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Radiator Conversion / How to Switch Fan?

Runnin'OnEmpty

NAXJA Forum User
Location
Southeast USA
I did a 3-row radiator conversion last fall. Works great. However, I don't have the aux fan installed. What is the best way to switch the fan?
1. Late model water neck with thermostat switch.
2. Manual switch in the cab.
3. Aftermarket thermostat switch that fits in the radiator hose.
4. Other suggestions?

Or is the aux fan really necessary with a 3-row radiator? Mine runs fine without it now, but the weather has been cool.....

Thanks.
Don
 
I don't know if you are sufficient without, however, I did do a 91 thermostat housing on an 89 so that a mech temp gauge could be installed. I like the even temp. increments on the 270 degree sweep gauges. The temp probe was too big for the sensor at the back of the head. The newer cover fit great and I have no prob. The stock aux fan sender may be too big for the tap on the thermostat housing. If you go this route you may need an aftermarket sender. If you need the tap size, maybe I could measure it for you. There is a site that talks about the connection of a manual switch to the fan relay. Maybe the aftermarket temp switch could connect to the same location. Part of the adress is "olyen" or something like that. Do a search for XJ electrical. I have seen high dollar gauges that actually include an adjustable switch to trigger a fan. That would be cool but who has bucks for something like that ($150)?
 
You have found the reason I don't advise people to "upgrade" to the open system -- no good way to control the aux fan. You will find that in hot weather the aux fan is necessary. However, the sender used with the '91 and newer XJs is not a simple on/off switch such as in yours, it's actually a thermometer that sends a temperature reading to the vehicle computer. The aux fan in the new ones is controlled by the ECU.

You already have the new rad installed, so having a shop cut the bung out of the old one and braze it into the new one is no longer an option. That basically leaves you two options -- a temperature switch that mounts in the lower hose or sticks in between the radiator fins, or a simple manual switch. The manual switch is a lot easier to do and gives you better control of what's happening, but it does mean you have to remember to watch your temp gauge.
 
Thanks for the replies, Tripp and Eagle. That helps.

I'll forget about the late model water neck, since the 91+ temp sender won't work, and my stock 89 thermo switch is probably too large to re-drill and tap the housing.

I could easily wire in a manual in-cab switch to the stock fan relay. I hesitate to go this route, because the wife drives it occasionally. Enough said.....:D

I've found a thermo switch in my Summitt catalog, that looks like it might work. A probe is installed in the radiator hose, and routed to a temperature adjustable box. The box then turns the fan relay on/off. The cost is about $25. I like the idea that it's temperature adjustable, so I could fine tune it.....
 
If you're refering to the thermo switch that would come with a Flex-a-Lite fan, think twice before buying it. It takes quite a bit of monkeying around with the hose, some electrical tape, and in my case some silicone sealant to get it to stop leaking. Now that that poor excuse for a cooling fan is gone, and I still have the switch installed, I'm considering rewiring it to the stock fan. I do like having a switch for it in the console though. I'll probably leave the switch in the console wired up, and wire the thermo switch back up so that if I, or someone who dosen't understand how to operate it, would forget to turn it on there is a backup.
 
Turbo City makes a kit.#640-115 Fan Switch kit.Use a late model thermostat housing and a T-fitting to have both a sender for a temp guage and a sensor to turn the fan on,splice a switch in and have manual control.
Wayne
 
You can also swith out your thermostat housing for the h.o. housing then install a kit Autozone carries in the housing,the kit is for universal applications,and is adjustable,ask a knowledgeable sales clerk for the kit, behind counter, with aftermarket fans,you will also need something to read temp to adjust your switch,all this only cost me about $60
 
Wow, I started this thread over 5 years ago! Time does indeed fly.
The 89 has since been replaced by my 'new' 96 Sport, but in hopes it helps someone else, here's what I did:

I picked up the kit from AutoZone that includes a temp sensor and adjustable controller box. It was simple to wire in, I used the existing wiring harness going to the original temp sensor. After mounting the controller box on the fenderwell close to the radiator, I attached the temp sender to the radiator side tank, so it was touching the brass and would conduct heat. Probably used a length of copper wire, zip tie, or maybe silicone, I really don't remember exactly how I attached it. (The sensor was designed to fit inside the radiator hose, but I didn't want to chance a leak, that's why I attached it to the radiator tank.)

After driving it on a hot day, and letting it idle for a few minutes, I adjusted the controller screw so the fan was just at the edge of starting. It took some experimenting by turning the fan on and off with the adjustment screw, but the adjustment was pretty good; the fan would only come on when the temp gauge would start to climb toward the middle range.

Never had an overheating problem for the time I kept the Jeep, about 3 years or so.

Thanks to all of you who gave advice on this matter......:wave1:
 
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