When should the clutch fan run?

[jross20]

Continuing my quest to figure out why the engine runs at around 203-207 ° F. I had the thermostat swapped with an OEM one, made sure the jiggle valve was at 6:00. No change at all which was disappointing. So, back to square one.

Seeing as how the AC isn't working as well as it used to (refrigerant checked already), I was curious to see what the clutch fan is supposed to do. Currently as far as I can tell my own ever runs at start up for a minute or so and then quits.

Is it supposed to come on only at a specific temperature?

 

[Bad Luck]

Continuing my quest to figure out why the engine runs at around 203-207 ° F. I had the thermostat swapped with an OEM one, made sure the jiggle valve was at 6:00. No change at all which was disappointing. So, back to square one.

Seeing as how the AC isn't working as well as it used to (refrigerant checked already), I was curious to see what the clutch fan is supposed to do. Currently as far as I can tell my own ever runs at start up for a minute or so and then quits.

Is it supposed to come on only at a specific temperature?

If you are talking about the engine cooling fan clutch it's a viscous clutch. The warmer it is the firmer it is supposed to couple the belt driven portion with the fan. With a cold engine start you should be able to stop the fan with a rolled up newspaper or magazine, but shouldn't be able to do the same with the engine at operating temperature. What other cooling system work have you done? What's your outside air temperature range and humidity?

 

[jross20]

If you are talking about the engine cooling fan clutch it's a viscous clutch. The warmer it is the firmer it is supposed to couple the belt driven portion with the fan. With a cold engine start you should be able to stop the fan with a rolled up newspaper or magazine, but shouldn't be able to do the same with the engine at operating temperature. What other cooling system work have you done? What's your outside air temperature range and humidity?

Interesting, so it shouldn't ever totally stop? I'm pretty sure mine does but I'll have to check. The way it operates made me think it was activated by an electrical signal.

The radiator is new, coolant is fresh, and the transmission has its own external cooler

Temp wise, it's 80-100 at 70% + daily but the engine will run at 200 in the winter as well

 

[brillo_76]

Mine never stops.. They just spin. Colld you hear it fire up then slow down when it cooler out.

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[19963.4lsr5]

This is how much of my Rad I had to block to get it to go above 191 degrees in November.

The fan will speed up and slow down based on how hot the air is coming off the Rad.


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[jross20]

This is how much of my Rad I had to block to get it to go above 191 degrees in November.

The fan will speed up and slow down based on how hot the air is coming off the Rad.


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Assuming I'm understanding the photo, it looks like you didn't have to block a lot?

 

[19963.4lsr5]

Assuming I'm understanding the photo, it looks like you didn't have to block a lot?

No, had to block 3/4 of the Rad. That center is all that’s open.


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[19963.4lsr5]

With your engine hot and up to temp if you pop the hood and use your hand to hold the engine around 1500 or so you should hear the fan and feel the fan speed up and slow down. I know I could / can notice it (the fan) change speed charging the AC as the clutch engaged and disengaged.


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[pluton]

The Olde rules (rules can sometimes be broken):
Runs hot in slow traffic: Fan clutch.
Runs hot on the highway: Air flow blocked to radiator, coolant circulation poor due to radiator internal blockage or water pump ineffective.

 

[thegipper]

The Olde rules (rules can sometimes be broken):
Runs hot in slow traffic: Fan clutch.
Runs hot on the highway: Air flow blocked to radiator, coolant circulation poor due to radiator internal blockage or water pump ineffective.

My 97 also ran hot in slow traffic. Radiator, water pump, coolant, hoses etc were all recently replaced yet it still ran a little hot when stopped.

I finally changed out the fan clutch and since then, it never goes above 198*

 

[jross20]

With your engine hot and up to temp if you pop the hood and use your hand to hold the engine around 1500 or so you should hear the fan and feel the fan speed up and slow down. I know I could / can notice it (the fan) change speed charging the AC as the clutch engaged and disengaged.


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Alright I'll check that out after work tonight.

 

[phattyduck]

Is it supposed to come on only at a specific temperature?

It should always be spinning when the engine is running. Loosely associated to engine speed when the air coming through the condenser/radiator is relatively cool and much tighter to engine speed (loud!) when hotter air is sucked through the radiator.

All those cooling fins on the clutch are to transfer air temp to the viscous clutch internal fluid. Hotter = more locked.

As a reference, when the AC is on during a hot day, driving should sound similar to the ~30 seconds at initial startup of loud fan... and generally should get quiet once you are up to speed for a bit.

If everything is working 100%, you should basically only see temps between 185-195*F once warmed up. This is true for mine even with blasting AC on 105*F days in traffic...

How's that radiator cap? I'd get a new OEM one, just in case...

-Charlie

 

[19963.4lsr5]

How old is your fan clutch? If it’s over 100k miles I’d just buy an Asin off whoever you like to use and replace it.

Like Patty said. If everything is up to snuff you’d be hard pressed to see temps above 195 in the worse of conditions.


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[Kmurt]

I was having an issue where my temp would get up near 200*-210* while idling with the AC on or in stop and go traffic.

Replaced my 22 year old fan clutch with a new AISIN one and it fixed it.

Haven't seen my temp go above 190*.

 

[desertegal7]

if thermostat jiggle at 6°Clock then normal temp should be around 84-86°c, fan clutch kicks in at 87-88, i done it and monitored it in 5VZFEs and 3RZs.

i would suspect your radiator need servicing as some channels infront of the fan might be clogged and not providing enough hot air to the clutch to engage.

we just serviced a boiling radiator and tested afterwards climbing a steep 5km hill with max speed we could and when we reached the top it was 89c and can hear the fan spinning, it went off when reached 84c.

since you replaced the radiator was it dirty? if yes there is U shaped hose of the oil cooler notorious of getting clogged, you might want to check it

also check hoses for deformation, water pump and radiator cap

 

[JoeT4R]

I was having an issue where my temp would get up near 200*-210* while idling with the AC on or in stop and go traffic.

Replaced my 22 year old fan clutch with a new AISIN one and it fixed it.

Haven't seen my temp go above 190*.

This!!! I couldn't agree more with this. I dealt with this for years and once I replaced my fan clutch, the problem went away.

 

[mtbtim]

This video I made covers how to check the fan clutch for proper operation.

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[jross20]

Hey guys, sorry for the long absence. Lot of family issues going on.

Anyway, so I've got an order set up with a bunch of AC parts and also a new fan clutch and fan blade. (Figured I might as well replace the blade while I'm there).

Also, well not related to this thread but related to the topic of temperature and also for those who saw the other thread: I replaced my catalytic converter in the hopes of reducing the temperature. Unfortunately, it did nothing to the temperature, but it actually completely solved my pinging problem!