Fan Clutch Bad? (7 Viewers)

[ADVFJ80]

Hi all,
New odd behavior from my 1997. I live in Phoenix, and it's starting to warm up. Recently, my 80 has started to get hotter than I've ever seen. I've had a scan gauge for years, and engine temps have only ever reached 206°- even on 115°+ days last summer.

Recently, when air temp is near 100°, after about 20 minutes of driving, engine water temp gets over 220°, which I believe kicks the aircon off. Temps climb while driving, and drop while stationary, which I think is odd. Ran the heater today when temps neared 230°. Hottest I saw today was 229°. Nothing under hood appears wrong. But I can't, and have never, hear the fan kicking on or off.

Radiator flushed about 5k ago, and fluid looks great. This behavior is a new, sudden occurrence.

Sounds like fan clutch to me? It is either the original fan clutch, or a replacement. It is not a blue hub. Landtank has the blue hub in stock, and I'm ready to pull the trigger, just wanted to get some insight.

Am I missing anything?

Thanks

 

[Idaho Savage]

FWIW I had nearly the exact same symptoms and it was indeed the fan clutch. But I'm only one guy and I'm a sure it could be a variety of things. Fan clutch is pretty easy to test.

 

[LongDuck]

"Temps climb while driving and drop when stationary" - sounds more like a blocked up radiator or bad thermostat, as the engine is working a lot harder when underway than when idling.

When was the last time you replaced the radiator? What model did you use? Thermostat and water Pump known good?

The fan clutch is a good place to start, but when the truck is moving through the air, you should have plenty of cold(er) ram air coming in the grill to help with cooling. Take a close look at your A/C Condensor in front of the radiator as well as the Trans Oil Cooler on the DS. Both of these, if clogged with debris, can obstruct airflow and lead to your symptoms. While there, look past them and check to be sure your radiator isn't crudded up with dried weeds and mud from your last water crossing. It happens more than you think.

I'm still a big believer in the TYC-1918... plus foam tape to seal it to the radiator surround properly.

 

[Rwhat]

Take a rolled up newspaper and put it against the fan slowly and see if it stops the fan.

 

[landtank]

When you are seeing those elevated temps pull over, turn the engine off and check for resistance when turning the fan. There should be substantial resistance. If not it’s likely the clutch.

And the comment about having plenty of air flow at speed is false.

 

[80t0ylc]

Hi all,
New odd behavior from my 1997. I live in Phoenix, and it's starting to warm up. Recently, my 80 has started to get hotter than I've ever seen. I've had a scan gauge for years, and engine temps have only ever reached 206°- even on 115°+ days last summer.

Recently, when air temp is near 100°, after about 20 minutes of driving, engine water temp gets over 220°, which I believe kicks the aircon off. Temps climb while driving, and drop while stationary, which I think is odd. Ran the heater today when temps neared 230°. Hottest I saw today was 229°. Nothing under hood appears wrong. But I can't, and have never, hear the fan kicking on or off.

Radiator flushed about 5k ago, and fluid looks great. This behavior is a new, sudden occurrence.

Sounds like fan clutch to me? It is either the original fan clutch, or a replacement. It is not a blue hub. Landtank has the blue hub in stock, and I'm ready to pull the trigger, just wanted to get some insight.

Am I missing anything?

Thanks

I’m assuming that you don’t hear the start up roar on first start in the morning? If so, chances are it’s a bad fan clutch. Or it’s always roaring, which is just as bad because it’s seized.

 

[mudgudgeon]

Temps climb while driving, and drop while stationary, which I think is odd.

The engine is working to push that 2.7 tonne brick through the air. It's gonna produce more heat while driving at higher speeds.
A working fan clutch is essential to cool the radiator at highway speeds, you can't rely on air flow alone, particularly in a hot environment likr Arizona
Ram air is a bit of a myth until you hit speeds above what an 80 will achieve.

I can't, and have never, hear the fan kicking on or off

You definitely should hear it at times. They'll typically make some noise on start up, but also, in your scenario when it's hot while driving, then you come to a stop. Or on a hot day, sitting in traffic with the AC on, you'll hear it cycle on/ off.


Definitely sounds like fan clutch would be a good place to start looking.

 

[ADVFJ80]

I’m assuming that you don’t hear the start up roar on first start in the morning? If so, chances are it’s a bad fan clutch. Or it’s always roaring, which is just as bad because it’s seized.

No, I can't say I've ever heard what I would think is fan noise.

 

[ADVFJ80]

When you are seeing those elevated temps pull over, turn the engine off and check for resistance when turning the fan. There should be substantial resistance. If not it’s likely the clutch.

And the comment about having plenty of air flow at speed is false.

Thanks for the reply. I'll be dropping an order your way!

 

[lumbee1]

I had similar issues but when idling my temps would climb, moving temps would swing between 182 and 190. Luckily, I had a spare fan clutch. I installed the new fan clutch but when I pulled out my old one I spun it by hand and it had normal resistance. I never tested it while it was on the truck. Walking back to my garage to put the fan clutch in my Toyota spares bin and I spun it was more time and there was zero resistance and spun like it had bearings inside of it . My guess is not enough fluid in the clutch.

