comanche91
NAXJA Forum User
- Location
- Sweet Home Alabama
I have been wanting to dump the antiquated mechanical fan for a while now on my MJ, and have been looking at various "how-to's" on Dino's and Gojeep's websites, among others. One criterion I had was that I wanted to keep it restorable if I ever wanted to go back to the mechanical fan, so I did not want to cut the existing mechanical pulley shaft as Gojeep did, which was necessary for clearance using the large 16" fans. After looking at various installs, I decided to go the route Slo-sho did and replace the mechanical fan with another XJ/MJ OEM electric aux fan, but with a few mods. These fans pull a lot of air for their size and I had a couple of spares readily available. Step one of course is to remove the radiator and the old mechanical fan blade, shroud, and clutch. Then I replaced the fan pulley studs with 5/16" x 24 x 3/4" bolts for added clearance as shown below.
I used the bottom radiator brace for mounting the new fan. In the pic below, in order to make the new aux fan fit and clear the mechanical fan pulley, I had to Dremel two new slots in the radiator bottom support plate to move the fan closer to the radiator, and about 2" toward the driver's side so the fan blade head would clear the pulley bolts better.
This setup fits great, and the new aux fan shroud is very close (but not touching) the radiator which increases it's efficiency. Here's what the fans look like on the rad before mounting looking from the inside out:
After mounting, although it's hard to see, I have about 3/8" clearance between the pulley bolts and the new fan head. It's enough, but I will replace the hex head pulley bolts with lower profile button head bolts as soon as I can find them for a little added clearance.
Here's a back view of the two electric fans.
And a front view.
I used a Spal variable speed controller to independently control the new fan only, which is now my primary cooling fan. The LO speed is set to come on a 190*, and the HI speed at 215*. So far these settings are working fine, with the new fan staying on LO most of the time. The existing aux fan still operates as always, ON with the A/C or when the temp reaches 220* or so. But I did want redundancy just in case, so I wired in a dash switch so I could turn this fan on manually if the new primary fan went belly-up.
So far all is well, the new fan runs 90% of the time in LO, only coming on HI speed when stuck in traffic for some time. The existing aux fan has never come on (except when I run the A/C of course. I also have noticed a mile or two increase in MPG on the stroker, which helps. The engine seems to spool up faster too w/o because it's not pulling the old mechanical fan, but this may be my imagination. And changing either fan is now a 15 minute job. Hope this helps someone who is considering doing this mod.
I used the bottom radiator brace for mounting the new fan. In the pic below, in order to make the new aux fan fit and clear the mechanical fan pulley, I had to Dremel two new slots in the radiator bottom support plate to move the fan closer to the radiator, and about 2" toward the driver's side so the fan blade head would clear the pulley bolts better.
This setup fits great, and the new aux fan shroud is very close (but not touching) the radiator which increases it's efficiency. Here's what the fans look like on the rad before mounting looking from the inside out:
After mounting, although it's hard to see, I have about 3/8" clearance between the pulley bolts and the new fan head. It's enough, but I will replace the hex head pulley bolts with lower profile button head bolts as soon as I can find them for a little added clearance.
Here's a back view of the two electric fans.
And a front view.
I used a Spal variable speed controller to independently control the new fan only, which is now my primary cooling fan. The LO speed is set to come on a 190*, and the HI speed at 215*. So far these settings are working fine, with the new fan staying on LO most of the time. The existing aux fan still operates as always, ON with the A/C or when the temp reaches 220* or so. But I did want redundancy just in case, so I wired in a dash switch so I could turn this fan on manually if the new primary fan went belly-up.
So far all is well, the new fan runs 90% of the time in LO, only coming on HI speed when stuck in traffic for some time. The existing aux fan has never come on (except when I run the A/C of course. I also have noticed a mile or two increase in MPG on the stroker, which helps. The engine seems to spool up faster too w/o because it's not pulling the old mechanical fan, but this may be my imagination. And changing either fan is now a 15 minute job. Hope this helps someone who is considering doing this mod.