ITS GOT A NAME!!! - I call it the FFF Mod -
Fixed Flex Fan.
Some of you may have followed this a little on the thermostat ideas topic. I have now got the setup created, so I started a new topic for this:
Heres the basic background. The fan clutch design on the CRD's seems to wear out rather quickly. In fact, the fan clutch on many of the CRD's has gone out, and most of us didn't have any clue until we went up a hill or towed for the first time in awhile and started running a little hot. Then you either baby it home or are stuck in the middle of nowhere and a replacement part has to be ordered.
Here's my solution:
I just put on the new flex fan and adapter setup I came up with. had to make a spacer (machined 2 1" washers out to 31 mm to allow clearance of fan blades - were too close to accessories). It looks sweet and DEFINITELY moves a lot more air than the factory fan/clutch even when it was locked up.
Definitely louder than a stock fan/clutch that is not locked, but sounds pretty mean and powerful. About the same noise as a fan and clutch thats locked up, a little bit of a smooth whine at high rpms, loudest at 3k rpms, starts to flex at 3K RPM's, probably half flexed at 4K rpms. Quites down a bit from 3k as it reaches towards 4k rpm peak.
I probably should have taken some photos out of the car, but here it is installed. It weighs almost exactly half the weight of the factory setup and is MUCH less rotational mass since it is not as heavy at the outer area of rotation either. All the mass in the flex fan/adapter is very close to the center of the rotational area so it will be interesting to compare economy on this next tank. I am hoping the greatly reduced rotational mass economy gain will outweigh the small loss in economy that will occur due to the fan having a direct connection and not on a clutch setup.
If you tow or are worried about staying cool, this will definitely move much more air and be more reliable than the fan/clutch setup and IT WILL NEVER GO OUT. Most fan clutches on all our jeeps already have (mine was out since I purchased the vehicle at 78K miles). I didn't even know mine was toast untill I pulled it out and found that after a couple turns with my hand it moved freely. This seems to be the case with most of us...we find out when we tow or pull a hill that it was already bad.
After an oven test of 220* and an hour later it still failed and did not grip any different than when cold. It would rotate completely free after a few turns, and could be spun and spin several rotations freely. Thankfully our jeeps cooling system is fairly robust and in the past I only had one issue getting a little hot, even with a bad fan clutch. That is why I wasn't sure it was bad until it was removed and tested.
Anyway, a new fan clutch (just the clutch) is $142.00 from Jeep plus shipping and may go out again in several thousand miles. The problem is you may not know it is bad until you are going up a hill or towing and start overheating as was my case. This setup comes in at the $100.00 mark including, the Flex fan, the spacer, the adapter, and all hardware and will not go out again. Here is a profile view:Part numbers and prices to complete the kit:Flex Fan - Imperial Part number 223619 - 19" reverse direction High flow flex fan(Advanced auto - free shipping from local store - $28.99):Adapter - Flex-a-lite part number 851 - 30 mm x 1.5 pitch flex fan adapter (Amazon.com - $43.07 - free shipping):Washers (used as spacer to allow clearance between engine accessories) - McMaster-Carr part number 93849A112 - (2 needed) (mcmastercarr.com - $4.58 each-2 needed plus shipping cost): NOTE!!! These washers you won't be able to get from your local hardware store, not a normal size. Our ace hardware, lowes, home depot did NOT have them.*EDIT* Just a note: any 31mm washers will work, thickness should be around 3.5-4.5mm thick per washer and need about 2 depending on thickness. The following part numbers will work, but are either not stainless steel or are larger outside diameter (will stick out more but still function fine) than the earlier mentioned part number: 91166A340, 91455A220, 98035A112, 93475A350.
You will also need 4 bolts and 4 lock washers to fit the spacer found at local hardware store. Total cost about $100. Cheaper than a fan clutch alone.