Ok so my XJ currently has a 185 or 180 degree thermostat in it. When i drive around with out sitting still it holds the temp great, or at least the gauge says so. When i drive in town or i am just sitting in general after i get up to operating temp, the temp rises up to just past the 210 mark on the temp gauge. Does this mean the fan clutch is going out since its not holding its temp? Secondly, will replacing the fan clutch, if its gone bad, fix this?

 

The #1 cause of "temp creep" at idle IS the fan clutch.

Often overlooked, inexpensive and easy to replace.

Do it.

 

Yeah that was the conclusion i had come to, i was just looking for a conformation. Is there like a heavy duty one or anything, i havent been able to find one.

 

Fan clutch is one of the few causes. And it's really simple to do. I did mine and it took about an hour. I got the fan clutch made by Torqflo. It is a small upgrade because it is bigger than the ones that come stock. Gotta say I'm definitely happy with it

 

Usually, a "heavy duty" clutch makes for more fan noise/roar and takes more power to turn the fan which means less power to the wheels. It may never "freewheel" like it should when max cooling is not needed. Unless low/no vehicle speeds for sustained periods are the norm (ie., crawling), the stock unit should be fine.

 

Thanks, i really appreciate all this. I'm probably gonna go get one this week and see what changes i get. I think i'll really be able to see it in the summer driving around town and what not.

 

Sorry for digging this up again but will running a 180 thermostat in it cause the fan clutch to burn up faster or anything?

 

No. Time/miles slowly degrade fan clutch performance.

 

rockauto has a good price on heavy duty and severe duty clutches

 

Dont mean to thread jack but Can anyone chime in why my clutch fan constantly goes from low to high to low while and back while im at idle. Its been doing this more and more lately

 

The fan clutch is a thermal unit that senses the air temp being pulled thru the rad. At +/-170F air temp the clutch free wheels less to pull more air thru the rad. How old is the clutch?.....could be going bad. Also, r u positive the hi/low u hear is not the efan cycling on/off.

 

Im not sure how old the clutch is, i just hit 100,xxx miles, so im assuming its original. And yes im certain the mechanical fan is going at 2 speeds. It does this when the engine is even cold, hints why i'm asking. Ive watched it to see if it was the E-Fan but its not. It just continually cycles.