Fan Clutch Reverse Rotation

I just got my new fan clutch and it is stamped "Reverse Rotation". Is that right and what does it mean?
Thanks,

That is right,your water pump should be labled the same-
Wayne

OK, thanks, any reason why? I mean does a 4.0 turn in a reverse direction or the accessories turn backwards or what?
I just put a new water pump on and it wasn't marked "reverse" but it seems to work OK.
This doesn't matter I'm just curious. Is their some 4.0 stuff that isn't reverse?
I mean it seems to me to have a "reverse" there should be a "regular" if you get my drift.
In 50 years of working on engines I've just not seen this before.

Somewhere on the Waterpump was an "R" which indicated that it was reverse rotation.
Yes the V belted version of the 4.0 was the opposite rotation for the waterpump and fan clutch, as was the 258 which preceeded it but several parts suchas wp will interchange as far as bolt pattern are concerned thus the need to differentiate between the two. As you know or have probably read the 258 head and crank will also fit in a 4.0 so wil many parts but many of those engines are getting a little scarce. Parts houses which often re-build things need to know from which version of the engine things originated. Hope this clears up the question about your fan clutch.

Thank you very much. I learn so much here every day. Even though my trail rig is a 69 CJ5 I'm so glad I bought my XJ for a daily driver as it put me in touch with . I have found to be a really great bunch either on line or on the trail.

tgregg said:

Thank you very much. I learn so much here every day. Even though my trail rig is a 69 CJ5 I'm so glad I bought my XJ for a daily driver as it put me in touch with . I have found to be a really great bunch either on line or on the trail.

Click to expand...

I feel the same way and am trying to give back while I can. has helped me so much that I feel I owe someone something.
So feel free to post up anytime.

If you follow the rotation of the accessories based on the belt, CCW from the drivers side, The direction will be clear, it is all in the routing of the belt and which side the belt is on the pulley.

Is there such a thing as a 4.0 with V belts? The 4.0 came out in 1987 and as far as I know was always equipped with modern stuff like serpentine belts and MPFI.
The 4.2 had V belts but even the later ones were multi-rib (serpentine).

Re: Fan Clutch (and water pump) Reverse Rotation

tgregg said:

OK, thanks, any reason why? I mean does a 4.0 turn in a reverse direction or the accessories turn backwards or what?
I just put a new water pump on and it wasn't marked "reverse" but it seems to work OK.
This doesn't matter I'm just curious. Is their some 4.0 stuff that isn't reverse?
I mean it seems to me to have a "reverse" there should be a "regular" if you get my drift.
In 50 years of working on engines I've just not seen this before.

Click to expand...

There are several threads on the subject of "reverse rotation" of both fan and water pump in the XJ. The key thing is - which way does the fanbelt/serp belt turn the pulleys concerned?
I can't remember exactly which model-year things changed, but earlier - 1980s - Cherokees (and maybe Wranglers) had one or more belts which were routed to turn things like fan and pump in the 'normal' direction (clockwise if you're standing facing the front of the vehicle). Later XJs - from about 1990? - have a single serpentine belt which is routed around all the pulleys. Because of the way it is routed (you will notice that it loops round some pulleys with the grooved side inwards, and round others with the flat side making the pulley turn). So this means that some accessories, like the fan and the water pump, are driven in an anticlockwise ('reverse') direction.

This means that the blades of the fan, and the impeller blades of the water pump, have to be angled the right way for the direction of rotation, depending on what serp-belt routing your vehicle has. That's why you need to look for the stamped 'R' on the blades.

In the case of the water pump, the problem is that the shape and appearance of the actual pump-housing body is exactly the same, since it fits in exactly the same place. There is no marking on the outside of the pump casting (which is irritating). The 'R' is marked on the impeller inside. You just have to be sure when you get a replacement that the impeller inside it is the right one for your particular vehicle...

Hope this clarifies the subject!

br1anstorm

Were there 4.0L's with V-belts? ....... I believe so, but the 2.5L which shares the same front end accessories and form factor definately had V-belts. In general, base model units with no A/C and no power steering had V-belts. And yes, XJ's came without power steering. I had one.