HD (Heavy Duty) Fan Clutch Upgrade

[Mudderoy]

I recently upgraded my fan clutch from a stock fan clutch to a Grand Cherokee fan clutch. It is NAPA part # 272310. It was about 43 with tax.

I started by removing the bolts holding the mechanical fan shroud.
I pushed the shroud back to wards the fan and the clutch. This gave me just enough room to remove the nuts holding the fan and the clutch.



After removing the fan and clutch I laid it next to the new heavy duty clutch to compare. You can see the diameter of the heavy duty fan clutch is quite a bit larger.



Hard to compare, so I removed the fan from the old fan clutch.



Now to compare the height, this is the really important part since wider, taller, etc.. means closer to the radiator. As you can see there isn't that much of a difference.

Installation was easy. Mount fan to new fan clutch, then put the fan (AND SHROUD) in and put on the four nuts and tighten. I used a big long flathead screwdriver to hold the fan pulley in place while I tightened the nuts.

Now for the test drive.



After about 5 minutes at 75 to 80 mph on I-10 coolant temps rose above the favored 210. Air temp was in the high 90's, 97, or 98. My "prior to the HD fan upgrade" test drive I was only able to drive for about 3 minutes before hitting the first hash past 210, 222.5 degrees. So this was an improvement!



When I exited to turn around and come back down I-10, I pulled over to get a better picture of the temp gauge. This is more of a head on shot, so you get a better idea of the temp. I'm mid way between 210 and 222.5. So about 215/216 degrees.

The A/C feels cooler and the Jeep's performance is snappier. Before when it would get over 210 degrees you could feel it get slightly sluggish.

Now I have to stress that this upgrade was done on a 1998 HO 4.0L engine. From what I have read there may be some space limitations on the Renix XJ models. I would recommend taking the bolts off your shroud and then putting the new HD fan clutch next to the old to verify that you'll have the room to install it, otherwise you may have to remove your radiator, mount your HD fan clutch and reinstall the radiator.

I did not, I had plenty of room.

The HD Fan clutch is supposed to turn 70% to 90% of the shaft speed, as opposed to the 60% to 70% of the OEM XJ fan clutch. The one NEGATIVE thing I can say about this is that the clutch SCREAMS past 2800 rpm. I'll get a video and post it up here soon. With the exhaust, mudders, and stereo on it is hard to hear. My main concern was something was going to come apart, but after checking all my bolts I'm not concerned and I don't mind the scream as much.

[Mudderoy]

I installed this last Friday. Monday morning my coolant temps were normal. 210, or just a hair below. Outside air temps low to mid 80's. The drive home in 102 air temps, coolant temps were 215/216, but the A/C was colder and performance was snappy. I think the increased air flow over the condenser was helping the A/C's ability to cool. I had seen a 4 to 5 degree rise in the air temp coming from the center vents when the coolant temp would get into the 215 to 222 range before. I'm sure this means the new transmission cooler was cooling the transmission fluid better as well, but I'll need to install a tranmission fluid temp gauge to be sure.

Tuesday morning, same with the 210, Tuesday afternoon was partly cloudy so air temps were a few degrees cooler. I was closer to 212/213 and I was ahhh exercising the Jeep pretty good. Very pleased.

I have a FlowKooler water pump that should be delivered Friday. It has higher flow at low rpm and normal flow at 3500 rpm and higher. I am very optimistic that with the higher flow water pump I will be able to keep the coolant temp in the 210 area in 102/103 air temps. I believe I'll be going back to a 195 degree thermostat. In the morning (durring the summer!) it takes about 10 miles for the coolant temp to get to 210 driving 40 to 50 mph. When outside air temps start to dip in the fall and winter I'm going to be cold for a very long time waiting for the heater to warm up!

Now this doesn't address why I have to use non-stock parts to obtain the 210 temp, but if it gets me another 150k miles out of the motor, I'll be fine with it.

BTW, My first water pump choice was the Hesco, but at 169 it was just more than I wanted to spend. If you are going to get a high flow water pump I would take a close look at the Hesco.

[quadracer0387]

note: if you have a 3-row radiator, make sure your motor mounts are fine and test fit before running the engine...

[BlueXJ]

Muddy you never gave a price for the FlowKooler pump and a source.

[Mudderoy]

Originally Posted by quadracer0387

note: if you have a 3-row radiator, make sure your motor mounts are fine and test fit before running the engine...

New, about 2 years old, but a very good point for others.

[Mudderoy]

Originally Posted by BlueXJ

Muddy you never gave a price for the FlowKooler pump and a source.

Sorry I did that in another post. 114+ shipped from Quadratek.

[offroadman83]

I have a renix model motor with this fan clutch. It cured all my problems with overheating. I have a 3 core radiator csf model as well. Without the fan clutch I was always hitting 220+ which was uncomfortable to me. Most of the time worse. Now even in the 101+ weather here I just do hit 210. I even ran my mj without ac (broke for a while) so no electric fan and I had no problems at all. Well worth the money-------------Kyle

[Melissa]

Originally Posted by offroadman83

I have a renix model motor with this fan clutch. It cured all my problems with overheating. I have a 3 core radiator csf model as well. Without the fan clutch I was always hitting 220+ which was uncomfortable to me. Most of the time worse. Now even in the 101+ weather here I just do hit 210. I even ran my mj without ac (broke for a while) so no electric fan and I had no problems at all. Well worth the money-------------Kyle

So it fit right in with no problems or modifacations??

[offroadman83]

We did have to loosen the top radiator mounts and tilt it ever so slightly. Thats it though. Was a tight fit gettin in there but its got plenty of room once its in there. Having the thicker 3 core made it a little tougher

[Melissa]

Originally Posted by offroadman83

We did have to loosen the top radiator mounts and tilt it ever so slightly. Thats it though. Was a tight fit gettin in there but its got plenty of room once its in there. Having the thicker 3 core made it a little tougher

Thanks, I wanted to put this fan clutch into my jeep, but I don't have the know how if It calls for mods on my 93. I do not have a 3 core radiator on ( I did buy one though ) instead right before I bought the 3 core I had a brand new OEM radiator installed. I will go ahead then and get the fan clutch, then hit you up if I have any questions about installing it.