Oceanairbrush

I am doing an efan conversion and the wiring kit came with a thermostat sensor to screw into the block somewhere. I see one in the thermostat housing but if I disconnect it is my temp guage or factory efan going to stop working. It obviously has wires going to it for some reason. Is there another location to put it that might be open?

cruiser54

91 or later?

mschi772

What kind of sensor? What kind of fan setup? What yr XJ? Some fan controller sensors are pushed between the radiator fins. Some get mounted by the t-stat housing in the heater hose (the one going to the core, not coming from). In older XJ's the factory e-fan's switch is a sensor in the radiator tanks.

We need more information.

Oceanairbrush

Its a 94. Sorry I thought the description of "screwed in the block" negated the possibility of it being a slip in between the fins type. What kind of fan setup? Not quite sure what you mean? Its a harness I ordered off amazon and it has a threaded screw in temp sensor similar to the one on the thermostat housing.

mschi772

You said you're doing an e-fan conversion. I want to know what it is. What kind of fan is it. Does it have a shroud? The sensor/switch--what temp(s) does it turn on/off at? I suspect that the way to go will be to mount it in the heater hose with some various fittings, but without knowing more specifics about what you actually have, I'm not comfortable telling you what you should do.

There's no where I'm aware of that you can just screw a new sensor into the block for coolant temp sensing purposes without taking the place of a sensor that's already there and being used.

Oceanairbrush

That was the answer I was looking for, the last part I mean. I did order a fitting that splices into the radiator hose and holds the fitting but it seems to be way smaller than the one they shipped me and I will have to drill and tap it.

To answer your questions, it's a generic fan I got off of amazon. 1700cfm, 12" no shroud, I plan to either make my own out of fiberglass or carbon fiber using the original as a generic template.
The thermostat I chose turns the fan on at 200 and off at 185. I thought it should compliment the 195 degree target temp nicely.

mschi772

Only 1700 cfm? That's a severe reduction from what the factory mechanical fan is capable of. Be careful not to put yourself in a position where you overheat because your fan can't keep up.

Oceanairbrush

While that may be true, there is a severe difference between capable of and whats usable. When you are at idle in traffic, that fan is putting out 600-800cfm max. My electric will put out 1700. When you are driving over 40mph, the mechanical is worthless, more airflow is generated by forward movement than the fan. Its just wasting hp. My efan, is turned off. And, if I find myself in a condition where 1700cfm isn't enough, the secondary fan will kick on giving me 2800cfm. more than enough to cool it in even the most extreme conditions but if not, then I will remove the factory fan and add another 12" one for a total of 3400cfm.

Oceanairbrush

I did find something interesting though. The back of the head is the temp sending unit for the temp guage, the thermostat housing is for the efan. That said, pre-91 models had a coolant temp sensor in the drivers side of the radiator. Since most of the radiators sold fit 84 and up. I am willing to bet there is a place for me to put my temp sensor there thats not in use. I'll let you know come tomorrow during daylight.