Mech Fan upgrade for your 5 blade TJ (Mods on a Budget)

[Air the Flatlander]

Those of you with jeep TJ's, especially those pulling an off-road trailer, here is an easy mod to upgrade your cooling system.

Those of you with the TJ's, compared to jks etc, may have noticed your temps are high. Especially when pulling your trailer. Chrysler equipped our jeeps with a lackluster 5 blade fan, which honestly is no where near enough to pull air through you already hot running 4.0. A 7 blade was offered from the dealer (if you knew about it) for a short while, but that has been discontinued for a few years.

There are a couple solutions, one being go electric, and two being upgrade your mech fan.

A simple solution surprisingly is throwing a Ford fan and fan clutch from a 1993 Explorer in your jeep. Sounds crazy, but it's literally a direct fit. The factory fan clutch in the Explorer is much better than the jeeps, and its fan consists of ten or nine blades (depending on which you select) which is a huge upgrade from your 5 blade stock jeep fan.

To do this mod is simple:
-Order a new or used 1993 ford explorer cooling fan and clutch assembly. I chose a severe duty clutch and ten blade fan. NAPA was able to get them for me next day. (Grab the bolts too from your local hardware store to attach the new ford fan to its new ford clutch, jeep ones aren't quite right)
-remove your coolant overflow tank, and if you have a factory fan shroud, unbolt it.
-blast off the large nut which attaches your jeep fan clutch assembly to your waterpump. Most garages have an air powered tool that bumps it off effortlessly. I don't own this tool since I'd use it once or twice in a ten year period. I simply drove down and they popped it off for me. Originally I tried the chain trick to unbolt it, but after being on there since 2005, it wasn't moving.
-once that's off, lift it out along with your fan shroud.
-test fit your new fan with the shroud and check clearances. Our jeep has a two piece shroud to help speed up access on the trail, we did have to trim a little. I have heard that for some people they did not need to trim.
-tighten it all, use as much of the shroud as you can, throw your overflow tank back on and enjoy the benefits.

You will throw more air, we dropped temps about 8 to ten degrees. For about 100 bucks.

I'm not a fan of elec fans. But that's another convo. So here's a good option for all of you.

 

[shortbus4x4]

Wow, this and your roof rack seem like so last century. Nice to see the old flatfender spirit of junkyard upgrades is alive and well.

 

[Air the Flatlander]

********. Got to keep it alive!

 

[Zeep]

Have you noticed any increase in noise level with the upgrade?
Most people don't realize that the 4.0 is designed to run at 210'F give or take a few degrees.

 

[Air the Flatlander]

We run a long arm kit on our tj, so our exhaust is pretty short and loud. Occasionally it's loud at start up for a few. But while driving we haven't noticed it much at all.

The 210 is fine, but when pulling an offroad trailer it's nice to actually keep it at 210. It heats up fast, and with the 5 blade, does not cool well. So it's nice to turn the ac on and not worry your going to overheat. Also blows more around the engine compartment to help keep sensors cool. Sine the high heat and heat soak usually leads to their death over time

 

[SilicaRich]

I don't pull a trailer but my 4.0 likely works harder than most with my extra weight from bumpers, winch, and other accessories making it run hotter than I would like but nothing too excessive. I noticed it most when totally loaded down for a trip to Big Bend, luckily the closer we got to Big Bend the colder air temps got which helped counter the issue.

I think I'll seriously consider this mod, also in favor of a mech fan rather than an electric. My other option is a hood louver but I'm fairly opposed to cutting a massive hole in my hood or spending $800 for one of AEV's fancy vented TJ hoods. Sub'd for the future

 

[Air the Flatlander]

I have heard that the engine comparement to release heat to efficiently as well. So the louvers help get that heat out, to prevent heat soak. But the fan seemed to be the bigger issue.

The 7 blade fan they came out with was much better. But they are super hard to find now, and no longer avail. The 5 just doesn't cut it

 

[jscusmcvet]

I have heard that the engine comparement to release heat to efficiently as well. So the louvers help get that heat out, to prevent heat soak. But the fan seemed to be the bigger issue.

The 7 blade fan they came out with was much better. But they are super hard to find now, and no longer avail. The 5 just doesn't cut it

I appreciate this info. To me the one failing of the 4.0 is that it is difficult to keep cool under heavy loads, aka trails, towing, etc...

 

[Air the Flatlander]

Sorry I was typing on handed last night due to a dog bite. What I meant to say was. I have also heard of people doing the louvers to help with heat under the hood. Since the jeep hoods really don't leave anywhere for the heat to go. This helps drop temps which usually cook your sensors etc, from heat soak.

From what I have read the, the bigger contributer to high thems, in already a high op temp jeep was the 5 blade fans. Chrysler knew there was an issue as well, hence their 7 blade which they made avail for a few years