringer. You do not need to screw with any hoses or adaptors to do this. I used the renix presure bottle as a overflow bottle. I just screwed a small hose fitting into the bottom bottle hose fitting and connected it to the port at the cap. If you go this route and already have the tools, the cost is zero dollars.

I just thought I would add that there is no room to use a nibbling tool here, with the ATF cooler in the way.

MoFo said:

You do not need to "relocate" the fan switch. Assuming you bought a radiator with brass end tanks, all you need to do is cut a hole in the back of the end tank, right where the hole was in the old RENIX rediator. The factory RENIX radiator has a cast iron threaded bung soldered into the tank. The switch screws into this. I used a MAP gas torch to sweat out the old bung and solder it into the new radiator. You need to be careful cutting the hole, because with an AW4, the ATF cooling reservoir sits inside this end tank about 4/10 of an inch inside the tank. I cleaned the tank and drew the circle with a Sharpie, then drilled a ring of small holes. I connected the holes with a cylinderical bur bit on a die gringer. You do not need to screw with any hoses or adaptors to do this. I used the renix presure bottle as a overflow bottle. I just screwed a small hose fitting into the bottom bottle hose fitting and connected it to the port at the cap. If you go this route and already have the tools, the cost is zero dollars.

Click to expand...

Yet, that sounds like an awful lot more work than putting in an in-line (in the radiator lower hose) bung adapter. Especially if one doesn't have all the tools or know how or willingness to go cutting holes in new radiator.

Granted that would be the cleanest way, but the hose/bung adapter is sooooooo much easier, and if you replace the radiator again, it goes with the system.

I just put my fan on a switch in the cab, (driver operated fan) and no, I NEVER forget to turn it on when needed. Just 2 wires and a switch.