So..... fan clutch SEEMS to pass the usual tests. Has some resistance at op temp. Only turns 1/3? Maybe 1/2 turn when spun by hand. Kinda hard to get a good spin on it by hand though...

Lately been running a bit hot at speed with AC on. 90 deg / 75 mph, temp gauge climbs ever so slowly till I just **** down the AC. I can run at lower speeds with AC on without issue. Say 60 mph.

Fan does not roar like folks talk about. It does seem to vary in RPM with engine as it should...
When engine is **** down it doesn't appear to spin excessively long....

Hate to throw $45 at it if it's not the issue...

What say you??

 

Lol when your phone auto corrects shut to ****.... lmao

 

How hot is "a bit hot"? Whats the temp? Is the auxillary fan coming on?

 

Aux fan comes on. It gets to 230? Maybe a bit more. When it gets close to the white line before the red I shut down AC. Dunno if it would hold there or keep climbing. It takes about 20 miles at 75mph / 90 deg AC on to get there.

 

Have you ever replaced the clutch ? It is a maintenance item. So with ac off there's no issues even during long runs ?

 

I have not. BUT I picked up this XJ in Jan and clearly it's a work in progress. Without AC on I can bomb down highway at 75-80 mph with no issue. Barely creeps over 210 and holds steady. At non interstate speeds it holds just under 210.

 

1996 could have the 5 blade aux fan a 1997 and newer has more blades and pulls more air just need to splice older plug to newer fan instant up grade. ? Sounds like aux fans getting week. Replacing clutch fan and aux fan should be on the to do lst .

 

 

The only test that is reliable is to remove the fan clutch, turn the spring 180° so that the clutch is locked up, reinstall it and see if the problem stops. The other tests like trying to spin it or sticking a newspaper in it are not entirely reliable.

That's not the fan clutch. The symptom of a bad fan clutch is that the temp is fine at cruise speed but starts climbing at idle or when moving very slowly, like when crawling or in slow traffic. That's the opposite of what you described.

When you're sitting still, the fan needs to be locked to the engine to pull air through the radiator. When you're driving down the highway, your motion through the air pushes enough air through the radiator to cool the coolant. The fan is not needed then, so the fan clutch lets the fan freewheel so that it doesn't rob power from the motor. Even if your fan clutch is not locking up properly, it will make no difference at highway speed because you have more air flowing through the radiator than the fan would provide. You'll only notice it when you're sitting still.

Time to start looking elsewhere.

 

This seems to be a common issue all of a sudden.

Is anyone else noticing this? This is the second time this week someone is having this problem.

 

Lol, because its finally summer

Sounds like a coolant flow issue to me, either water pump, plugged up radiator, or something along those lines (if it runs hot at 75mph, which is higher RPM for the water pump and ample airflow for the rad)

If the fan clutch is factory, I would just replace it. They only last ~200k miles if you are lucky anyways (IMO)

 

Like stated, its not the fan clutch.

Waterpump or radiator if I had to guess. Whats the condition of your cooling system? A good thorough flush might help out.

 

I used to think, just do a cooling overhaul first and see if that fixes it. After going through head problems and realizing I threw a lot of money at the cooling system without actually fixing the issue, I'd take a different approach.

If this were mine, first I'd try doing a thorough flush with some Prestone cooling system cleaner, since that's relatively inexpensive. Then I would try to rule out a blown head gasket before spending any money on parts. I would borrow a leakdown kit and a combustion leak test kit from one of the auto parts stores with a tool loan program and make sure I didn't have exhaust gases escaping into the coolant and heating things up when the vehicle is under load.

If those tests don't indicate a combustion leak, THEN I would start spending the money on a cooling system overhaul. The vehicle may in fact need it. But what you don't want to have happen is overhaul the thing without actually fixing the problem, then have your system fill up with crud again from boiled coolant and destroy a new water pump.

 

Lol well... that just it. Everything else checks out and the fan clutch is the only thing I was left to consider. Water pump is less than a year old. Hoses are new. System was flushed a month ago. Fluid is perfect in color. No loss of coolant. Oil has been tested by blackstone. Running Rotella T4 10w-30.

Rad COULD MAYBE have some blockage. BUT I doubt it considering when I did flush I got no miss colored fluid, sludge, or anything other than clean coolant so.... in my line of thinking that left fans?? When aux fan kicks on its loud and SEEMS to be doing its fair share??

 

T stat was replaced at last flush. Super Stant 195