The only thing u check/ask yourself regarding the fan clutch is "how old is it"....if u don't know, think no more.....replace it.

 

With engine off, spin it. It should only go about 1/2 rotation or so. Maybe less. You will feel resistance.

Any more than that, it's bad. Replace it.

 

.....but that won't tell u at what percentage efficiency the clutch is performing at when the motor is running.....however, a new clutch is most likely performing at 100% efficiency, no?.

 

Ive done this before and it is pretty stiff. I only get that 1/2 rotation out of it. I put an efan on it and come to find out that it only comes on when the AC is on. But also I crammed a hose in the radiation and blew water into it and it hasnt seemed to come up past half and I peeled around in the mojave dessert all day yesterday. On the way to school today it got up above half but nothing to scary.
Maybe radiator? I also think its time for my 33's cause I lost a tire yesterday

 

wont let me start a new thread says i dont have permission Have been fighting the typical XJ overheating issues, first thing done was go through what was there new clutch fan, found raidator shroud, already had a new radiator, water pump ect> Cooling fan not coming on tried to trouble shoot everything, Finally just built a relay system and put a switch in themostat housing now it doesnt overheat fan comes on and brings temp back to 200 The problem is I was working from a old schematic, on a 1993 cherokee the sensor both sides go the the EC and the EC is what turns on the relay for fan, would leave it like this but apparently the temperature sensor info is also used to tune the air fuel mixture. So now it with sensor just unplugged it doesnt run so well in mornings So have to start over, have a junk yard EC to try this week end, so frustrating now that cooling is resolved not sure what else to try The sensor when I unplugged it when all the stock stuff was hooked up would cause the fan to run. But EC must have a problem reading input from sensor Labor day project, start with EC but wish i had more options

 

^^^ Why don't you learn how to start a new thread rather than clutter up this one?

Questions for your new thread: What year model? What is an "EC"? What temps were showing when E-fan wouldn't come on? (E-fan doesn't come on till somewhere around 218*). Temps confirmed with an IR thermometer?

 

Yes.
All viscous fan clutch testing methods out there on the net mean nothing (except maybe to very extensive and therefore unhandy test method described in the FSM with drilling holes and measuring temps).
The part is not expensive. Just replace when there is ANY doubt about it.

 

When I flip on my A/C in the summer the fan pulls so hard it sounds like a truck. As good as the FSM test as far as I'm concerned!

 

......and u know what to listen for (motor running, fan spinning sound test), and my guess is, most folks don't. For most folks, spendy the +/-$35 for a new fan clutch is a reasonable safe bet, no?

 

Soooo I replaced the waterpump and it worked well for about 3 days...not leaking anymore but still didn't know what to do. I replaced the Tstat today and put a new housing on it cause I broke it and then suddenly I get a check engine light and it still overheats?!? The top radiator hose isn't getting hard and it's still overheating....what do I do? Radiator next?

 

make sure your bottom hose isn't collapsing!

If you lost a lot of water or changed water pump you may need to bleed water system to get out trapped air!

 

Sounds like u r almost out of cooling system parts to replace so why not drain the cooling system one more time and finish off replacing all of the remaining cooling system components. If u don't correct your overheat now, 33's will likely kill it.

 

the rad is one of the most overlooked items in the cooling system, and the most problematic part to fail without you knowing it ... they clog up over time and cause alot of cooling problems ive seen a bunch more threads just like this one and 75% of the time thats the culprit.

 

I had similar symptoms to you. Coolant reservoir puking because the coolant was boiling.
I replaced my radiator cap and it fixed it.
If the cap is knackered your coolant system isn't pressurised and the coolant boils at a lower temperature.
The bonus is that it's about the cheapest part available for a Jeep.

 

Yep and that was the problem...radiator. I didn't think that it was because of the problems that the water pump had had and the thermostat was cheap so yeah. Thanks a lot guys! I'll be around XD