This is an 02 SR5 4x4 w/ 85k miles. I just purchased it on Friday. The other two (96 & 98) I've owned never did this, just wondering what's going on?

 

You need to replace your fan clutch. My 02 did the same thing, I picked up a fan clutch at autozone for $120 w/ a lifetime warranty, installed and its been fine for over 2 years now. Some say you can repack the original w/ silicone or something like that, but to me a new one w/ lifetime warranty made more sense. The job is incredibly easy, remove the 4 bolts, take off the fan, attach to new fan clutch and reinstall, you do not have to touch the belts at all.

 

awesome, thanks

 

It is normal for the fan to run all the time. When the fan clutch is cold the fluid is very thick and turns the fan at full power. When the fluid warms up it gets thinner and delivers less power to the fan, but the fan still turns.

 

I think its the opposite. It would make no sense for the fan to operate in the manner you have described as it would cool a cold engine and allow a hot engine to overheat. IIRC its some weird silicone-based fluid that gets thicker when heated.

 

Mine runs at full rpms when the engine is completely cold. It slows down after about 45 secs or so then responds accordingly to temp. I have noticed that it seems to be more sensitive than it used to be. I thought when the clutch was going out it would not allow the fan tot tuen the speed it should resulting in overheating. Not the other way around.

 

How much resistance do you feel at fan? Ex: When engine is cold and attempt to turn fan bade, this should be fairly easy at this point as clutch should be engaging. Next run vehicle until normal operating temp is reached at which point fan clutch should be deactivated. Turn engine off and again attempt to turn fan blade with hand. More resistance should be felt. If resistance at the two different intervals feels the same, your fan clutch is experiencing problems. The fan should have a much more noticeable drag to it after a full trip cycle.

 

well if anything you would be overcooling and sacrificing some MPG. i'd rather sacrifice that rather than an engine.

 

MAKE SURE the motor is off when you do this. Don't want any lost fingers.

 

Thats what mine does. it ROARS when I first start it in the morning.

I've stopped the fan with my hand/fingers before while the engine is running and never lost a finger. Why I did it? I do not know. Honestly just curious.

 

^ lol.

 

Baha, well played good sir. I'd just never chance it.

 

so what's the general concensus here on when the thing is supposed to run? seems like we've got conflicting opinions.

there has got to be something wrong with it, since it NEVER shuts off, and i've definitely had it at full operating temperature. i'll go out and check the resistance on it.

 

You're right, I got it backwards.

 

Keep us posted.

 

It should run at engine speed when idleing, as the motor speeds up, it should drop out, something like 1700-2300 rpms. I think.

 

I already told you, replace the fan clutch. It is a belt driven fan and therefore will always spin, but the clutch kicks in and it takes less power to run the fan. When your fan clutch is inoperative you are losing a good 10 -20% of your power. I went through the exact same thing with the exact same year and model truck. When you do finally get the new one you will be amazed at the difference in power, it sounds crazy but it's true. Those are the facts, if you want to let more people weigh in with what they think please feel free, its your money going out the window in lost MPG.

 

take it easy, i wasnt doubting you. i ordered it right after you posted the first time. i installed it about 2 hrs ago and i agree the power is much nicer to have back now.

thanks for the help.

youguysdaman

 

Sorry, I didn't mean to be a jerk, I guess I could have worded that second post differently. I am glad you got it sorted out though, it really is amazing how much power that fan robs. I would do an electric fan swap but I feel a properly working belt driven fan is the most reliable choice.

 

I've held many with my hand while setting timing on a variety of cars for decades. Just make sure nobody hits the gas while your holding it.

I've also hand my hand very badly cut up from a non clutched flex fan as well.


Anyway, the fan clutch is really there to pull air to cool the engine when you are idling and standing still or barely moving really. It should get warm pretty quickly on a cold engine and should not rev up with the engine when warm.

If it's frozen up it'll cost mileage and power. But make sure someone didn't replace it with a non clutched flex fan.