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Using Taurus Fan on a 2.5L

xj92

xj92

NAXJA Forum User
Location
Junction City, KS
Has anybody put in a Taurus Fan on a 2.5L? I was planning on using all the information I've read in the various threads, then I realized the 2.5L never had an electric fan at all, so I wouldn't just be able to use the stock system that turns it on with the A/C or when the engine gets hot like I had hoped (as the 4.0 engines have). I'll need to wire this up within the next couple weeks and would rather not just do a manual switch so that I have to remember when to turn it on, off, low, hi, etc. I'm trying to squeeze every last ounce of power and mileage out of the 2.5L, while keeping it low cost. I already have the Taurus fan and the mech fan is already gone. I'm also installing a radiator from a 4.0L. The whole thing is torn apart right now awaiting the rebuilt head.

PS: It's an '88 2.5L, but has '93 wiring harness, intake manifold, throttle body, sensors, etc.
 
I've got one on my 2000 2.5 I used a relay kit from Jegs that came with a temp switch, but you can get universal temp switches from autozone or any other parts place. I have the relay triggered by the temp switch after running through a switch on the dash, so it can run when it needs to and I can still kill it if I want. I wired the high speed independently on a seperate relay triggered by a switch on the dash. Generally the only time I ever turn off my low speed switch is when I want to use the high speed.

FYI, late model 4 cylinder XJ's do have an electric fan triggered by the a/c compressor. The wiring is useless though as it is not temperature controled and is too small to handle the amperage of the taurus fan. Oh, and my high speed keeps my engine at around 150*, slightly overkill...
 
If I used the kit in the link above, where is the best place to thread the thermostatic switch into? I know there's some sensor in the thermostat housing, and another at the back of the head. Anybody know what each sensor is for? I want to make sure that I can still see the temp on my interior gauge as well when I remove one for the electric fan switch.
 
yellowta said:
I've got one on my 2000 2.5 I used a relay kit from Jegs that came with a temp switch, but you can get universal temp switches from autozone or any other parts place. I have the relay triggered by the temp switch after running through a switch on the dash, so it can run when it needs to and I can still kill it if I want. I wired the high speed independently on a seperate relay triggered by a switch on the dash. Generally the only time I ever turn off my low speed switch is when I want to use the high speed.

FYI, late model 4 cylinder XJ's do have an electric fan triggered by the a/c compressor. The wiring is useless though as it is not temperature controled and is too small to handle the amperage of the taurus fan. Oh, and my high speed keeps my engine at around 150*, slightly overkill...
Click to expand...

theres a reason jeep designers want the 4.0 running at 200 deg
 
xj92 said:
If I used the kit in the link above, where is the best place to thread the thermostatic switch into? I know there's some sensor in the thermostat housing, and another at the back of the head. Anybody know what each sensor is for? I want to make sure that I can still see the temp on my interior gauge as well when I remove one for the electric fan switch.
Click to expand...

I've got a T fitting from Lowes plugged into the stock location on the thermostat housing so I can keep the stock sensor for my dummy lights.

I know 150* is too cold, that's why I never use the high speed. And it's not a 4.0 :p
 
Question 1: I have one wire left to put in for my e-fan. I need to tap into an ignition wire so it only has power when the vehicle is on. Right now all my wiring is near the battery. To keep it clean I'd like to tap into one of the wires coming out of the engine fuse box if possible. Does anybody know which wire (what color)? I have a tester but I'd rather not poke all the wires in the engine bay if I can avoid it. '93 XJ 2.5L wiring.

Question 2: When using a Taurus fan, does the low speed power need to be disconnected in order to use the hi speed? I've wired my low speed into a thermostatic switch and plan on wiring the high speed to a manual switch. Just wondering if I need a manual switch to turn off the low speed before turning on the high speed (from yellowta's post above, it sounds like it, but just checking).
 
xj92 said:
Has anybody put in a Taurus Fan on a 2.5L? I was planning on using all the information I've read in the various threads, then I realized the 2.5L never had an electric fan at all, so I wouldn't just be able to use the stock system that turns it on with the A/C or when the engine gets hot like I had hoped (as the 4.0 engines have). I'll need to wire this up within the next couple weeks and would rather not just do a manual switch so that I have to remember when to turn it on, off, low, hi, etc. I'm trying to squeeze every last ounce of power and mileage out of the 2.5L, while keeping it low cost. I already have the Taurus fan and the mech fan is already gone. I'm also installing a radiator from a 4.0L. The whole thing is torn apart right now awaiting the rebuilt head.

PS: It's an '88 2.5L, but has '93 wiring harness, intake manifold, throttle body, sensors, etc.
Click to expand...

Oh, it's you again! I'm interested in all your work, do you also have a 93 ignition on it? I'm trying to get everything together now for my MPI conversion, the electric fan install is also quite interesting!

Another guy just posted about putting a ZJ/WJ fan in his 2.5, I'm also going to follow whatever he is planning.

From what I've heard, the taurus fan is about three or four inches taller than the 2.5 radiator, I want to see whether there is much difference between the ZJ/WJ fans and the taurus fan.

Yeah, let me know what is up please, thanks!
 
The Taurus fan is a great match size-wise for a 2.5 radiator, however I installed a 4.0 radiator to open up the engine compartment some. When I first checked clearances, the Taurus fan wasn't going to fit with the 2.5 radiator in the stock location (because it sits so far back to allow the engine-driven fan to be close to it), so I simply swapped in a 4.0 radiator instead. In hindsight, it would have definitely just been easier and cheaper to modify whatever was necessary and stick with the 2.5 radiator.