I'm 6'2" and still needed a ladder to reach the fan clutch.

 

[80t0ylc]

No, I can't say I've ever heard what I would think is fan noise.

Just to clarify, with a normal healthy fan clutch, on the 1st startup (rig has been sitting all night, engine off) you'll hear what is commonly referred to as "fan roar". This will quiet down as the fluid inside the clutch is dispersed. Being that it has sit for several hours, the fan clutch fluid collects to the lowest part of the clutch and this locks the clutch into the highest stage, (pulls most air, so it's also the loudest stage - where the term "roar" comes from) which is where it goes when the ambient air temp (usually above 95F) makes the cooling system work the hardest. There are several stages determined by the temp sensor, on the front, center, metal part of the clutch, that senses the air temp that the fan is pulling through the radiator and A/C condenser in front of the radiator. The clutch is adjustable inside to control when the clutch changes stages. But it looks like you're ordering a Landtank modified clutch and from my experience, that is your best choice because he does the work of setting the clutch up. I've got a Landtank clutch and it works great. I highly recommend it. The thing is, if you order a stock Toyota blue hub clutch, it needs to be adjusted. Especially if your 80 is modified adding extra weight and/or you're running in hot weather consistantly.

 

[ADVFJ80]

The thing is, if you order a stock Toyota blue hub clutch, it needs to be adjusted. Especially if your 80 is modified adding extra weight and/or you're running in hot weather consistantly.

That's pretty much the conclusion I've come about the clutch replacement itself.

Thanks for sharing the info!

 

[ADVFJ80]

I'm 6'2" and still needed a ladder to reach the fan clutch.
View attachment 3913687

This has been my experience doing anything under the hood of my 80!

 

[duece71]

Question…..
What is considered “normal resistance” for the fan clutch? I have never heard the “fan roar” upon start up from sitting overnight. With the engine stopped, I can turn the fan with some resistance but it’s not difficult. I have the orange hub from Land Tank.

 

[80t0ylc]

Question…..
What is considered “normal resistance” for the fan clutch? I have never heard the “fan roar” upon start up from sitting overnight. With the engine stopped, I can turn the fan with some resistance but it’s not difficult. I have the orange hub from Land Tank.

I see you have a diesel engine. So many things are different from a 1FZ-FE and the "fan roar" does not pertain AFAIK, to Toyota diesels. You may not even hear it due to normal engine noise. I'm not sure what "normal resistance" is on an orange hub fan clutch, but on a blue hub, it's (while the engine is off) that you should be able to spin the fan blades with your hand but you should feel resistance so that it doesn't keep spinning after you let go of it. AFAIK, there's no measurement of force, but if you stay familiar with the force needed to move a new or healthy fan, that's where the term "normal resistance" comes from.

 

[duece71]

I see you have a diesel engine. So many things are different from a 1FZ-FE and the "fan roar" does not pertain AFAIK, to Toyota diesels. You may not even hear it due to normal engine noise. I'm not sure what "normal resistance" is on an orange hub fan clutch, but on a blue hub, it's (while the engine is off) that you should be able to spin the fan blades with your hand but you should feel resistance so that it doesn't keep spinning after you let go of it. AFAIK, there's no measurement of force, but if you stay familiar with the force needed to move a new or healthy fan, that's where the term "normal resistance" comes from.

Ok, sounds good. I don’t hear any fan roar upon start up and I can spin the fan when the engine is not running. I don’t have a water temp number gauge (yet) just the OEM gauge cluster. I need to get some numbers onto my reveltronics gauge…would be nice to have and see what the temp is doing.

 

[landtank]

The diesel orange clutches have a thicker oil out of the box than the 1FZ-Fe blue hub. If you're hearing no roar on startup the clutch is shot

 

[duece71]

The diesel orange clutches have a thicker oil out of the box than the 1FZ-Fe blue hub. If you're hearing no roar on startup the clutch is shot

So pull it out and add more fluid or drain some fluid out?

 

[ADVFJ80]

Update today, as I didn't need to drive it yesterday. Before running errands (all city streets, w/normal traffic), before starting the engine, I gave the fan a spin. Maybe a blade or two widths free spool. Ambient air temp 94°.

After errands with maybe an hours worth of driving, immediately after shutting the engine off, I cannot tell a difference in the fan free spool. @landtank, I would not call it substantial resistance at all, just not a lot of free spool.

Engine temps ranged 202-207° according to the Scan Gauge.

I'm still thinking fan clutch. Radiator, a/c condenser and all other coolers are clean.

- Randy

 

[ADVFJ80]

The diesel orange clutches have a thicker oil out of the box than the 1FZ-Fe blue hub. If you're hearing no roar on startup the clutch is shot

I just updated as well. Any other thoughts on what I should check?