So far I just have the '93 wiring harness and everything else '93ish in the engine compartment. The interior wiring is still stock '88 but will get upgraded in the future. It's more work than it sounds like because you either have to splice wires to your old sensors and hope they send the same signal for the computer to recognize it, or replace everything with the '93 era stuff which is the route I'm taking. The entire engine compartment is laid out differently also. For example, the sensors & plugs for the windshield sprayer are different, the '93 distributor has a wire that plugs into the harness where the renix does not, and several other small things I can't think of off the top of my head.

I just need to get the darn thing running again, it's been a couple months at this point.

Edit: The ideal way would be to have a donor vehicle parked next to the one you're upgrading. That would make it really simple each time you realize you need one more small part, instead of having to drive a long ways to the junkyard again or order stuff online and pay more. Nickels & dimes....
 
xj92 said:
The Taurus fan is a great match size-wise for a 2.5 radiator, however I installed a 4.0 radiator to open up the engine compartment some. When I first checked clearances, the Taurus fan wasn't going to fit with the 2.5 radiator in the stock location (because it sits so far back to allow the engine-driven fan to be close to it), so I simply swapped in a 4.0 radiator instead. In hindsight, it would have definitely just been easier and cheaper to modify whatever was necessary and stick with the 2.5 radiator.

So far I just have the '93 wiring harness and everything else '93ish in the engine compartment. The interior wiring is still stock '88 but will get upgraded in the future. It's more work than it sounds like because you either have to splice wires to your old sensors and hope they send the same signal for the computer to recognize it, or replace everything with the '93 era stuff which is the route I'm taking. The entire engine compartment is laid out differently also. For example, the sensors & plugs for the windshield sprayer are different, the '93 distributor has a wire that plugs into the harness where the renix does not, and several other small things I can't think of off the top of my head.

I just need to get the darn thing running again, it's been a couple months at this point.

Edit: The ideal way would be to have a donor vehicle parked next to the one you're upgrading. That would make it really simple each time you realize you need one more small part, instead of having to drive a long ways to the junkyard again or order stuff online and pay more. Nickels & dimes....
Click to expand...

How did you fit the 4.0 rad? I thought it sat further forward just because of the redisigned front clip only?

Is the electric fan itself interfering with the pulleys and such from the engine, or just it's shroud? The older 2.5's use pulleys that sit out further to clear the larger timing chain cover. I think I may replace all of that, P/S pump, Water pump, and get a ZJ alternator, but I would have to figure out what to do with the AC compressor.

All that to clear an electric fan though? Ehh... well I already have to replace the P/S pump, and the older ones cost more last I checked...

I exactly understand what you mean about the donor thing, but I have NEVER seen a 2.5 MPI XJ in person. I was thinking of taking a picture of a neighbor's HO (or just walking over there to look) to accomodate that need...
 
  • There's no change to the front clip on 4.0 xj's. The 2.5's just have additional plates added in to block off the empty space. Remove the plates and get 4.0 parts and it's all bolt in. The P/S reservoir mounts to one of those plates though, so you'll have to relocate that. I just used a 4.0 style reservoir that mounts to the pump instead.
  • It was the back of the motor on the Taurus fan that barely touched one of the pulleys.
  • If you replace things with the later years' stuff, you'll not only have to do p/s & water pump, but alternator, harmonic balancer, & A/C as well as all the relevant brackets. Not worth it IMO, find a different way.
  • If you use a 4.0 rad, you have all kinds of space, but you'll need 4.0 radiator hoses, which will then not reach because the 2.5 sits further back. I fixed this with two $7 radiator hose repair kits from Autozone and a foot of just straight radiator hose. I sliced the straight section of the top hose and added in about 6" of hose using the radiator repair pieces. On the bottom hose I added in about 5" of hose onto the end near the radiator.
 
Last edited:
my engine at around 150*,
========================
Using a T fitting. If a leg of the T points up and the sensor is mount in the up leg air maybe trap in that leg. This trapped air creates a "dry senor". Dry temp senors are known for being unreliable.
Also you have taken the senor out of the main coolant stream. The senor may take longer to respond to changing coolant temps. Generally not a biggy but if this tubing gets very long it MAY take a lot longer to reaspond. It may also act like a small rad dropping the coolant temp before it reaches the senor.
You know me, if theres a down side I will think of it.
 
Last edited:
I had considered it being out of the main coolant stream and the fact that the temp may be different, but I hadn't considered the trapped air, and it does point up the way I have it right now. I'll see how it works and then modify it accordingly. It's probably 3-4" away from the thermostat housing as it sits now. I guess I could get really fancy if I want to and make a pipe that I can slip the radiator hose over and drill and tap it for the additional sensor.
 
As I'm probably going to do a fan swap soon (if not when I do the header next week), I'm curious about the screw in sensors.

I've got one on the thermostat housing, and there's another on the rear of the head? Where I should be looking for this? Is it under the manifolds or in that area?

I'm looking at the Derale adjustable controller on Summit's site, but aside from changing a radioator hose and the thermostat and gasket since I had it apart, I've never had to mess the the cooling system. I'm leaning toward the screw in sensor over the radiator probe (do those really just wedge in between the fins?), but I honestly don't know where the thing would go. This tee used to add the sensor- just grab one from the Lowes'/Home Depot plumbing section with the right threads and put it in where the stock gauge sensor connects? Is that the ideal placement (assuming the leg is not pointing up)? I was thinking the same thing off the Tstat housing would work well, but I don't honestly know. I was looking at this type of controller.

http://store.summitracing.com/partd...49&view=1&N=700+150+400434+4294924500+309447+

And the option to add a manual switch is nice. No matter how badly I might screw up, I can still turn the fan on. I like redundancy.
 
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